buku rancangan pengajaran kimia dasar1

Student Guide Book

Subject: Basic Chemistry(ENG100802)

Basic Chemistry Lecturer Team

Faculty of Engineering

University of Indonesia2010

Preface

Chemistry is the study of the composition, properties, and transformations of matter and of chemical laws which are responsible for the changes that take place in nature. During many years, Chemistry have found to be an exciting intellectual challenge and an extraordinary rich and varied part of world heritage. We hope that students will share with the lecturers some of that enthusiasm, excitement, and appreciation.This guidebook is intended to provide guidelines for students taking this subject. By reading this guidebook, it is expected that students understand the learning objectives and should be able to prepare themselves prior to each topic. It is also to guide students in working in group so that they may make the most of the group exercises. Any comments, critics, correction to this guidebook is thankfully accepted.

Depok, January 2011

Lecturer Team

Table of Content

Endorsement Page

Preface

Table of Content

Chapter 1. General Information 1

Chapter 2. Learning Objectives 4

Chapter 3. Outlines of Subject 5

Chapter 4: Teaching Methods and Learning Activities 7

Chapter 5: Exercises and Assignments 9

Chapter 6. Assessment 15

References 18

General Information

1. Subject : Basic Chemistry

2. Subject Code : ENG100802

3. Semester : 1

4. Credit : 2 SKS

5. Year : 2011/2012

6. Type of Subject : Faculty Competence Subject

7. Prerequisite : None

8. Lecturer : Team

9. Description of the subject

As an engineer, you must have understanding on the chemistry that provides not only the basis for much of what goes on in our world but also that it is a vital, continually developing science. In this study the students will learn many subjects such as matter and measurement; atoms, molecules, and ions; stoichiometry; aqueous reactions; thermochemistry; properties of solutions; chemical kinetics; chemical equilibrium; and electrochemistry.

Learning activities will be conducted through various method, which consists of: problem based learning (PBL), interactive lecture, question-based learning, discussion, demonstration and unguided structured assignments. Assessment will be made continuously through a set of exercises, group discussion, mid semester exam and final exam.

This guide book will help students prepare for learning activities throughout the semester for this subject. Preparation may include reading, preparation of worksheet and practice. Achievement of students will entirely be due to their activities and preparation. Construction of knowledge will be made through exercises and questions available in this book. Students are expected to do the exercises, and they may move to further stage as they ready for that. Overall, students are expected to be active learners by acquiring knowledge through thinking and exercising. Students may also use this guidebook to self-assess their achievement.

Student Guide Book 1

Chapter

1

Learning Objectives

2.1. Terminal Learning Objectives

At the completion of this course, the successful student will be able to:

Solve quantitative chemistry problems and demonstrate reasoning clearly and completely. Integrate multiple ideas in the problem solving process.

Describe, explain and model chemical and physical processes at the molecular level in order to explain macroscopic properties.

Classify matter by its state and bonding behavior using the Periodic Table as a reference. Apply important theories such as the Kinetic Molecular or the thermochemistry to the solution of

general chemistry problems.

2.2. Supportive Learning Objectives

1. Students are expected to understand clasification and state of matter, units and uncertainty of measurement, and dimensional analysis from units of measurement.

2. Students are expected to understand the classic and modern theory of atomic structure, and to give the name of inorganic compounds.

3. Students are able to distinguish between molecules and ions and between molecular and ionic compounds.

4. If students are given a chemical reaction, they can analyze the amount of product and yield, and can determine the limiting reactants.

5. If students are given a chemical reaction, they can analyze the types of reactions, concentrations of each components invove in the reactions, and equilibrium constant of the reaction.

6. Students are expected to understand the nature of energy and enthalphy and how to measure the enthalpy formation of pure substance using calorimeter.

7. Students can analyze the entalphy of reaction if they are given a chemical reaction.8. Students can understand periodic table, and can predict properties such as ionization energy and

electron affinities of elements based on their position in the periodic table.9. Students can aunderstand properties of solutions such as pH, acid and based strength and how to

measure or calculated pH of the solutions.


Chapter

2

10. If students are given a galvanic cell they can analyze balance ionic equation, and calculate cell characteristics such as standard cell potential, chemical equilibrium constant and ph of solution, and can predict the spontaneity or nonspontaneity of the reactions in the cell.

11. If the students are given data concentration versus time from the chemical reaction, they can analyze the order of reaction, rate constant and rate of reaction.

12. Students can understand sources of the metallic elements, a brief theory of metallurgy, the making of iron and steel, and properties of semiconductors, ceramics and composites materials.


Outline of Subject

Supportive Learning Objective

Topic Sub-topic Reference

1 1. Matter and Measurement

1.1. The study of chemistry1.2. Classification of matter1.3. Properties of matter1.4. Units of measurement1.5. Uncertainty in measurement1.6. Dimensional Analysis

[1] Chap.1[2] Chap.1

2,3,8 2. Atoms, Molecules, Ions, and Periodic Table

2.1. The atomic theory of matter2.2. The Discovery of atomic structure 2.3. The Modern view of atomic structure 2.4. Molecules and molecular compounds 2.5. Ions and ionic compounds 2.6. Naming inorganic compounds 2.7. Development of the Periodic Table2.8. Electron Shells and Sizes of Atoms2.9. Ionization energy2.10. Electron Affinities2.11. Metals, nonmetals, and metalloids2.12. Group Trends for the Active Metals2.13. Group Trends for Selected Nonmetals

[1] Chap. 2,7,8[2] Chap. 2

4 3. Stoichiometry: Calculations with Chemical Formulas and Equations

3.1. Chemical Equations3.2. Patterns of Chemical Reactivity3.3. Atomic and Molecular Weight3.4. The Mole3.5. Empirical Formula from Analyses3.6. Quantitative Information from

Balance Equations3.7. Limiting Reactants

[1] Chap. 3[2] Chap. 3

5 4. Aqueous Reactions and Solution

4.1. General properties of aqueous solution4.2.Precipitation reaction4.3.Acid-base reaction

[1] Chap. 4,14[2] Chap. 4


Chapter

3

Stoichiometry 4.4.Oxidation-reduction reaction4.5.Concentration of solution4.6.Solution stoichiometry and chemical

analysis 4.7.Equilibrium Constant

6,7 5. Thermochemistry 5.1. The Nature of Energy5.2. The First Law of Themodynamics 5.3. Enthalpy5.4. Entalphies of Reaction5.5. Calorimetry 5.6. Hess’s Law5.7. Entalphies of Formation5.8. Foods and Fuels

[1] Chap. 6[2] Chap.

9 6. Aqueous Equilibria:Acid and Base

6.1. Acid-Base Concepts: Bronsted-Lowry theory

6.2. Acid Strength and Base Strength 6.3. Acid dissociation 6.4. Aqueous Acids and Based6.5. Dissociation of Water6.6. pH6.7. Measuring nad Calculating pH

[1] Chap. 17[2] Chap. 15

10 7. Electrochemistry 7.1. Galvanic Cells7.2. Notation for Galvanic Cells7.3. Cell Potentials and Free Energy

Changes7.4. Standard Reduction Potentials7.5. The Nernst Equation7.6. Electrochemical Determination of pH7.7. Standard Cell Potentials and

Equilibrium Constants7.8. Batteries

[1] Chap. 19[2] Chap. 18

11 8. Chemical Kinetics

8.1. Reaction Rates8.2. Rates Law and Reaction Order8.3. Experimental Determination of a Rate

Law8.4. Integrated Rate Laws for a First-Order

Reaction8.5. Integrated Rate Laws for a Second-

Order Reaction8.6.Half Life of First-Order Reaction8.7. Half Life of Second-Order Reaction8.8. Reaction Mechanism

[1] Chap. 13[2] Chap. 12

12 9. Application of Chemistry

Application of Chemistry- Environmental Chemistry- Introduction to Engineering Material

Provided by Lecturer


Teaching Methods and

Learning Activities

Week/Date Subtopic Supportive Learning Objective

Learning Methods Media/Module Orientation

(O)Exercise

(L)Feedback

(U)1/

General Information SAP Grading Code of Conduct Course Contents

Interactive Lecture

2/

1. The study of chemistry2. Classification of matter3. Properties of matter4. Units of measurement5. Uncertainty in

measurement6. Dimensional Analysis

1 Interactive Lecture

Scele Scele


Chapter

4



(O)Exercise

(L)Feedback

(U)3/

1. The atomic theory of matter

2. The Discovery of atomic structure

3. The Modern view of atomic structure

4. Molecules and molecular compounds

5. Ions and ionic compounds

6. Naming inorganic compounds

7. Development of the Periodic Table

8. Electron Shells and Sizes of Atoms

9. Ionization energy10. Electron Affinities11. Metals, nonmetals, and

metalloids12. Group Trends for the

Active Metals13. Group Trends for

Selected Nonmetals

2, 3, 8 Interactive Lecture

Scele Scele

4/ 1. The atomic theory of matter

2. The Discovery of atomic structure

3. The Modern view of atomic structure

4. Molecules and molecular compounds

5. Ions and ionic compounds

6. Naming inorganic compounds

7. Development of the Periodic Table

8. Electron Shells and Sizes of Atoms

9. Ionization energy10. Electron Affinities11. Metals, nonmetals, and



Selected Nonmetals

2, 3, 8 PBL Pemicu Presentation




(O)Exercise

(L)Feedback

(U)5 1. The atomic theory of

matter2. The Discovery of atomic

structure 3. The Modern view of

atomic structure 4. Molecules and molecular

compounds 5. Ions and ionic

compounds 6. Naming inorganic

compounds7. Development of the

Periodic Table8. Electron Shells and Sizes

of Atoms9. Ionization energy10. Electron Affinities11. Metals, nonmetals, and



Selected Nonmetals

PBL Pemicu Presentasi

6/

1. Chemical Equations2. Patterns of Chemical

Reactivity3. Atomic and Molecular

Weight4. The Mole5. Empirical Formula from

Analyses6. Quantitative Information

from Balance Equations7. Limiting Reactants


Scele Scele

7/

1. General properties of aqueous solution

2. Precipitation reaction3. Acid-base reaction4. Oxidation-reduction

reaction5. Concentration of

solution6. Solution stoichiometry

and chemical analysis 7. Equilibrium Constant


Scele Scele

8 Midsemester Exam




(O)Exercise

(L)Feedback

(U)9/

1. The Nature of Energy2. The First Law of

Themodynamics 3. Enthalpy4. Entalphies of Reaction5. Calorimetry 6. Hess’s Law7. Entalphies of Formation8. Foods and Fuels

6,7 Interactive Lecture

Scele Scele

10/

1. Acid-Base Concepts: Bronsted-Lowry theory

2. Acid Strength and Base Strength

3. Acid dissociation 4. Aqueous Acids and

Based5. Dissociation of Water6. pH7. Measuring nad

Calculating pH


Scele Scele

11/

1. Galvanic Cells2. Notation for Galvanic

Cells3. Cell Potentials and Free

Energy Changes4. Standard Reduction

Potentials5. The Nernst Equation6. Electrochemical

Determination of pH7. Standard Cell Potentials

and Equilibrium Constants

8. Batteries


Scele Scele




(O)Exercise

(L)Feedback

(U)12/

1. Reaction Rates2. Rates Law and Reaction

Order3. Experimental

Determination of a Rate Law

4. Integrated Rate Laws for a First-Order Reaction

5. Integrated Rate Laws for a Second-Order Reaction

6. Half Life of First-Order Reaction

7. Half Life of Second-Order Reaction

8. Reaction Mechanism


Scele Scele

13/

Application of Chemistry- Environmental

Chemistry- Introduction to

Engineering Material


Scele Scele

14/

Review 6,7,9,10,11,12

15/

Final exam period, see the Exam schedule in SIAK NG

16/


Exercises and Assignments

Week SubtopicAssignment

Group Assignment

Individual Assignment

2/ 1. The study of chemistry2. Classification of matter3. Properties of matter4. Units of measurement5. Uncertainty in measurement6. Dimensional Analysis

Assignment 1

3/ 1. The atomic theory of matter2. The Discovery of atomic structure 3. The Modern view of atomic structure 4. Molecules and molecular compounds 5. Ions and ionic compounds 6. Naming inorganic compounds 7. Development of the Periodic Table8. Electron Shells and Sizes of Atoms9. Ionization energy10. Electron Affinities11. Metals, nonmetals, and metalloids12. Group Trends for the Active Metals13. Group Trends for Selected Nonmetals

Group report and discussion/ Presentation

Individual report

4/ 1. The atomic theory of matter2. The Discovery of atomic structure 3. The Modern view of atomic structure 4. Molecules and molecular compounds 5. Ions and ionic compounds 6. Naming inorganic compounds 7. Development of the Periodic Table8. Electron Shells and Sizes of Atoms9. Ionization energy10. Electron Affinities11. Metals, nonmetals, and metalloids12. Group Trends for the Active Metals13. Group Trends for Selected Nonmetals


Individual report

5/ 1. The atomic theory of matter2. The Discovery of atomic structure 3. The Modern view of atomic structure 4. Molecules and molecular compounds 5. Ions and ionic compounds 6. Naming inorganic compounds 7. Development of the Periodic Table


Individual report


Chapter

5


Group Assignment


8. Electron Shells and Sizes of Atoms9. Ionization energy10. Electron Affinities11. Metals, nonmetals, and metalloids12. Group Trends for the Active Metals13. Group Trends for Selected Nonmetals

6/ 1. Chemical Equations2. Patterns of Chemical Reactivity3. Atomic and Molecular Weight4. The Mole5. Empirical Formula from Analyses6. Quantitative Information from Balance

Equations7. Limiting Reactants

Assignment 2

7/ 1. General properties of aqueous solution2. Precipitation reaction3. Acid-base reaction4. Oxidation-reduction reaction5. Concentration of solution6. Solution stoichiometry and chemical

analysis 7. Equilibrium Constant

Assignment 3

8/ 1. The Nature of Energy2. The First Law of Themodynamics 3. Enthalpy4. Entalphies of Reaction5. Calorimetry 6. Hess’s Law7. Entalphies of Formation8. Foods and Fuels

Assignment 4

9/ 1. Acid-Base Concepts: Bronsted-Lowry theory

2. Acid Strength and Base Strength 3. Acid dissociation 4. Aqueous Acids and Based5. Dissociation of Water6. pH7. Measuring nad Calculating pH

Assignment 5

10/ 1. Galvanic Cells2. Notation for Galvanic Cells3. Cell Potentials and Free Energy Changes4. Standard Reduction Potentials

Assignment 6



Group Assignment


5. The Nernst Equation6. Electrochemical Determination of pH7. Standard Cell Potentials and Equilibrium

Constants8. Batteries

11/ 1. Reaction Rates2. Rates Law and Reaction Order3. Experimental Determination of a Rate

Law4. Integrated Rate Laws for a First-Order

Reaction5. Integrated Rate Laws for a Second-Order

Reaction6. Half Life of First-Order Reaction7. Half Life of Second-Order Reaction8. Reaction Mechanism

Assignment 7

13/ Application of Chemistry- Environmental Chemistry- Introduction to Engineering Material

Paper

14/ Review

15/ Final exam period, see the Exam schedule in SIAK NG

16/

17/


Assignment I

1. Each of the following can be classified as a heterogeneous mixture, pure substance, compound, or element. How would you classify each?

Iced tea

heterogeneous mixture

homogeneous mixture

pure substance

compound

element

Isopropyl alcohol


homogeneous mixture

pure substance

compound

pure substance and compound

Helium

pure substance and element

homogeneous mixture

pure substance

compound

element

Sugar


homogeneous mixture

compound

pure substance

pure substance and compound A freshly cut surface of sodium quickly becomes dull with a film of white sodium oxide when it is exposed to air. Is this a


5

physical change or a chemical change?

Physical

Chemical

Another property of sodium is that it conducts electricity, as do all metals. Is electrical conductivity an intensive or extensive property of sodium metal?

Intensive

Extensive How many significant figures are there in the number 1020.5?

2

3

4

5

6

How many significant figures are there in the number 0.0012?

1

2

3

4

5

How many significant figures should there be in the answer to the following problem?

2

3

4

5

6


6

7

8

9

What is the answer to the following problem, reported to the correct number of significant figures?

0.11807

0.1181

0.118

0.12

0.1


10

KIMIA DASAR PEMICU 1: TEMBAGA DALAM KEHIDUPAN KITATopik I Tembaga atau copper adalah senyawa yang banyak ditemukan secara alamiah di lingkungan dan disebarkan melalui fenomena alam. Manusia pun banyak menggunakan senyawa ini, misalnya dalam industri atau pertanian. Produksi tembaga meningkat pada dekade terakhir ini sehingga jumlah tembaga di lingkungan meningkat.Hampir semua bentuk senyawa tembaga akan mengendap atau terikat pada sedimen air atau partikel tanah. Tembaga tidak terurai di lingkungan dan karenanya dapat terakumulasi pada tanaman dan hewan bila tembaga tersebut terdapat di tanah. Akan tetapi senyawa tembaga yang larut dalam air menjadi ancaman terbesar pada kesehatan manusia.Walaupun kekhawatiran akan bahaya ancaman kesehatan pada manusia, penyerapan tembaga oleh tubuh diperlukan karena tembaga, dalam jumlah kecil, termasuk dalam unsur logam yang penting untuk kesehatan manusia. Tubuh manusia dapat mengatasi tembaga dalam jumlah relatif besar. Namun tembaga dalam jumlah yang terlalu banyak dapat menyebabkan masalah kesehatan yang penting.Tubuh manusia dewasa mengandung tembaga sebanyak 1,4 sampai 2,1 mg/kg berat tubuh. Dengan demikian untuk manusia sehat dengan berat sekitar 60 kg kira-kira akan mengandung 0,1 gram tembaga. Tembaga dan beberapa unsur logam bersama dengan asam amino, asam lemak, serta vitamin diperlukan untuk proses metabolisme normal.Selain kelebihan jumlah tembaga, masalah yang juga serius adalah defisiensi tembaga karena kurangnya jumlah konsumsi tembaga melalui air minum atau makanan. Defisiensi tembaga juga bisa mengantar pada penyakit yang parah dan kematian.

Tugas :1. Dapatkah anda menjelaskan apakah tembaga dari aspek-aspek kimianya? 2. Bagaimana senyawa tersebut dapat berada di lingkungan maupun dalam tubuh manusi. 3.Bagaimana pengaruhnya pada kehidupan manusia, hewan maupun tumbuhan bila berlebihan adanya?Pendapat negatif (kontra) tentang pengaruh tembaga pada manusia, hewan, maupun tumbuhan didasarkan pada informasi2 berikut:Meskipun Cu merupakan komponen penting yang diperlukan untuk metabolisme manusia , namun keberadaannya dalam jumlah yang besar dapat menyebabkan keracunan. Jumlah Cu yang akut dalam tubuh (lebih besar dari 30 mg/liter Cu) dapat menyebabkan beberapa gejala peradangan pada usus, dan juga mual-mual, kejang dan muntah-muntah.

4. Jelaskan satuan2 lain (3buah) yang bisa digunakan untuk menyatakan kandungan suatu zat dalam larutan?

Pendapat tentang logam Cu yang bersifat karsinogenik masih belum dapat dipastikan kebenarannya.

5. Apakah yang dimaksud sifat karsinogenik dan apa pula yang dimaksud dengan “free radicals”?


Cu dibutuhkan tanaman untuk pertumbuhannya dalam jumlah kecil (micronutrient). Tanah-tanah yang kaya akan kandungan logam Cu cenderung menyebabkan jumlah tanaman yang dapat tumbuh di tanah tersebut menjadi terbatas.

6.” Chemicals nutrients” apa saja yang dibutuhkan oleh tanaman untuk dapat tumbuh dengan subur? 7. Chemical nutrients mana sajakah yang biasanya masih perlu ditambahkan melalui pemberian pupuk buatan?8. Tahukah Sdr. bahwa pupuk2 buatan (fertilizer) itu juga bisa merusak lingkungan, beri contoh 3 pencemaran akibat pemupukan yang berlebihan.

PEMICU 2: Waspada, Klorin Bisa Timbulkan Kanker

Selasa, 14 September 2010 | 11:20 WIB

Kompas.com - Kolam renang dalam ruangan tertutup (indoor) menjadi pilihan banyak orang karena terhindar dari sinar matahari. Namun ada baiknya Anda waspada karena menurut sebuah penelitian, berenang di dalam kolam renang indoor yang diberi klorin bisa menyebabkan kanker.

Klorin memang sering digunakan sebagai zat pembasmi kuman di kolam renang. Dalam penelitian yang dilakukan oleh ilmuwan dari Centre of Research in Environmental Epidemiology and Research Institute Hospital del Mar, Spanyol, diketahui bahwa kolam renang indoor yang diberi klorin bisa menyebabkan mutasi DNA secara permanen (mutagenicity).

Penelitian tersebut dilakukan terhadap 49 orang perenang. "Bukti terjadinya efek genotoxic (mutasi menjadi karsinogen) terlihat pada para perenang setelah mereka berenang selama 40 menit di kolam renang indoor dan mengandung klorin," kata para ilmuwan dalam pernyataannya.

Para ilmuwan mengaitkan risiko kanker ini dengan efek klorin terhadap sistem pernapasan para perenang. Beberapa waktu lalu juga dipublikasikan penelitian mengenai efek klorin terhadap penyakit asma pada anak.

Menurut para ahli, kalau klorin bersenyawa dengan zat organik, seperti air seni atau keringat,m maka akan menghasilkan senyawa sejenis nitrogen triklorin yang dapat mengakibatkan iritasi hebat. Senyawa organik tersebut, lanjutnya, dapat bereaksi menjadi gas di kolam tertutup dan membawa dampak terhadap sel-sel tubuh yang melindungi paru-paru.

Meski efek samping klorin ini cukup berbahaya, namun Anda tidak perlu menghindari olahraga berenang mengingat cukup banyak manfaat kesehatan dari kegiatan berenang.

"Kami tidak menyarankan orang untuk berhenti berenang namun kami menghimbau pengelola kolam renang untuk mengurangi penggunaan klorin," kata Manolis Kogevinas, peneliti.


Tugas :1. Dapatkah anda menjelaskan apakah klorin dari aspek2 kimianya? 2. Bagaimana unsur tersebut dapat berada di lingkungan maupun dalam tubuh manusia. 3.Bagaimana pengaruhnya pada kehidupan manusia, hewan maupun tumbuhan bila berlebihan adanya?4. Jelaskan satuan2 yang bisa digunakan untuk menyatakan kandungan suatu zat dalam larutan?Penelitian tersebut dilakukan terhadap 49 orang perenang. "Bukti terjadinya efek genotoxic (mutasi menjadi karsinogen) terlihat pada para perenang setelah mereka berenang selama 40 menit di kolam renang indoor dan mengandung klorin," kata para ilmuwan dalam pernyataannya.5. Apa yang dimaksud dengan genotoxic, mutasi dan karsinogen ?Menurut para ahli, kalau klorin bersenyawa dengan zat organik, seperti air seni atau keringat, maka akan menghasilkan senyawa sejenis nitrogen triklorin yang dapat mengakibatkan iritasi hebat. Senyawa organik tersebut, lanjutnya, dapat bereaksi menjadi gas di kolam tertutup dan membawa dampak terhadap sel-sel tubuh yang melindungi paru-paru.6. gambarkan senyawa-senyawa nitrogen triklorin, sebutkan juga senyawa-senyawa organik lainnya yang mungkin terbentuk dengan adanya klorin ?

Meski efek samping klorin ini cukup berbahaya, namun Anda tidak perlu menghindari olahraga berenang mengingat cukup banyak manfaat kesehatan dari kegiatan berenang.

"Kami tidak menyarankan orang untuk berhenti berenang namun kami menghimbau pengelola kolam renang untuk mengurangi penggunaan klorin," kata Manolis Kogevinas, peneliti.

7. Apakah sudah ada pengganti klorin ? kalau ada sebutkan apa saja ?8. Kira-kira gas apa saja yang berada di didalam kolam renang indoor dan apa bedanya dengan yang berada di kolam renang outdoor ?

Keterangan

Pembuatan Makalah kelompok:

1. Jumlah halaman 10 - 16 hlm2. Kertas A4, huruf size 12, spasi 1.5

3. Pakai lembar cover yang berisi: judul, nomor Pemicu, informasi kelompok.

4. Buat daftar isi bila lebih dari 10 halaman, dan daftar pustaka.

5. lampiran bisa ditambahkan bila perlu.


6. Bagian pendahuluan: Latar belakang, problem statement, informasi yang diperlukan.

7. Bagian isi: pembahasan isu-isu pembelajaran.

8. Penutup: kesimpulan.

Pembuatan Slide untuk Presentasi:

1. Jumlah halaman 8 - 14 slide ppt.2. Page set up: landscape, huruf size 20, background terang.

3. Pakai lembar cover yang berisi: judul, nomor Pemicu, informasi kelompok.

4. Bagian pendahuluan: Latar belakang, problem statement dalam 1 slide.

5. Bagian isi: pembahasan isu-isu pembelajaran.

6. Penutup: kesimpulan.

Ketentuan untuk mahasiswa yang tidak presentasi:

1. Bagi kelompok yang akan presentasi, harus mengisi borang yang telah disediakan.2. Bagi kelompok bernomer gasal mengerjakan Tugas Pemicu 1 dan bagi kelompok

bernomer genap mengerjakan Tugas Pemicu 2 pada kertas yang sudah disediakan.

Semua pekerjaan dikelas dikumpulkan pada waktu selesai kuliah.


Pemicu PBL 1: MSG, Amankah dikonsumsi?

Beberapa kali muncul kekhawatiran di media, terutama diwakili oleh Lembaga Konsumen, soal di pasaran ada berbagai produk makanan ringan dalam kemasan yang biasa dikonsumsi anak-anak, tidak mencantumkan kandungan MSG (vetsin). Kritik tersebut menyatakan, konsumsi MSG dalam jumlah tertentu mengancam kesehatan anak-anak. Menteri Kesehatan pun sudah memberi pernyataan yang meminta BPOM menarik produk makanan kemasan yang tidak mencantumkan kandungan MSG/ Seberapa jauhkah sebenarnya MSG membahayakan kesehatan manusia ?

MSG memberikan rasa gurih dan nikmat pada berbagai macam masakan, walaupun masakan itu sebenarnya tidak memberikan rasa gurih yang berarti. Penambahan MSG ini membuat masakan seperti daging, sayur, sup berasa lebih nikmat dan gurih. MSG dijual dalam berbagai bentuk produk dan kemasan, produk penyedap rasa seperti Ajinomoto atau Royco mengandung MSG sebagai salah satu bahan penyedap rasa. Produk makanan siap saji, makanan beku maupun makanan kaleng juga mengandung MSG dalam jumlah yang cukup besar. Selain lada dan garam, botol berlabel penyedap rasa yang mengandung MSG juga dapat dengan mudah ditemukan di rak bumbu dapur maupun di atas meja restoran. Umumnya, Restoran Cina banyak menggunakan MSG untuk menyedapkan masakan-masakannya.

Sejauh ini, belum banyak penelitian tentang konsumsi MSG ini dilakukan langsung terhadap manusia. Hasil dari penelitian dari hewan, memang diupayakan untuk dicoba pada manusia. Tetapi hasil-hasilnya masih bervariasi. Sebagian menunjukkan efek negatif MSG seperti pada hewan, tetapi sebagian juga tidak berhasil membuktikan.

TUGAS I:

1. Anda sebagai seorang ahli kimia, diminta oleh pihak BPOM untuk memberikan penjelasan mengenai MSG sebagai penyedap makanan dari sisi bidang keahlian/ilmu anda. Setelah mendengar penjelasan ini, pihak BPOM berharap dapat mengetahui seberapa besar tingkat kebutuhan manusia akan MSG, seberapa jauh MSG dapat


membahayakan kesehatan manusia dan menentukan sanksi yang diberikan pada produsen makanan yang menyalahgunakan penggunaan MSG tsb. Sewaktu mempersiapkan presentasi anda membuat ringkasan mengenai beberapa hal penting yang menyangkut penggunaan MSG dalam bahan makanan, Apa yang akan anda tulis?

MSG basic:- What is MSG?- How long has MSG been used?- How is MSG made?

Using MSG in Food:- How does MSG enhance food flavor?- How is MSG used in cooking- How much does an average person consume?- How does MSG affect metabolism?

MSG benefit:- Improving taste- Reducing sodium intake.

MSG disadvantage

2. Menurut anda apa yang sesungguhnya menjadi kontroversi yang menyangkut penggunaan MSG ini dalam makanan? Bagaimana tanggapan saudara?

- Hasil penelitian mengenai efek MSG terhadap kesehatan manusia.

3. Jika anda menjadi salah seorang wakil yang duduk di lembaga konsumen, apa yang bisa anda sarankan pada para produsen makanan di Indonesia, terutama yang menyangkut penggunaan MSG pada makanan?

- Aturan mengenai kualifikasi makanan dari BPOM

TUGAS II:

Anda ingin sekali bisa lebih memahami bagaimana MSG sebagai salah satu senyawa kimia memiliki pengaruh yang besar terhadap cita rasa masakan dan juga kesehatan. Sebagai seorang yang berkecimpung dalam bidang ilmu kimia, tentunya anda harus dapat mendalami terlebih dahulu tentang komponen kimia pembentuk senyawa MSG dan sifat-sifatnya, dengan menjawab beberapa pertanyaan di bawah ini.

4. Dari literatur diperoleh informasi bahwa Natrium merupakan komponen utama yang terdapat dalam MSG dan unsur tersebut tercantum dalam tabel sistem periodik. Mengapa dalam tabel tersebut unsur Na memiliki no atom 11? Bagaimana sesungguhnya unsur-unsur dalam tabel tersebut di susun? Mengapa unsur-unsur tersebut perlu disusun sedemikian rupa?

- Definisi Sistem periodik- Dasar-dasar penyusunan unsur dalam sistem periodik- Manfaat penyusunan unsur-unsur dalam suatu sistem periodik.


5. Informasi apa saja yang dapat anda peroleh mengenai unsur-unsur dari tabel sistem peridik tersebut? Adakah kemiripan sifat dari unsur Na dengan beberapa unsur lain yang ada dalam tabel tersebut dan bagaimana hal demikian terjadi? Bagaimana kecenderungan sifat unsur Na dibandingkan dengan unsur lain dalam sistem periodik tersebut?

- Komponen-komponen dalam sistem peridiodik unsur- Faktor penting yang menentukan kemiripan sifat unsur- Sifat-sifat unsur dan kecenderungannya dalam sistem periodik.

6. Apakah manfaat yang anda peroleh dengan mengetahui sifat-sifat unsur yang terdapat dalam sistem periodik?

7. Berdasarkan teori yang telah dibaca dari berbagai literatur/pustaka mengenai senyawa kimia didapat informasi bahwa atom-atom pada umumnya tidak ditemukan dalam keadaan bebas (kecuali pada temperatur tinggi), melainkan sebagai suatu molekul. Dengan demikian unsur Na di alam juga diperoleh dalam bentuk suatu unsur yang berikatan dengan unsur lainnya membentuk suatu senyawa kimia. Bagaimana anda bisa meramalkan bentuk geometri dari suatu senyawa kimia?

- Jenis-jenis bentuk geometri senyawa kimia- Langkah-langkah dalam meramalkan bentuk geometri molekul/senyawa

kimia

TUGAS III:

8. Garam beryodium merupakan garam NaCl yang difortifikasi dengan kalium iodida. Bagaimana anda menentukan bilangan kuantum dari unsur-unsur pembentuk kalium iodida tersebut?. Apakah susunan bilangan kuantum tersebut mengikuti prinsip Larangan Pauli ? Orbital-orbital apa sajakah yang ditempati oleh elektron dari atom-atom tersebut ? Dimanakah letak unsur-unsur tersebut dalam sistem periodik ? Untuk dapat membentuk senyawa kalium iodida, ion-ion apakah yang terbentuk dari unsur-unsur tersebut ?

Keterangan Makalah:

9. minimum 8 halaman maksimum 16 halaman10.kertas A4, size 12, spasi 1.5

11.ada lembar cover yang berisi: judul, nomor PBL, informasi kelompok.

12.ada daftar isi bila lebih dari 10 halaman, dan daftar pustaka.

13. lampiran bisa ditambahkan bila perlu.

14.Bagian pendahuluan: Latar belakang, problem statement, informasi yang diperlukan (melampirkan peta konsep).

15.Bagian isi: pembahasan isu-isu pembelajaran.


16.Penutup: kesimpulan.


GARAM DAPUR, BAHAN KIMIA MULTI-MANFAAT

Garam, natrium klorida, atau garam dapur, merupakan bahan kimia yang sangat bermanfaat dalam kehidupan kita. Diketahui ada lebih dari 14.000 kegunaan bahan ini. Makanan kita akan hambar jika kurang garam. Semua binatang, juga manusia, membutuhkan baik natrium maupun klorida untuk kehidupan dan kesehatan. Karena tubuh tidak dapat memproduksi natrium maupun klorida, maka keduanya merupakan nutrisi yang ‘esensial’.

Setiap orang menggunakan garam, langsung maupun tidak langsung. Setiap orang Amerika mengkonsumsi 16 ton garam selama hidupnya, 402 pon setahun untuk setiap orang. Hanya sedikit saja dari jumlah yang besar tesebut dikonsumsi sebagai makanan. Berikut ini pembagian dari penggunaan utama garam di Amerika (www.saltinstitute.org/)

Gambar 1. Penggunaan utama garam di Amerika

Secara fisik, garam tidak jauh berbeda dengan gula. Tetapi, jika kita melarutkan gula atau garam ke dalam air, akan terjadi fenomena yang berbeda: larutan garam dapat menyalakan bohlam lampu sedangkan larutan gula tidak.

Mengapa terjadi perbedaan tersebut? Pertanyaan tentang pengertian larutan dll.

Salah satu penggunaan terbesar dari garam di Amerika Serikat adalah sebagai “highway salt”. Di negara-negara 4 musim, garam digunakan untuk mencairkan es atau salju di jalan raya ataupun jalan umum lainnya. Saat ini, garam merupakan pencair es jalan raya yang paling efektif, mudah diperoleh, dan ekonomis. Lebih dari 40% garam kering yang dihasilkan di Amerika Serikat digunakan sebagai pencair es.

a. Secara kimia, apa yang terjadi jika garam ditebarkan di atas es atau salju? Mengapa es maencair setelah berkontak dengan garam?

b. Jika kita gunakan garam lain selain garam dapur untuk mencairkan sejumlah tertentu es, bagaimana kuantitas (jumlah) dari garam tersebut dibandingkan dengan garam dapur? Samakah? Jelaskan!

c. Jika kita menjerang sejumlah air pada 2 panci yang berbeda, dimana satu panci ditambahkan 100 gram garam dan panci yang lainnya tidak,


http://www.saltinstitute.org/

bagaimana dengan temperatur air pada kedua panci tersebut saat air di panci telah mendidih? Apakah sama atau berbeda? Mengapa?

Penggunaan garam terbesar adalah sebagai bahan baku dalam pembuatan bahan-bahan kimia. Salah satu industri yang menggunakan garam sebagai bahan baku adalah industri pulp dan kertas untuk menghasilkan klorin dan soda kaustik. Klorin dihasilkan melalui elektrolisis. Arus listrik dialirkan melalui garam NaCl cair menghasilkan klorin dan sebuah ion sodium (Na+) yang dapat bereaksi dengan air di dalam sel elektrolisis menjadi soda kaustik dan gas hidrogen sebagai produk samping.

a. Tuliskan persamaan reaksi yang terjadi pada pembuatan klorinb. Jika satu ton garam diproses untuk menghasilkan klorin dan soda

kaustik, (i) berapa tekanan gas pada sel elektrolisis setelah reaksi

berlangsung sempurna? Asumsikan bahwa temperatur di dalam sel adalah 25OC.

(ii) Berapa tekanan parsial dari hydrogen?(iii) Berapa jumlah kostik soda yang dihasilkan dan berapa air

yang dibutuhkan dalam proses ini?d. Jika dua atau lebih gas dicampur, masing-masing gas akan mempunyai

tekanan sendiri yang disebut tekanan parsial. Jelaskan mengenai tekanan parsial!

e. Bisakah gas membentuk larutan? Apakah yang dimaksud dengan larutan?f. Jika kita mencampur minyak dan air, mereka akan membentuk campuran

yang immiscible. Apakah yang dimaksud dengan immiscible? Apakah ada campuran gas yang immiscible? Mengapa?


Assignment 2P R A C T I C E T E S T

1. Balance the following equation:___NH3 + ___O2 ___NO2 + ___H2O

The balanced equation shows that 1.00 mole of NH3 requires ___ mole(s) of O2.

a) 0.57 c) 1.33b) 1.25 d) 1.75

2. Write a balanced equation for the combustion of acetaldehyde, CH3CHO.

When properly balanced, the equation indicates that ___ mole(s) of O2 are required for

each mole of CH3CHO.

a) 1 c) 2.5b) 2 d) 3

3. Balance the following equation with the SMALLEST WHOLE NUMBER COEFFICIENTS possible. Select the number that is the sum of the coefficients in the balanced equation:

___KClO3 ___KCl + ___O2a) 5 b) 6 c) 7 d) 8

4. Write a balanced equation for the combustion of propane, C3H8.

When properly balanced, the equation indicates that ___ moles of O2 are required for each

mole of C3H8.

a) 3 b) 3.5 c) 5 d) 8

5. What is the total mass of products formed when 16 grams of CH4 is burned with excess oxygen?a) 80 g c) 36 gb) 44 g d) 32 g

6. Calculate the mass of hydrogen formed when 25 g of aluminum reacts with excess hydrochloric acid.

2Al + 6HCl 2 AlCl3 + 3 H2


a) 0.41 g c) 1.2 gb) 0.92 g d) 2.8 g

7. How many grams of the mixed oxide, Fe3O4, are formed when 6.00 g of O2 react with Fe

according to3Fe + 2O2 Fe3O4

a) 43.4 c) 174b) 86.8 d) 21.7

8. For the reaction:2MnO2 + 4KOH + O2 + Cl2

2KMnO4 + 2KCl + 2H2O

there is 100. g of each reactant available. Which reagent is the limiting reagent?[Molar Masses: MnO2=86.9; KOH=56.1; O2=32.0; Cl2=70.9]

a) MnO2 c) O2b) KOH d) Cl2

9. How many grams of nitric acid, HNO3, can be prepared from the reaction of 92.0 g of NO2 with 36.0 g H2O?

3NO2 + H2O 2HNO3 + NO

a) 64 c) 84b) 76 d) 116


10. The reaction of 25.0 g benzene, C6H6, with excess HNO3 resulted in 21.4 g C6H5NO2.

What is the percentage yield?C6H6 + HNO3 C6H5NO2 + H2O

a) 100% c) 54.3%b) 27.4% d) 85.6%

11. How many grams of H2O will be formed when 16.0 g H2 is allowed to react with 16.0 g

O2 according to

2H2 + O2 2H2O?

a) 18.0 g c) 9.00 gb) 144 g d) 32.0 g

12. When 8.00 g of H2 reacts with 32.0 g of O2 in an explosion, 2H2 + O2 2H2O, the final

gas mixture will contain:a) H2, H2O, and O2 c) O2 and H2O only

b) H2 and H2O only d) H2 and O2 only

13. 1.056 g of metal carbonate, containing an unknown metal, M, were heated to give the metal oxide and 0.376 g CO2.

MCO3(s) + heat MO(s) + CO2(g)

What is the identity of the metal M?a) Mg c) Znb) Cu d) Ba


14. Styrene, the building block of polystyrene, is a hydrocarbon, a compound containing only C and H. A given sample is burned completely and it produces 1.481 g of CO2 and 0.303

g of H2O. Determine the empirical formula of the compound.

a) CH c) C2H3b) CH2 d) C2H5



1. Balance the following equation:___NH3 + ___O2 ___NO2 + ___H2O

The balanced equation shows that 1.00 mole of NH3 requires ___ mole(s) of O2.

a) 0.57 c) 1.33b) 1.25 d) 1.75

2. Write a balanced equation for the combustion of acetaldehyde, CH3CHO.

When properly balanced, the equation indicates that ___ mole(s) of O2 are required for

each mole of CH3CHO.

a) 1 c) 2.5b) 2 d) 3

3. Balance the following equation with the SMALLEST WHOLE NUMBER COEFFICIENTS possible. Select the number that is the sum of the coefficients in the balanced equation:

___KClO3 ___KCl + ___O2a) 5 b) 6 c) 7 d) 8

4. Write a balanced equation for the combustion of propane, C3H8.

When properly balanced, the equation indicates that ___ moles of O2 are required for each

mole of C3H8.

a) 3 b) 3.5 c) 5 d) 8

5. What is the total mass of products formed when 16 grams of CH4 is burned with excess oxygen?a) 80 g c) 36 gb) 44 g d) 32 g

6. Calculate the mass of hydrogen formed when 25 g of aluminum reacts with excess hydrochloric acid.

2Al + 6HCl 2 AlCl3 + 3 H2a) 0.41 g c) 1.2 g


b) 0.92 g d) 2.8 g

7. How many grams of the mixed oxide, Fe3O4, are formed when 6.00 g of O2 react with Fe

according to3Fe + 2O2 Fe3O4

a) 43.4 c) 174b) 86.8 d) 21.7

8. For the reaction:2MnO2 + 4KOH + O2 + Cl2

2KMnO4 + 2KCl + 2H2O

there is 100. g of each reactant available. Which reagent is the limiting reagent?[Molar Masses: MnO2=86.9; KOH=56.1; O2=32.0; Cl2=70.9]

a) MnO2 c) O2b) KOH d) Cl2

9. How many grams of nitric acid, HNO3, can be prepared from the reaction of 92.0 g of NO2 with 36.0 g H2O?

3NO2 + H2O 2HNO3 + NO

a) 64 c) 84b) 76 d) 116


10. The reaction of 25.0 g benzene, C6H6, with excess HNO3 resulted in 21.4 g C6H5NO2.

What is the percentage yield?C6H6 + HNO3 C6H5NO2 + H2O

a) 100% c) 54.3%b) 27.4% d) 85.6%

11. How many grams of H2O will be formed when 16.0 g H2 is allowed to react with 16.0 g

O2 according to

2H2 + O2 2H2O?

a) 18.0 g c) 9.00 gb) 144 g d) 32.0 g

12. When 8.00 g of H2 reacts with 32.0 g of O2 in an explosion, 2H2 + O2 2H2O, the final

gas mixture will contain:a) H2, H2O, and O2 c) O2 and H2O only

b) H2 and H2O only d) H2 and O2 only

13. 1.056 g of metal carbonate, containing an unknown metal, M, were heated to give the metal oxide and 0.376 g CO2.

MCO3(s) + heat MO(s) + CO2(g)

What is the identity of the metal M?a) Mg c) Znb) Cu d) Ba


14. Styrene, the building block of polystyrene, is a hydrocarbon, a compound containing only C and H. A given sample is burned completely and it produces 1.481 g of CO2 and 0.303

g of H2O. Determine the empirical formula of the compound.

a) CH c) C2H3b) CH2 d) C2H5


Assignment 4

reaksi H

Mg(s) + 2 HCl(aq) MgCl2(aq) + H2(g) -467 kJ/mol

MgO(s) + 2 HCl(aq) MgCl2(aq) + H2O(l) -151 kJ/mol

27. berdasarkan informasi diatas, dan diberikan data untuk air, Hf = -286 kJ/mol, berapa Hf

MgO(s) ?

(A) -904 kJ/mol (C) -334 kJ/mol

(B) -602 kJ/mol (D) -30 kJ/mol

22. Karbon bereaksi dengan oksigen berdasarkan reaksi berikut 2C(s) + O2(g) 2CO(g)

H = -220 kJPernyataan mana yang benar ?

1. reaksi adalah eksotermik.

2. pembakaran 0.50 mol karbon menghasilkan 55 kJ energy panas

(A) hanya 1 (C) 1 dan 2

(B) hanya 2 (D) bukan 1 atau 2

24. Gunakan data, H° untuk reaksi ini

NO(g) + ½ O2(g) NO2(g)

Reaksi H°, kJ/mol

½ N2(g) + ½ O2(g) NO(g) 90.2 kJ/mol

½ N2(g) + O2(g) NO2(g) 33.2 kJ/mol

(A) -57.0 (C) +28.5

(B) -28.5 (D) +57.0

25. 1.0 g sample A pada 100 °C ditambahkan kedalam 100 ml H2O pada 25 °C. Menggunakan

100 mL H2O terpisah lainnya, prosedur diulang dengan sampel B dengan sampel C.

Bagaimana temperatur akhir dari air ?

Sampel Panas spesifik

A 0.60 J g-1 C-1

B 0.40 J g-1 C-1

C 0.20 J g-1 C-1

(A) Tc > Tb > Ta (C) Ta > Tb > Tc

(B) Tb > Ta > Tc (D) Ta = Tb = Tc


26. Seberapa besar benzene, C6H6(l), harus dibakar didalam sebuah bomb calorimeter untuk

mencapai temperaturnya 1.5 °C ? Diberikan: Konstanta calorimeter 12.59 kJ/C dan

H°:pembakaran for C6H6 = -41.9 kJ g¯1

(A) 0.45 g (C) 3.3 g

(B) 2.8 g (D) 8.4 g

19. 30.0 mL air pada 10 °C dicampur dengan 50.0 mL air pada 60 °C. Berapa temperature akhir

dari campuran ?

(A) 31 °C (C) 41 °C

(B) 35 °C (D) 46 °C

24. Berapa nilai H° untuk reaksi

Fe2O3(s) + 3H2O(l) 2Fe(OH)3(s)

Senyawa H°f (kJ/mol)

Fe2O3(s) -824.2

Fe(OH)3(s) -823.0

H2O(l) -285.8

(A) 35.6 kJ (C) 858.6 kJ

(B) 286 kJ (D) -536 kJ

25. Ketika Na2S2O3 . 3H2O dilarutkan dalam air, larutan menjadi dingin. Diagram mana yang

merepresentasikan kejadian dalam larutan tersebut ?


NChO 1996

22. The standard enthalpy of formation (H°f) for sodium bromide is the enthalpy change for

the reaction

(A) Na+(g) + Br¯(g) NaBr(g)

(B) Na+(g) + Br¯(g) NaBr(s)

(C) 2 Na(s) + Br2(g) 2 NaBr(s)

(D) Na(s) + ½ Br2(l) NaBr(s)

23. Use the standard enthalpies of formation in the table to calculate H° for this reaction:

2 CrO42¯(aq) + 2 H+(aq) Cr2O7

2¯(aq) + H2O(l)

Substance H°f, kJ mol¯1

CrO42¯(aq) - 881.2

Cr2O72¯(aq) - 1490.3

H+(aq) 0

H2O(l) - 285.8

(A) 272.1 kJ (C) -13.7 kJ

(B) 13.7 kJ (D) -272.1 kJ

NChO 1995

21. For which of these processes is the sign of the enthalpy change different from the others?

(A) Al2O3(s) 2 Al(s) + 3/2 O2(g)

(B) H2O(s) H2O(l)

(C) Cl2(g) 2Cl(g)

(D) Cl(g) + e¯ Cl¯(g)

22. The standard enthalpy of formation (H°) for nitrogen(IV) oxide is the enthalpy change for

the reaction

(A) N(g) + 2O(g) NO2(g)

(B) ½ N2(g) + O2(g) NO2(g)

(C) ½ N2O4(g) NO2(g)

(D) NO(g) + ½ O2 NO2(g)

23. In a bomb calorimeter, reactions are carried out at

(A) constant volume.

(B) constant pressure.


(C) 1 atm pressure and 25 °C.

(D) 1 atm pressure and 0 °C.


26. Consider the reaction

Hg(l) + 2 Ag+(aq) Hg2+(aq) + 2 Ag(s)

What is the enthalpy change for this reaction if H°f for Ag+ (aq) is +105.6 kJ mol¯1 and for

Hg2+ (aq) is +171.1 kJ mol¯1?

(A) 65.5 kJ are evolved per mole of Hg.

(B) 65.5 lK are absorbed per mole of Hg.

(C) 40.1 kJ are evolved per mole of Hg.

(D) 40.1 kJ are absorbed per mole of Hg.

NChO 1994

24. A student mixes 100 mL of 0.50 M NaOH with 100 mL of 0.50 M HCl in a styrofoam cup

and observes a temperature increase of T1. When she repeats this experiment using 200mL

of each solution, she observes a temperature change of T2. If no heat is lost to the

surroundings or absorbed by the styrofoam cup, what is true about T1 and T2?

(A) T2 = T1 (C) T2 = 2 T1

(B) T2 = 0.5 T1 (D) T2 = 4 T1

27) Given these values of H°: H°

CS2(l) + 3O2(g) CO2(g) + 2SO2(g) - 1077 kJ

H2(g) + O2(g) H2O2(l) - 188 kJ

H2(g) + (1/2) O2(g) H2O(l) - 286 kJ

What is the value of H° for this reaction?

CS2(l) + 6 H2O2(l) CO2(g) + 6 H2O(l) + 2 SO2(g)

(A) -1175 kJ (C) -1665 kJ

(B) -1551 kJ (D) -3921 kJ

NChO 1993

13. Which process or reaction has a positive H?

(A) H2O(l) H2O(s)

(B) 2CH3OH(l) + 3O2(g) 2CO2(g) + 4H2O(l)

(C) CO2(s) CO2(g)

(D) 2 Na(s) + Cl2(g) 2 NaCl (s)

15. For the reaction

H2(g) + I2(s) 2 HI(g) Hrxn = 53.0 kJ


What will be the value of Hrxn (in kJ) for this rxn ?

HI(g) ½ H2(g) + ½ I2(s)

(A) 26.5 (C) -26.5

(B) 7.3 (D) -53.0


Assignment 5

1. Which oxide forms a basic solution when mixed with water?

(A) K2O (C) CO2

(B) Al2O3 (D) SO3

35. Which 0.1 M solution has the highest pH?

(A) sodium carbonate

(B) sodium chloride

(C) ammonium carbonate

(D) ammonium chloride

36. Which is the strongest acid?

(A) acetic acid - (Ka = 1.8 x 10¯5)

(B) benzoic acid - (Ka = 6.3 x 10¯5)

(C) formic acid - (Ka = 1.8 x 10¯4)

(D) nitrous acid - (Ka = 6.0 x 10¯4)

37. What is the order of concentration of the ions and molecules in a nitrous acid solution?

Nitrous acid, HNO2, is a weak acid.

(A) H3O+ = NO2¯ > HNO2 > OH¯

(B) H3O+ = NO2¯ = HNO2 = OH¯

(C) HNO2 > H3O+ = NO2¯ > OH¯

(D) HNO2 > NO2¯ > H3O+ > OH¯

NChO 1998

33. A water solution of sodium carbonate, Na2CO3, has a pH greater than 7 because

(A) it contains more carbonate ions than water molecules.

(B) it contains more sodium ions than carbonate ions.

(C) sodium ions react with water.

(D) carbonate ions react with water.

34. Which species dissociates most completely in water solution?

(A) NH4+ (C) HNO3

(B) H2CO3 (D) HSO4¯


37. According to Brønsted -Lowry Theory, which of these species cannot be amphoteric?

(A) NH4+(aq) (C) NH2¯(aq)

(B) NH3(aq) (D) NH2¯(aq)

NChO 1997

34. Which acid reacts with NaOH to form sodium hypochlorite (the ingredient in household

bleach)?

(A) HOCl (C) HOClO2

(B) HOClO (D) HOClO3

35. Which of these acids is the strongest in aqueous solution?

(A) H3PO4 (C) HClO3

(B) H2SO3 (D) HOCl

37. Normal rain water has a pH of 5.6. This is best explained by the presence of

(A) nitrogen oxides.

(B) carbon dioxide.

(C) sulfur oxides.

(D) particulates.

38. In a 0.050 M solution of a weak monoprotic acid, [H+]= 1.8 x 10¯3. What is its Ka?

(A) 3.6 x 10¯2 (C) 6.7 x 10¯5

(B) 9.0 x 10¯5 (D) 1.6 x 10¯7

NChO 1996

34. According to the Brønsted-Lowry definition, a base is a substance that

(A) increases the hydroxide ion concentration in water.

(B) can react with water to form OH¯ ions.

(C) can donate an electron pair to form a covalent bond.

(D) can accept a proton from an acid.

5. What is the pH of a 0.02 M solution of KOH?

(A) 12.3 (C) 2.0

(B) 12.0 (D) 1.7

36. Which couple is not a conjugate acid-base pair?


(A) HCO3¯ and CO32¯

(B) H3O+ and H2O

(C) H2PO4¯ and PO43¯

(D) NH3 and NH2¯

37. These acids are listed in order of decreasing acid strength in water.

HI > HNO2 > CH3COOH > HCN

According to the Brønsted-Lowry theory, which anion is the weakest base?

(A) I¯ (C) CH3COO¯

(B) NO2¯ (D) CN¯

38. What is the [H+] in a 0.40 M solution of HOCl?

Substance Equilibrium Constant, Ka

HOCl 3.5 x 10¯8

(A) 1.4 x 10¯8 M (C) 1.9 x 10¯4 M

(B) 1.2 x 10¯4 M (D) 3.7 x 10¯4 M

39. Which of these salts will give a basic solution when added to water?

(A) NH4NO3 (C) Ca(NO3)2

(B) NH4C2H3O2 (D) Ca(C2H3O2)2

NChO 1995

2. When sodium oxide, Na2O, is added to water, the major products expected are

(A) Na+ and OH¯ ions

(B) Na+ ions and H2O

(C) Na+ and O2¯ ions

(D) Na+ and OH¯ ions, and O2 gas

36. At 0 °C the ion product constant of water, Kw, is 1.2 x 10¯15. The pH of pure water at this

temperature is

(A) 6.88 (C) 7.46

(B) 7.00 (D) 7.56


37. What is the [H+] in a 0.010 M solution of HCN? The equilibrium constant, Ka, for HCN

equals 6.2 x 10¯10

(A) 3.6 x 10¯3 M (C) 1.0 x 10¯7 M

(B) 2.5 x 10¯6 M (D) 6.2 x 10¯10 M

38. HCN(aq) + HCO3¯(aq)

CN¯(aq) + H2CO3(aq)

If the value of the equilibrium constant, K, is less than 1, what is the strongest base in this

system?

(A) HCN (C) CN¯

(B) HCO3¯ (D) H2CO3

40. The conjugate acid of the bicarbonate ion, HCO3¯, in H2O is

(A) H3O+ (C) OH¯

(B) CO32¯ (D) H2CO3

41. The sodium salt, NaA, of a weak acid is dissolved in water and no other substance is added.

Which of the following statements is corrected?

(A) [H+] = [A¯] (C) [A¯] = [OH¯]

(B) [H+] = [OH¯] (D) [HA] = [OH¯]

42. Which of these ions is predicted to produce the most acidic solution when dissolved in H2O?

(A) K+ (C) Co2+

(B) Ba2+ (D) Fe3+

43. When 0.10 M solutions of the solutes; HClO4, NH4Br, KOH, KCN, are arranged in order in

increasing [H+], the correct order is

(A) KOH < KCN < NH4Br < HClO4

(B) KCN < KOH < HClO4 < NH4Br

(C) HClO4 < NH4Br < KCN < KOH

(D) NH4Br < HClO4 < KOH < KCN


Assignment 6NChO Practice Problems

1985

43. The chemical reaction taking place in a dry cell may be written

Zn(s) + 2H+(aq) + 2MnO2(s)

Zn2+(aq) + 2MnO(OH).

The battery is to be discarded after 2.00 g of zinc is converted to Zn2+(aq). If 0.0100 amperes

of current is continuously drawn, for how many seconds can the battery operate?

a) [(65.4) (0.0100)] ÷ [(2) (96,500)]

b) [(2) (96,500)] ÷ [(0.0100) (65.4)]

c) [(2) (65.4) (96,500)] ÷ (0.0100)

d) [(2.00) (2) (96,500)] ÷ [(65.4) (0.0100)]

44. In the oxidation-reduction reaction

Sn4+ + 2 Fe2+ 2 Fe3+ + Sn2+ a) Sn4+ is the oxidizing agent and Fe2+ is the reducing agent.

b) Sn4+ is the reducing agent and Fe2+ is the oxidizing agent.

c) Sn4+ is the reducing agent and Fe3+ is the oxidizing agent.

d) Fe3+ is the oxidizing agent and Sn2+ is the reducing agent.

45. Given the standard reduction potentials

Cu2+ + 2e¯ Cu(s) E° = +0.34 Volt

Al3+ + 3e¯ Al(s) E° = -1.66 Volt

Calculate the standard voltage for the reaction

2Al(s) + 3Cu2+ 2Al3+ + 3Cu(s)

a) -1.22 Volt b) +2.00 Volt

c) +4.34 Volt d) +5.86 Volt


1986

46. Given the standard electrode (reduction) potentials:

Cd2+(aq) + 2e¯ Cd(s) E° = -0.40 v

Ag+(aq) + e¯ Ag(s) E° = +0.80 v

What would be the E° for a cadmium-silver cell?

a) 0.4 v b) 0.5 v

c) 1.2 v d) 2.0 v

48. A current of 10.0 amperes flows for 2.00 hours through an electrolytic cell containing a

molten salt of metal x. This results in the decomposition of 0.250 mole of metal x at the

cathode. The oxidation state of x in the molten salt isa) 1+ b) 2+ c) 3+ d) 4+

49. In a voltaic cell, oxidation occurs at the a) anode

b) cathode

c) salt bridge

d) electrode at which electrons enter from the outside

50. The free energy change for the chemical reaction that occurs in a voltaic cell when it is

discharging and producing an electric current must be

a) positive b) negative

c) zero d) unpredictable

1988

34. In the reaction

SO2 + 2 H2S 3 S + 2 H2O

a) sulfur is oxidized and hydrogen is reduced

b) sulfur is reduced and there is no oxidation

c) sulfur is reduced and hydrogen is oxidized

d) sulfur is both reduced and oxidized

35. Which group among the representative (main-group) elements contains the most powerful

oxidizing agent?

a) group I b) group III

c) group VI d) group VII


36. The following standard electrode (reduction) potentials refer to aqueous solution at 25°C.

Ni2+(aq) + 2e¯ Ni(s) E° = - 0.25 V

Cu2+(aq) + 2e¯ Cu(s) E° = + 0.34 V

Fe3+(aq) + e¯ Fe2+(aq) E° = + 0.77 V

What is the standard potential for the reaction

Cu2+(aq) + Ni(s) Cu(s) + Ni2+(aq) ?

a) 0.09 V b) 0.59 V

c) 0.86 V d) 1.02 V

37. Which ion, in solution, can be oxidized by appropriate chemical means but also can be

reduced by a different chemical reaction?

a) Fe2+ b) F¯

c) CO32¯ d) NO3¯

1989

49. Zinc reacts with dilute acid to produce H2 and Zn2+ but silver does not liberate hydrogen

from an acid. This information enables one to predict that

a) H2(g) + Zn2+(aq) 2H+(aq) + Zn(s)

b) 2 Ag(s) + Zn2+(aq) 2Ag+(aq) + Zn(s)

c) 2 Ag+(aq) + Zn(s) 2Ag(s) + Zn2+(aq)

d) 2 Ag(s) + 2H+(aq) H2(g) + 2 Ag+(aq)

50. In the electroplating of silver from cyanide solution the cathode reaction is

Ag(CN)2¯ (aq) + e- Ag(s) + 2CN¯ (aq)

How many grams of silver should be deposited by a current of 4.50 amperes in 28.0

minutes?

a) 0.141 g b) 4.23 g

c) 8.45 g d) 12.53 g


1990

17. For the reaction shown below, which statement is true? 2Fe + 3 CdCl2 2 FeCl3 + 3Cd

a) Fe is the oxidizing agent

b) Cd undergoes oxidation

c) Cd is the reducing agent

d) Fe undergoes oxidation

19. What is the potential in volts for the spontaneous reaction between the Ag/Ag2+ and Zn/Zn2+

half-cells?

Zn2+ + 2e¯ Zn E° = -0.763V

Ag+ + 1e¯ Ag E° = 0.799V

a) -2.361 b) -1.562

c) 1.562 d) 2.361

1991

47. Given the standard reduction potentials,

Cr3+ + 3e¯ Cr -0.74 V

Pb2+ + 2e¯ Pb -0.13 V

what is the standard potential, E°, for the following reaction?

2 Cr + 3 Pb2+ 2 Cr3+ + 3 Pb

a) 0.61 V b) 0.87 V

c) 1.09 V d) 1.87 V

Half-cell reaction E°

Cu2+ (aq) + 2e¯ Cu(s) -0.25 V

Ni2+ (aq) + 2e¯ Ni(s) +0.34 V

65. When two half-cells are connected using a salt bridge, a) a galvanic cell will result in which Cu is the cathode

b) a galvanic cell will result in which Cu is the anode

c) an electrolytic cell will result in which Ni is the cathode

d) an electrolytic cell will result in which Ni is the anode


1992

58. Corrosion of ships can be minimized by attaching a "sacrificial plate" of zinc to the hull.

This plate corrodes instead of the steel of the ship because a) the zinc behaves as a cathode, and is oxidized to zinc ions.

b) the zinc behaves as an anode, and is oxidized to zinc ions.

c) the steel hull behaves as a cathode, and is reduced to iron ions.

d) the steel hull behaves as an anode, and is reduced to iron ions.

59. A spoon is made the cathode in an electroplating apparatus containing a AgNO3 solution.

How many grams of Ag will be plated on the spoon if a current of 2.00 A is passed through

the apparatus for 1.90 min.?

a) 0.255 g b) 0.150 g

c) 0.128 g d) 0.0638 g

60. A cell is set up using the following reactions:

Zn | Zn2+ (0.5M) || Ni2+ (0.1 M) | NiNi2+ + 2e¯ Ni E° = -0.250 V Zn2+ + 2e¯ Zn E° = -0.763 V

What is the voltage of the cell?

a) -0.513 V b) -1.013 V

c) 0.492 V d) 0.513 V

1993

67. How many grams of cobalt metal will be deposited when a solution of cobalt(II) chloride is

electrolyzed with a current of 10. amperes for 109 minutes?

a) 0.66 b) 4.0

c) 20 d) 40


66. What voltage will be produced by the electrochemical cell?

Reduction Potentials

Pb2+ + 2e¯ Pb -0.13 V

Al3+ + 3e¯ Al -1.68 V

a) 2.97V b) 1.55V

c) -1.81V d) -2.97V

1994

46. If solid nickel metal were added to separate aqueous solutions each containing 1M

concentrations of Ag+, Cd2+, and Sn2+ ions, how many metals would plate out, based on the

given standard reaction potentials? Standard Reduction Potentials

Ag+/Ag 0.799 VSn2+/Sn -0.141 VNi2+/Ni -0.236 VCd2+/Cd -0.400 V

a) zero b) one

c) two d) three

48. Solutions of Ag+, Cu2+, Fe3+ and Ti4+ are electrolyzed with a constant current until 0.10 mol

of metal is deposited. Which will require the greatest length of time?

a) Ag+ b) Cu2+

c) Fe3+ d) Ti4+


1996

43. Use these reduction potentials to determine which one of the reactions below is spontaneous.

Reaction Reduction

Potentials, E°

Ag+ + e¯ Ag 0.800 V

Pb2+ + 2e¯ Pb - 0.126 V

V2+ + 2e¯ V - 1.18 V

a) V2+ + 2 Ag V + 2 Ag+

b) V2+ + Pb V + Pb2+

c) 2 Ag+ + Pb2+ 2 Ag + Pb

d) 2 Ag+ + Pb 2 Ag + Pb2+

44. It is possible to produce chlorine gas by electrolyzing any of these chlorine-containing

compounds under the proper conditions. Which compound will require the smallest number

of coulombs to produce one mole of chlorine?

a) Ca(OCl)2 b) NaClO2

c) KClO3 d) Mg(ClO4)2

1997

43. What is the function of H2O2 in this reaction?

6H+ + 2MnO4¯ + 5H2O2 2Mn2+ + 5O2 + 8H2O

a) catalyst b) reducing agent

c) oxidizing agent d) inhibitor

44. How much hydrogen is produced from the electrolysis of water in the same time that 2.2 L

of oxygen is formed?

a) 0.14 L b) 1.1 L

c) 2.2 L d) 4.4 L

45. Which of these changes will cause the value of the potential for this half-reaction to be less

negative? (E° = -0.28 V for the reaction.)

Co2+(aq) + 2 e¯ Co(s)

a) increasing the amount of solid Co

b) decreasing the amount of solid Co


c) increasing the concentration of Co2+(aq)

d) decreasing the concentration of Co2+(aq)

1998

40. For this reaction, E°cell = 0.79 V.

6I¯(aq) + Cr2O72¯(aq) + 14H+

3I2 (aq) + 2Cr3+(aq) + 7H2O(aq)

Given that the standard reduction potential for

Cr2O72¯(aq) 2Cr3+ (aq) is 1.33 V, what is E°red for I2(aq)?

a) +0.54 V b) -0.54 V

c) +0.18 V d) -0.18 V

41. What is the product formed at the anode in the electrolysis of 1.0 M NaNO3(aq)?

a) H2(g) b) NO2(g)

c) O2(g) d) Na(s)

42. Which of these ions is the best reducing agent?

Standard Reduction Potentials, E°

Fe3+(aq) + e¯ Fe2+(aq) +0.77 V

Cu2+(aq) + e¯ Cu+(aq) +0.15 V

a) Fe3+ b) Fe2+

c) Cu2+ d) Cu+

43. Zn(s) + Cl2(g, 1 atm)

Zn2+(aq, 1 M) + 2Cl¯(aq, 1 M)

An electrochemical cell based on this reaction has a cell voltage, E°, of 2.12 V. Which

change could make the cell voltage greater than 2.12 V?

a) add more Zn(s)

b) add more Cl¯(aq) ions

c) decrease the concentration of Zn2+(aq) ions

d) decrease the partial pressure of Cl2



1. Which of the following does NOT influence the speed of a chemical reaction?

a) concentration of reactants

b) nature of reactants

c) temperature

d) presence of a catalyst

e) none of these

2. What would cause the change in the kinetic energy diagrams as shown?

a) increasing the H

b) decreasing the temperature

c) increasing the surface area

d) addition of a catalyst

e) increasing the concentration of reactant

3. Diketahui diagram waktu vs konsentrasi untuk reaksi A B. Berapa laju dari B setelah 20

detik reaksi berjalan?

a) 0.050 mol/Ls d) 0.010 mol/Ls

b) 3.2 mol/Ls e) 9.8 mol/Ls

c) 2.2 mol/Ls


4. The reaction 3O2 2O3 is proceeding with a rate of disappearance of O2 equal to 0.60

mol/Ls. What is the rate of appearance of O3, in mol/Ls?

a) 0.60 d) 0.90

b) 0.40 e) 1.20

c) 0.10

5. A reaction has the rate law Rate = k[A]2[B]. What is the overall order of the reaction?

a) 0 b) 2 c) 1 d) 4 e) 3

6. What are the correct units for a second order rate constant?

a) mol/Ls d) L2/mol2s

b) 1/s e) mol2/L2s

c) L/mols

7. The reaction I- + OCl- IO- + Cl- is first order with respect to I- and first order with

respect to OCl-. The rate constant is 6.1 x 10-2 L/mols. What is the rate of reaction when

[I-] = 0.10 M and [OCl-] = 0.20 M?

a) 2.4 x 10-4 M/s d) 1.2 x 10-4 M/s

b) 1.2 x 10-3 M/s e) 2.4 x 10-5 M/s

c) 6.1 x 10-3 M/s

8. Sebuah reaksi dan hokum laju reaksi diberikan dibawah ini. Jika [C4H6] = 2.0 M, lajunya

adalah 0.106 M/s. Berapa laju [C4H6] = 4.0 M?

2 C4H6 C8H12 Rate = k[C4H6]2

a) 0.053 M/s d) 0.424 M/s

b) 0.212 M/s e) 0.022 M/s

c) 0.106 M/s

9. The rate law for the reaction2NO(g) + O2(g) 2NO2(g)

is Rate = k[NO]2[O2]. What happens to the rate when the concentration of NO is doubled?

a) the rate doubles d) the rate is halved

b) the rate triples e) none of these

c) the rate quadruples


10. Dibawah ini tersedia data laju alir untuk reaksi, 2A + B C. Berapa hokum laju reaksi

untuk reaksi ini?Experiment [A]o [B]o Rate (M/s)

1 2.0 M 1.0 M 0.1002 2.0 M 2.0 M 0.4003 4.0 M 1.0 M 0.100

a) Rate = k[A][B] d) Rate = k[A]2[B]2

b) Rate = k[A]2[B] e) Rate = k[B]2

c) Rate = k[A][B]2

11. The acid catalyzed decomposition of hydrogen peroxide is a first order reaction with the rate

constant given below. For an experiment in which the starting concentration of hydrogen peroxide is 0.110 M, what is the concentration of H2O2 450 minutes after the reaction

begins?2H2O2 2H2O + O2 k=1.33 x 10-4 min-1

a) 0.0961 M d) 0.00658 M

b) 0.104 M e) 0.0156 M

c) 0.117 M

12. What is the rate constant for a first order reaction for which the half-life is 85.0 sec?

a) 0.00814 sec-1 d) 0.0118 sec-1

b) 4.44 sec-1 e) 58.9 sec-1

c) 0.170 sec-1

13. What fraction of a reactant remains after 3 half-lives of a first order reaction?

a) 1/2 d) 1/8

b) 1/3 e) 1/12

c) 1/6

14. Asumsikan reaksi terjadi dengan mekanisme seperti dibawa ini. Apa hokum laju untuk

reaksi tersebut ?

A + B C Cepat

C D Lambat

a) Rate = k[A][B][C]

b) Rate = k[A]2

c) Rate = k[A][B]

d) Rate = k[A][B]/[D]


e) Rate = k[A]

15. According to collision theory, which of the following factors does NOT influence the rate of

reaction?

a) collision frequency

b) collision energy

c) collision orientation

d) collision rebound direction

e) none of these

16. What distance corresponds to the activation energy for the reaction of X to Y?

a) a d) d

b) b e) e

c) c

17. At what point on the potential energy diagram given below does the transition state

(activated complex) occur?

a) a d) d

b) b e) e

c) c


18. The rate constants, at two different temperatures, for the reaction

CH3I + Br- CH3Br + I-

are given below.

t = 30C k = 1.38 x 10-4 M-1s-1

t = 49C k = 1.21 x 10-3 M-1s-1

What is the activation energy for this reaction? R = 8.314 J/molK.

a) 92.7 kJ/mol d) 343 kJ/mol

b) 200 kJ/mol e) none of these

c) 40.3 kJ/mol

19. Which of the following is NOT true about a catalyst?

a) it speeds up the forward reaction

b) is acts as an inhibitor

c) it speeds up the reverse reaction

d) it may be homogeneous

e) it may be heterogeneous

20. In the reaction, H2 + Br2 2HBr, the step Br + H2 HBr + H is what step?

a) initiation d) propagation

b) completion e) termination

c) inhibition

21. In the reaction, H2 + Br2 2HBr, the step Br + Br Br2 is what step?

a) initiation d) propagation

b) completion e) termination

c) inhibition

22. A free radical is a chemical species that possesses

a) a positive charge

b) a negative charge

c) an unpaired electron

d) an oxygen atom

e) unconventional political views


Assessment and Code of Conduct

6.1. Instrument1. Group assignments 2. Individual assignments3. Presentation4. Lembar Tugas Mahasiswa5. Midsemester exam (written test, restricted response essay, extended response essay)6. Final exam (written test, restricted response essay, extended response essay)

1.2. Assessment

No Component Weight1. Group and individual assignments 20 %2. Presentation 10 %3. LTM 10 %4. Mid semester exam 30 %5. Final exam 30 %

Total 100 %

6.3. Grading

≥ 85 80-84.9 75-79.9 70-74.9 65-69.9 60-64.9 55-59.9 50-54.9 40 – 49.9 0-40A A- B+ B B- C+ C C- D E

6.4. Code of Conducto No cheating. Cheating will be sanctioned with “E” mark.o No sandalso No smokingo Attendance is required min 75 %. Why? Knowledge can be transferred through handout, but

“values” can’t be! So, please come and we may share good values in life.o Maximum late : 15 minutes


Chapter

6

References

[1] Ralph H. Petrucci, General Chemistry: Principles and Modern Applications, 8th Ed. Prentice Hall Inc, New York, 2001.

[2] John McMurry, Robert C. Fay, Chemistry (3rd ed.), Prentice Hall, 2001.[3] Raymond Chang, Williams College, Chemistry (7rd ed.), McGraw-Hill, 2003.


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