chemistry nya class notes and exercises part 3

8/10/2019 Chemistry NYA Class Notes and Exercises Part 3

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Email: [email protected]: f-228Phone: x311

CHAMPLAIN COLLEGE

SAINT-LAMBERT

GENERAL CHEMISTRY

202-NYA-205Winter 2012

Joel Robichaud
mailto:[email protected]://www.champlainonline.com/mailto:[email protected]


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Course Outline

nomenclature empirical & molecularformulas stoichiometry gas laws

molarity

UNIT 1:Basics

UNIT 2:

Atomic Theory

history of atomic theory the Bohr atom the modern approach(quantum theory) quantum numbers

electron configurations electron affinity

UNIT 3:Periodicity &

Chemical Reactions

electron configuration & chemicalproperties of elements ionization energy atomic and ionic size electronegativity & electron affinity

reactions of the main group elementswriting molecular & net ionic equations

UNIT 4:Chemical Bonding

analysis of ionic & covalent bonding

writing Lewis structures, resonancestructures formal charges shapes of molecules bond angles bond polarity dipole moments hybridization theory orbital diagrams

UNIT 5:Intermolecular Forces

intermolecular forces intramolecular

bonds dispersion forces, dipole-dipole forces hydrogen bonding relationship of melting & boiling point& solubility to intermolecular forcesclassification of substances

UNIT 6:Liquids & Solutions

properties of solids

phase changes & phasediagrams physical properties ofsolutions concentration units colligative properties
http://www.champlainonline.com/


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Unit III: Periodicity & Chemical Reactions(Chang, Ch. 2, 4, and 7 to 9)

Objectives:

explain how the periodic table was constructed on the basis of the periodic variation in the physical and chemicalproperties of the elements. (2.4) explain the meaning of the terms noble gases, representative elements & transition elements (d- & f-block). (2.4) explain the term isoelectronic, and write the electron configuration for ions derived from both the representativeand transition elements. (7.9 & 8.2) define the term atomic radius and explain trends (with exceptions) within the periodic table with an emphasis onthe concept of effective nuclear charge, Zeff. (8.3) define the term ionic radius and compare the sizes of ions with the neutral atoms from which they are formed. Explain how the sign and magnitude of the charge on the ion affect its radius. (8.3) classify elements as metals and non-metals according to their positions in the periodic table.(2.4) define the term ionization energy & explain trends (with exceptions) within the representative elements of theperiodic table. (8.4) define the term electron affinity and explain trends (with exceptions) within the representative elements of theperiodic table. (8.5)

use the trends in ionization energy & electron affinity to explain the difference between ionic & covalent bonding, &how the preferred mode of bonding varies with the position of the representative element in the periodic table. (8.6) (a) write equations for the reaction of oxygen with the representative elements & predict the type of bonding in theproduct. (b) write equations for the reaction of the oxides of the metals and non-metals with water (hydrolysisreactions). (c) explain the terms acidic, basic, and amphoteric oxides. (8.6) classify oxides as acidic, basic or amphoteric according to their position in the periodic table. (8.6)write the equation for the reaction of the amphoteric hydroxide of Al with an acid and a base. (8.6). identify the five types of chemical reactions that we encounter in the Chemistry NYA course and write molecular,

ionic and net ionic equations for each. (4.2 4.4) 1.Combination reactions, 2. Decomposition reactions, 3. Singlereplacement reactions, 4. Double replacement reactions, 5. Combustion of an organic molecule.


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Unit III: Periodicity & Chemical Reactions(Chang, Ch. 2, 4, and 7 to 9)

3.1 Periodic Classification of Elements(Chang, 8.2, Problems: 8.20; 8.22; 8.24; 8.26; 8.28; 8.30; 8.32)

Chemical reactivity is largely determined by the valence electrons (outermost electrons).

The non-valence electrons are referred to core electrons.

Representative elements of the same group have the same # of valence electrons.

Not all the chemical reactivity is based on electrons:

Group 4A: Carbon is a non-metalSilicon & germanium are metalloids

Tin & lead are metals

For the representative elements, they are in the highest occupied n.


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3.1 Element Representation in a Chemical Reaction

Metals: do not exist in discrete molecular units, the empirical formula is used in chemical equation(i.e. the symbol, Fe for iron).

Non-metals: Some exist as a diatomic molecule: H2, N2, O2, F2, Cl2, Br2, I2

(I Have No Bright Or Clever Friends). Carbon is C, the empirical formula is used, Noble gases are monoatomic (He, Ne, Ar, Xe, Rn).

Phosphorus is stable as a P4, Sulfur is stable as S8 (but S is often used).

Metalloids: They have complex three-dimensional networks, They are represented by the empirical formula (i.e. the symbol).


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Electron Configuration of Cations & AnionsIons derived from the representative elements:

When forming ions, they will adopt an electron configuration ns2 np6.

They will lose electrons from their highest occupied n shell. The ions will now have a noble gas configuration.

Na: [Ne] 3s1 Na+: [Ne]Ca: [Ar] 4s2 Ca2+: [Ar]

Al: [Ne] 3s2 3p1 Al3+: [Ne]

Ex.

They will gain electrons in their highest partially filled n shell. The ions will have a noble gas configuration.

H: 1s1 H-: 1s2 or [He]

F: 1s2 2s2 2p5 F-: 1s2 2s2 2p6 or [Ne]

O: 1s2 2s2 2p4 O2-: 1s2 2s2 2p6 or [Ne]

N: 1s2 2s2 2p3 N3-: 1s2 2s2 2p6 or [Ne]

Ex.

Na+, Al3+, F-, O2-, or N3- all have the same electron configuration.They are said to be isoelectronic.

For cations:

For anions:


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Cations derived from transition metals:

Note carefully: Mn: [Ar] 4s2 3d3 Mn2+: [Ar] 3d3

The electrons are first removed from the highest ns, then from the (n-1) d orbitals.

Since most transition metals form more than one cation, they will not necessarilyadopt a noble gas configuration.

The electrons are removed from the highest shell.

Electron Configuration of Cations & Anions


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3.1.1 Exercises:1. Write the electron configuration of the following ions. Are they stable ions?

They are isoelectronic with which neutral element?

Ion Electron Configuration Stable Ion: Y/N Isoelectronic with:

N2-

Mg+

O2-

P3-

He+

H-

Ca2+

K+


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3.2 Periodic Variation in Physical Properties(Chang, 8.3, Textbook Problems: 8.38; 8.40; 8.44; 8.46)

Effective Nuclear ChargeThe effective nuclear charge (Zeff) is the actual charge felt by an electron.

Zeff= Z

is the shielding constant (equal to the # of core electrons for a neutral atom)

Core electrons are on average closer to the nucleus than valence electrons & they shieldthe valence electrons from the nucleus more than valence electrons from one another.

3.2.1 Exercises:1. Calculate the Zeffof the following elements:

a) Na b) H

c) Li d) Cs

e) N f) Cl

g) Ca h) I


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Trends...Horizontal Trend:

Vertical Trend:

Z ZeffLi

Na

K

Z ZeffC

N

O

F

remains the same,

Zeffincreases from left to right.

increases,Z

effremains the same.


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Atomic RadiusAtomic radius: is one-half the distance between 2 nuclei in 2 adjacent metal atoms

or in a diatomic molecules.

Horizontal trends:

Trends...

The radius decreases from left to right.

Electrons are added on the same n shell

(average distance should be about the same). The effective nuclear charge (Zeff) increases(the larger the Zeff, the stronger the hold onthese electrons, the smaller the radius).

Vertical trends: The radius increases from top to bottom.

The valence electrons are added in a higher n shell(n determines the average distance from the nucleus).

The effective nuclear charge (Zeff) remains the same

(does not affect the trend in a group).


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Atomic Radius


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3.2.2 Exercises:

1. Arrange the following groups of atoms in order of their increasing atomic radius (without

looking at the chart above):a) Cl, Na, Al, Mg

b) I, F, Br, At

c) K, Rb, F, B, Be

d) P, Si, N


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Ionic RadiusIt is measured byX-ray diffraction.

Formation of Anion:

F + e- F-

(Fluorine has a radius of 75 pm while fluoride has a radius of 136 pm)

Formation of a Cation:

Li Li+ + e-

(lithium has a radius of 150 pm while lithium cation has a radius of 60 pm)

To determine the relative size, create a table that compares Z with the # of electrons.

the radius increases. As electrons are added, there is moreelectron-electron repulsion, so that each electron experiences aslightly smaller attraction to the nucleus (Z is the same).

the radius decreases. As electrons are removed, there is lesselectron-electron repulsion, so that each electron experiences aslightly greater attraction to the nucleus (Z is the same).

Ex.

Ex.


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3.2.3 Exercises:

1. Arrange the following isoelectronic ions according to their increasing size: Cl-, K+, S2-, P3-, Ca2+

and explain the arrangement by using the total # of electrons and atomic # in your explanation.


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Ionization energy (kJ/mol): energy required to remove an electron from agaseous atom in its ground state.

Ionization Energy(Chang, 8.4, Textbook Problems: 8.52; 8.54; 8.56)

X (g) + energy X+ (g) + e-

There are different values depending on whether the 1st, 2nd, 3rd electron is removed:

X (g) + energy X+ (g) + e- 1st ionization energyX+ (g) + energy X2+ (g) + e- 2nd ionization energyX2+ (g) + energy X3+ (g) + e- 3rd ionization energy

The 2nd ionization energy is always greater than the 1st since you are removing anelectron from something that is already positive.

From the ionization energies it is possible to find the # of valence electrons(there is a sudden rise in the ionization energies when you remove

core electrons versus valence electrons).


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Ionization Energies


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Trends...

Vertical trend:

First ionization energy decreases down a group (as the radius gets larger,removing an electron becomes easier).

The effective nuclear charge (Zeff) is the same and therefore has no effect.

Horizontal trend:

First ionization energy increases across a period (as the radius gets smaller,removing an electron becomes more difficult).

The effective nuclear charge (Zeff) increases and therefore it becomes harder

to remove an electron (greater pull towards the nucleus).


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The 1st ionization energy from group3Ais lower than the 1st ionization energy from 2A:

Group 2A: ns2

Group3A: ns2np1

Exceptions from Group 2A & 3A:

A p orbital is higher in energy than a s orbital, therefore it requires less energyto remove an electron from it even though the Zeff is higher

(i.e. the p electrons are not held as tightly).

The 1st ionization energy from group 6Ais lower than the 1st ionization energy from 5A:

Group 5A:

Group 6A:

In group 6Ayou have 2 electrons in the same orbital, so that thereis more electron-electron repulsion. In group 5A, all of the

electrons are in different orbitals.

Examination of the electron configuration:

Examination of the orbital box diagram:

Exceptions from Group 5A & 6A:

ns np

ns np


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3.4 Electron Affinity(Chang, 8.5, Textbook Problems: 8.62; 8.64)

Electron affinity is measured by the energy released or absorbed when an electronis accepted by an atom in the gaseous state to form an anion.

F (g) + e- F- (g) H = -328 kJ/mol

Note that in this case the energy is negative because energy is released(it would have required energy to remove an electron therefore).

The more negative the #, the more energy is released when an electron is accepted.

Ex.


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3.4 Electron AffinityTrends...

Vertical trend:

Horizontal trend:

The electron affinity decreases when going down a group.

The effective nuclear charge (Zeff) remains the same, but as theradius increases, the electrons on the outer shell are further fromthe nucleus, hence gaining an electron will be harder.

The electron affinity increases across a period.

The effective nuclear charge (Zeff) increases, and as the radiusdecreases, the electrons on the outer shell are closer to thenucleus, hence gaining an electron is easier.

There are numerous exceptions to this trend but it serves as a guide.


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3.5 Electronegativity(Chang: Section 9.5, Textbook Problems...)

Electronegativity: the measure of the ability of a bonded atom to attract the electronsin the bond from other atoms to which it is bonded.

The trend follows generally the same one as electron affinity:

Horizontally: Increases from left to right.

Vertically: Decreases from top to bottom.


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3.5.1 Exercises:1. Consider the following elements: N, B, Be, K and Fa) Arrange in the above elements in order of increasing atomic radius

b) Arrange the above elements in order of increasing ionization energyc) Arrange the above elements in order of increasing electronegativityd) Explain your order in 1b) and 1c).

2. Consider the following elements: Ca, F, S, Cl and Pa) Arrange in the above elements in order of increasing atomic radiusb) Arrange the above elements in order of increasing ionization energyc) Arrange the above elements in order of increasing electronegativityd) Explain your order in 2b) and 2c).

3. Consider the following ions: N3-, Na+, Mg2+, F- and O2-.Arrange the above ions in order of increasing ionic radius & explain.


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4. Consider the following ions: Si4-, Cl- and Ca2+.Arrange the above ions in order of increasing ionic radius & explain.

5. Which has the larger radius: Si2+ or Si4+? Explain.

6. Which has the larger radius: F- or Br-? Explain.

7. Which has the larger radius: Na+ or Mg2+? Explain.

8. Which has the larger radius: Fe2+ or Fe3+? Explain.

3.5.1 Exercises:


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9. Match each of the following elements with its ionization energy. Explain your choice and explainany irregularities to the general trend:

Elements: Li; Be; B; C; N; O; F; Ne:Ionization Energy Values (kJ|mol) : 2080; 1681; 1402; 1314; 1086; 900; 800; 560.

10. Explain why the 2nd ionization energy of Rb is much greater than the 2nd ionization energy of Sr.

11. The values for the 1st, 2nd, 3rd ionization energies of an unknown element are found to be as follows:Ionization Energy: 1st 2nd 3rd

kJ/mol: 897 1782 14820

In which A group of the periodic table would you expect to find this elements? Explain your answer.

3.5.1 Exercises:


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3.6 Chemical Bonds Between Atoms in a Compound(Chang, 9.2 & 9.4, Textbook Problems...)

There are3 types of bonds between atoms:

Ionic Bonds, Non-Polar Covalent Bonds & Polar Covalent bonds

Ionic Bonds:Ionic bond: a bond between positively & negatively charged atoms

(usually involves a metal & a non-metal).

Usually the difference in electronegativity will be greater or equal to 2.

Electrostatic forces will hold ions together.

No individual molecules exist.


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Non-polar covalent bonds:

3.6 Chemical Bonds Between Atoms in a Compound

Non-polar covalent bond: a bond which is the result of an equal sharing ofelectrons between 2 non-metals.

Polar Covalent bonds:

Polar covalent bond: a bond which is the result of an unequal sharing of

electrons, most often between 2 non-metals.

The electronegativity will differ by no more than 0.3.

Individual molecules exists

The difference in electronegativity will be roughly around 0.3 to 2.

Individual molecules exists.


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3.6.1 Exercises:1. Classify the following species as having ionic, polar covalent & non-polar covalent bonds.a) SrS b) K2O c) HCl

d) H2 e) HBr f) NaCl

g) F2 h) Cl2 i) HF

j) H2O k) NCl3 l) PH3

m) KH n) NH3 o) BaO

p) CO2 q) CsF r) CH4


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3.7 Types of Reactions(Chang,Textbook Problems...)

Combination Reactions: elements or compounds combine together.

A + B C

Decomposition Reactions: a compound breaks into elements or compounds.

C A + B

Oxidation or Burning of Organic Compounds:

(organic compounds have C, H & sometimes O)

Reactions in aqueous solutions:

Single Replacement Reactions:

A + BC B + ACD + BC C + BD

Double Replacement Reactions:

AB + CD AD + CB

a reaction with oxygen & heat.


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Writing Chemical Equations

There are 3 ways to write reactions:

Complete Molecular Equations (CME): the formulas of compounds are writtenin molecular form.

Complete Ionic Equations (CIE): all soluble strong electrolytes are written in ionic form

[Soluble salts, strong acids (ex. HCl, HBr, HI, HNO3,HClO4, H2SO4, strong bases (group 1A & 2A hydroxides)

all gases, insoluble solids, non & weak-electrolytesare written in molecular form.

Net Ionic Equations (NIE): any substance present that is not reacting isnot written in this equation.


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3.8 Aqueous Reactions(Chang, Textbook Problems...)

Is a Single Replacement Reaction:

Is a reaction in aqueous solution.

The reactivity of halogens decrease as you go down in the group:

Halogen Displacement:

D + BC BD + C

The physical states of the halogens:

F2 & Cl2 are gases

Br2 is a liquidI2 is a solid

The radius increases as you go down, hence the ability to gain an electron decreases.

A more reactive halogenwill replace a less reactive halogen from its halide.

Importance of discerning the difference between a halogen (X2) and a halide (X-)

and how each is described in various chemical equations (CME vsCIE).


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3.8.1 Exercises:1. Write the CME, CIE and NIE for the following reaction: Cl2 (g) + NaBr (aq)

Step 1: Is there a reaction?

Step 2: What are the molecular products?Step 3: Balance the equationStep 4: Complete the CIEStep 5: Complete the NIE

Cl2 (g) + NaBr (aq)

CMECIENIE

2. Complete the following:

a) Br2 (l) + NaI (aq) CMECIENIE

b) Cl2 (g) + KI (aq) CMECIE

NIE


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c) Cl2 (g) + NaF (aq) CME

CIENIE

d) I2 (s) + NaCl (aq) CMECIENIE

e) F2 (g) + NaBr (aq) CMECIENIE

f) Br2

(l) + NaF (aq) CMECIENIE

g) F2 (g) + NaCl (aq) CME

CIENIE

3.8.1 Exercises:


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Hydrogen & Metal Displacement (Chang, Textbook Problems...):

Is a Single Replacement Reaction:


The reactivity follows the activity series:

A + BC AC + B

Li; K; Ba; Ca; Na; Mg; Al; Zn; Ni; Pb; H2; Cu; Ag

(see back of your periodic table)

The new product AC may or may not be soluble in water, you need to checkthe solubility table (see back of the periodic table).

3.8 Aqueous Reactions

Elements on the left can replace elements on the right.


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3.8.1 Exercises:1. Write the CME, CIE and NIE for the following reaction Na (s) + HCl (aq) Step 1: Is there a reaction?Step 2: What are the molecular products?Step 3: What is the solubility of the new product AC?Step 4: What is the state of pure B?Step 3: Balance the equationStep 4: Complete the CIE:Step 5: Complete the NIE:

2. Complete the following:a) Ca(s) + H2SO4 (aq) (CME)CIENIE

b) Cu (s) + AgNO3 (aq) (CME)CIE

NIE

c) Zn (s) + Cu(NO3)2 (aq) (CME)CIENIE

d) Mg (s) + Ni(NO3)2 (aq) (CME)

CIENIE


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Precipitation Reactions (Chang, Textbook Problems...)

Is a Double Replacement Reaction:


AB + CD AD + CB

AB & CD are 2 solutions with ions floating around:

When mixed together, 2 ions may combine to form a precipitate (i.e. solid).

If combined and there is no precipitate, then there is no reaction.



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3.8.2 Exercises:

1. Write the CME, CIE and NIE for the following reaction NaCl (aq) + AgNO3 (aq) Step 1: What are the molecular products?Step 2: What is the state of these products?Step 3: Is there a reaction?Step 3: Balance the equationStep 4: Complete the CIE:Step 5: Complete the NIE:

2. Complete the following:

a) NaCl (aq) + AgNO3 (aq) CMECIENIE

b) LiCl (aq) + H3PO4 (aq) CMECIENIE


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c) Mg(ClO3)2 (aq) + (NH4)3PO4 (aq) CME

CIENIE

d) Al2(SO4)3 (aq) + LiBr (aq) CMECIE

NIE

e) AgF (aq) + Cu(NO3)2 (aq) CMECIENIE

f) Ni(NO3)2 (aq) + Na2CO3 (aq) CMECIENIE

3.8.2 Exercises:


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1. Write the CME, CIE and NIE for the following reaction HCl (aq) + NaOH (aq)

Step 1: What are the molecular products?Step 2: What is the state of these products?Step 3: Balance the equationStep 4: Complete the CIE:Step 5: Complete the NIE:

2. Complete the followinga) KOH (aq) + H2SO4 (aq) (CME)CIENIE

b) H2SO3 (aq) + Ba(OH)2 (aq) (CME)

CIENIE

c) H2CO3 (aq) + LiOH (aq) (CME)CIENIE

3.8.3 Exercises:


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d) NaOH (aq) + H3PO4 (aq) (CME)CIE

NIE

e) Ba(OH)2 (aq) + H3PO4 (aq) (CME)CIENIE

f) Fe(OH)2 (s) + H2SO4 (aq) (CME)

CIENIE

g) Fe(OH)3 (s) + HCl (aq) (CME)CIENIE

h) HClO3 (aq) + Ca(OH)2 (s) (CME)CIENIE

i) H2CO3 (aq) + Mg(OH)2 (s) (CME)CIE

NIE

3.8.3 Exercises:


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Reactions of acids with carbonates (Chang, 4.3):



There is always a reaction: the H+ of the acid combines with the carbonate(CO3

2- or HCO3-) to form H2O & CO2.


AB + CD AD + CB

Note: H2CO3 is first formed but isnt stable & decomposes into H2O & CO2.

3.8.4 Exercises:1. Complete the following:

a) HBr (aq) + Na2CO3 (aq) (CME)CIE

NIE

b) HCl (aq) + NaHCO3 (aq) (CME)CIENIE

c) HNO3 (aq) + CaCO3 (s) (CME)

CIENIE


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Reaction of acids with acetates (Chang, 4.1):




There is always a reaction, the H+ of the acid combines with the acetate (C2H3O2-) to

form acetic acid.

AB + CD AD + CB

Note: acetic acid is not ionic (i.e. weak acid) & will not separate into its ions for the CIE or NIE.

1. Complete the followinga) HNO3 (aq) + NaC2H3O2 (aq) (CME)CIENIE

b) HCl (aq) + Ca(C2H3O2)2 (aq) (CME)CIE

NIE

3.8.5 Exercises:


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3.8 Reaction of bases with ammonium salts(Chang, 4.3)



There is always a reaction: the OH- of the base will always combine with theammonium (NH4

+) to form H2O & NH3.

AB + CD AD + CB

Note: NH4OH is actually formed which isnt stable & decomposes into H2O & NH3

1. Complete the following:a) KOH (aq) + NH4Cl (aq) (CME)CIE.NIE

b) Ca(OH)2 (aq) + NH4Br (aq) (CME)CIE

NIE

3.8.6 Exercises:


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Reactivity increases as we go down in a group (i.e. the radius increases).

3.9 Chemical Properties of the Representative ElementsGroup 2A the alkali earth metals:

They react with water to form a metal hydroxide & hydrogen gas:

M (s) + 2 H2O (l) M(OH)2 (aq or s) + H2 (g)

Exception: Be doesnt reactwith waterMg reacts only with steam (very hot water)

They react with oxygen to form the oxide:

2 M (s) + O2 (g) 2 MO (s)

Be & Mg react with oxygen only at high temperatures

The oxide can react with water to form a hydroxide:

MO (s) + H2O (l) M(OH)2 (aq or s)

BeO & MgO are unreactive

Ex.

Exception:

Ex.

Exception:

Ex.


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Boron is a metalloid & the rest are metals: we will look at aluminum.

3.9 Chemical Properties of the Representative ElementsGroup 3A

Aluminum will not react with water.

Aluminum reacts with oxygen to form the oxide:

4 Al (s) + 3 O2 (g) 2 Al2O3 (s)

The oxide doesnt reactwith water.

Aluminum oxide is amphoteric (i.e. it has acidic & basic properties).

Aluminum hydroxide [Al2O3 + 3 H2O 2 Al(OH)3] can react with acids & bases.

Ex.

3.9.1 Exercises:1. Complete the following:

a) Al(OH)3 (s) + HCl (aq) (CME)CIENIE

b) Al(OH)3 (s) + NaOH (aq) NaAl(OH)4 (aq) (sodium aluminate) (CME)

CIENIE


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C is a non-metal, Si & Ge are metalloids, Sn & Pb are metals.

The elements dont react with water.

Carbon reaction with oxygen:

2 C (s) + O2 (g)

2 CO (g)C (s) + O2 (g) CO2 (g)

The oxide reacts with water:

CO2 (g) + H2O (l) H2CO3 (aq)

Ex.

Ex.


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Chlorine reacts with oxygen:

7 Cl2 (g) + O2 (g) 7 Cl2O7 (l)

The oxide can react with water to form an acid:

Cl2O7 (l) + H2O (l) 2 HClO4 (aq)

Halogens can react with hydrogen:

X2 (g, l or s) + H2 (g) 2 HX (aq)


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Summary:

Group Number Reactions

with O2

Reaction of Oxides

with Water

1A M2O MOH

2A (Be & Mg are

unreactive)

MO M(OH)2

3A (Al only) Al2O3 Not reactive

4A (C only) CO & CO2 H2CO3 (from CO2)

5A (N & P only) NO, NO2,

N2O, N2O4,

N2O5

P4O6, P4O10

HNO3 (from N2O5)

H3PO3 (from P4O6)

H3PO4 (from P4O10)

6A (S only) SO2, SO3 H2SO3 (from SO2)

H2SO4 (from SO3)

7A Cl2O7 HClO4


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3.10 Combination Reactions(Chang, Textbook Problems...)

To determine the product when combining a neutral metal with a neutral non-metal,look at the stable ion from the metal and that from the anion:

Ca (s) + O2 (g)

Na (s) + Cl2 (g)

Hg (l) + O2 (g)

When combining non-metals together, you must know the products(some come from the reactions of the representative elements):

C (s) + O2 (g) CO2 (g)

H2

(g) + O2

(g) H2O (l)

Sometimes you can combine compounds & elements,again you must know the product in this case:

CaO (s) + CO2 (g)

SO2 (g) + O2 (g)


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3.11 Decomposition(Chang, Textbook Problems...)

These reactions are the reverse of combination reactions. Energy is needed to decompose stable compounds.

CaCO3 (s)

NaCl (s)

HgO (s)

H2O (l)


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3.12 Oxidation (Burning/Combustion) of Organic Compounds(Chang, Textbook Problems...)

Note: organic compounds are made of C & H, but they may also contain O & N.

When they react with O2 they form CO2 (g) & H2O (l):

CH4 (g) + O2 (g)

CH3OH (l) + O2 (g)

C2H5OH (l) + O2 (g)

C2H6 (g) + O2 (g)


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End of unit exercises:Problems on Equation Writing

1. Complete and balance the following equation and classify as: combination, decomposition,

burning of organic compound, single replacement or double replacement.

a) H2SO4 (aq) + KOH (aq) b) H3PO4 (aq) + Mg(OH)2 (s) c) CaCl2 (aq) + Na2CO3 (aq) d) HCl (aq) + KHCO3 (aq) e) S8 (s) + O2 (g) f) Si (s) + O2 (g) g) Al (s) + O2 (g) h) Li2O (s) + H2O (l) i) CO2 (g) + H2O (l) j) Na (s) + H2O (l)

k) Na (s) + H2 (g) l) Ba (s) + Cl2 (g) m) H2 (g) + Cl2 (g) n) K2CO3 + HCl (aq) o) AgNO3 (aq) + BaCl2 (aq) p) (NH4)2CO3 (aq) + HCl (aq) q) Li (s) + O2 (g) r) C2H6 (g) + O2 (g) s) HgO (s) + heat t) CaI2 (aq) + Br2 (l) u) BaCl2 (aq) + H2SO4 (aq) v) NH4NO3 (aq) + NaOH (aq)

w) Ca(CH3CO2)2 (s) + HCl (aq) x) Na2CO3 (aq) + H2SO4 (aq) y) KOH (aq) + H3PO4 (aq) z) Ba(OH)2 (aq) + H2SO4 (aq) aa) Mg (s) + H2SO4 (aq) bb) MgO (s) + H2O (l) + heat cc) NaCl (s) + heat dd) H3PO4 (aq) + Mg(s) ee) N2O5 (s) + H2O (l) ff) P4O6 (s) + H2O (l) gg) Cl2 (aq) + CaBr2 (aq) hh) Na2O (s) + H2O (l) ii) Al (s) + HCl (aq) jj) CaCO3 + heat


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2. Write the CME, CIE & NIE for the following reactions. All soluble reactants are in aqueoussolutions.

a) Sulphuric acid with barium hydroxide b)Barium chloride & sodium sulfatec) Sodium carbonate & nitric acid d) Silver nitrate & ammonium chloridee) Ammonium hydroxide & sulphuric acid f) Aluminum hydroxide & perchloric acidg) Potassium carbonate & strontium chloride h) Aluminum & hydrochloric acidi) Potassium acetate & sulphuric acid j) Calcium sulfite & sodium hydroxidek) Magnesium metal & sulphuric acid l) Potassium carbonate & hydrochloric acid

m) Aluminum metal with calcium hydroxide n) Phosphoric acid & potassium hydroxideo) Potassium hydroxide with ammonium bromide

3. Sodium metal reacts with atmospheric oxygen to form compound A, compound A reacts with waterto give compound B, compound B reacts with carbon dioxide to give compound C and water,compound C reacts with barium chloride to give solid D and NaCl and solid D reacts with

hydrochloric acid to give water, compound E and barium chloride. Identify A, B, C, D, E and write theequation for each reaction.

End of unit exercises:


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4. How would calcium oxide react with:

a) Water

b) Sulfuric acidc) How would the product in 4a) react with:

i) Hydrochloric acidii) Carbon dioxideiii) Ammonium chloride

5. Write the equation for the reaction of each of the following elements with oxygen.

a) Barium b) Sulphur

6. Write the equation for the reaction of the products of 5) with water.

7. How would the products of 6) react with sodium hydroxide?

8. How would the products of 6) react with hydrochloric acid?

9. How would the products of 6) react with sodium carbonate?

10. Give the balanced equations for the reaction of sodium with each of the following:

a) Hydrogen b) Oxygen c) Bromine d) Water



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11. What would you expect to happen if you added concentrated sodium hydroxide solution to asolution of aluminum chloride?

12. Write the CME, CIE and NIE for the following:a) Aqueous NaOH is added to AlCl3 until a white precipitate appearsb) Excess NaOH is added to the precipitate from a) until the precipitate disappears

13. For the following elements: Sulphur, chlorine, phosphorus, potassium, carbon, aluminuma) Write the formula of its oxide. List only the highest oxidation state oxides (the one with the most

oxygens)b) Classify each oxide as acidic, basic or amphoteric

14. Predict whether a reaction will happen or not. If a reaction occurs, complete & balance the

equation.

a) NaOH (aq) + H2SO4 (aq) b) H2 (g) + O2 (g) c) C5H12 (l) + O2 (g) d) H2O (l) (electrolysis) e) Al (s) + KCl (aq) f) K (s) + Cl2 (g) g) AgF (aq) + Cu(ClO3)2 (aq) h) AlBr3 (aq) + (NH4)3PO4 (aq) i) F (g) + KBr (aq)


chemistry nya class notes and exercises part 3

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