chem101 chapter 01

1Dr. M. A. MorsyChemistry Dept., KFUPM

Chem101Chem101

Chapter 01Chapter 01Chem101Chem101

Chapter 01Chapter 01Chemical Chemical

FoundationsFoundations

Morsy CHEM 101-Chapter 1

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Chapter 1-Preview This chapter covers the following:

•Scientific Methods

•Measurements used in the laboratory– Units, uncertainty, significant figures

•Handling numerical results– Operational rules, unit Factor, …

•Classification of Matter– Element, compound, mixture, …


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Introduction • Chemistry is all around you all the time

– body, plants, cars, … etc.

• Chemistry is important to historians– Dinosaurs disappearance ????? {meteor}.– Decline of Roman Empire ?????? {lead

poisoning}.

• Chemistry is important in determining a person’s behaviour– Statesville Prison (Illinois) (violent) !!!!!!!!– Insects communications

(Pheromones) !!!!!!!!!!


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1.1Chemistry: An overview

• It is fundamentally concerned with: "How one substance changes to

another"1.How plants grow by absorbing

water and Carbon dioxide?2.How humans manufacture the

proteins from the food we consume?

3.….. and on and on

Goal: “Understand the concepts of Chemistry”


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1.1Chemistry: An overview

• Watermost common and

important substance, is composed of two types of

atoms, Hydrogen and Oxygen.

O

H

H

HOH

Electric Current

Reaction

• "Scientists"Scientists are usually excellent

problem solvers because they have to master the scientific

approach or “Scientific Method”


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1.2 The Scientific Method

It is a systematic approach to research that includes:– Define the problem– Perform experiment and collect

data– Enough data may led to

"Hypothesis"

Law: summary of observed behavior

Theory: model attempt to explain


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1.3 Units of Measurement

Quantitative Measurement, consists of two parts:

a numbernumber and a scalescale (unit)

• In 1960, an international agreement get up a system of units called International System (SI- system) based on metric system.

Quantity Unit Abreviation Mass Kilogram Kg Length Meter m Time Second s Temperature Kelvin k Current Ampere A Amount oh sub Mole Mol Luminous int. Candela cd


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Prefixes: are used to change the size of the unit

Table 1.2 Prefixes Used with SI Units

Prefix Symbol Meaning

Tera- T 1012

Giga- G 109

Mega- M 106

Kilo- k 103

Deci- d 10-1

Centi- c 10-2

Milli- m 10-3

Micro- 10-6

Nano- n 10-9

Pico- p 10-12



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• Volume is not fundamental SI – unit, but very commonly used in chemistry,{SI derived unit for volume is cubic meter

(m3)}

Used unit in liter = 1dm3

1 m3 = (10 dm)3 = 1000 dm3 = 1000 L

1 L = 1dm3 = (10 cm)3 = 1000 cm3 (ml)



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1.4 Uncertainty in measurement

Any measurement always has some degree of uncertainty. Record the certain digits and the first uncertain digit only.

[ certain + first uncertain]The total numbers of the digits are

called " Significant Figures"

•e.g., Volume = 22.2 ± 0.1 ml

Example 1.1:What is the difference between the measurements 25.00mL and 25mL?


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•Precision and Accuracy

1.4 Uncertainty in measurement

•Errors

•Random error:

•Systematic error:


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Rules for Counting Significant Figures:

• Nonzero integers are countable as SF.• Zeros:

- "Leading zeros” are not significant. e.g. 0.0025 (2 SF) - "Captive zeros” Count as s.f. e.g.: 1.008 (4 SF)

- "Trailing zeros” count as s.f. eg. : 100 = 1.00 X 102 (3 SF)

• Exact numbers have an infinite number of SF

e.g. 10 experiment, 5 apples, 8 books … so on. .. • Exponential notation:

it is used to express large or small numbers in the correct SFe.g. 0.000060 convenient 6.0 x 10-5

1.5 Significant Figures (SF) and Calculations


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Rules for SF in Mathematical Operations:

• Multiplication / Division: Final results have the same SF in the least precise measurement used in calculation.

• Addition / Subtraction: Final results have the same number of decimal places as the least precise numbers.

1.5 Significant Figures (SF) and Calculations


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Note:Sometime you have to do

multi-step conversion to get correct answer.

1.6 Dimensional Analysis

conversion of a given results from one system unit to an other using "Unit Factor Method" or dimensional analysis.


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1.7 TemperatureEngineeringScience

DifferenceIs complicated

DifferenceIs in their zero

Tc = (TF-32oF) x 5oF/ 9oC TF = (T0C x 9oF/5oC) + 32oF T(Kelvin) = T(T(Kelvin) = T(ooC) + 273.15C) + 273.15


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1.8 Density

volume

massDensity

A property of matter that is often used by chemists.

volume

massDensity


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1.9 Classification of matter

Read (pp. 26-30)

and Report (HW#2):

• Define :Matter, Mixtures, Physical changes, Chemical Changes,Compound, and Element

• Define:Distillation, Filtration, and Chromatography


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Chapter One:

chem101 chapter 01

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