1. Chem101 Chapter 01
Chemical Foundations

2. What is chemistry? The science that explains:
the properties of materials
how new materials may be made
the relationship between energy and chemical reactions
how materials may be analyzed at the atomic and molecular
level (Macroscopic & Microscopic.
A key concept is that chemists look for explanations

3. 1.1Chemistry: An overview
Chemistry is fundamentally concerned with:
"How one substance changes to another"
How plants grow by absorbing water and Carbon dioxide?
How humans manufacture the proteins from the food we consume?
….. and on and on
A substance is composed of atoms, all universe is made of only 110 {different types of atoms}

4. 1.2 The Scientific Method
It is a systematic approach to research that includes:
Making Observation
Making a Prediction "Hypothesis"
Doing Experiment to test the Hypothesis
Law: summary of observed behavior
Theory: model attempt to explain

5. a number and a scale (unit)
1.3 Units of Measurement
Quantitative Measurement, consists of two parts:
a number and a scale (unit)
In 1960, an international agreement get up a system of units called International System (SI- system) based on metric system.

6. Prefixes: are used to change the size of the unit
1.3 Units of Measurement
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

7. {SI derived unit for volume is cubic meter (m3)}
1.3 Units of Measurement
Volume is not fundamental SI – unit, but very commonly used in chemistry,
{SI derived unit for volume is cubic meter (m3)}
1 m3 = (10 dm)3 = 1000 dm3 = 1000 L
Used unit in liter = 1dm3
1 L = 1dm3 = (10 cm)3 = 1000 cm3 (ml)

8. 1.4 Uncertainty in measurement
Any measurement always has some degree of uncertainty. Uncertainty depends on the precision of measuring device.
e.g., measurement of volume of a liquid using a buret:
the used liquid is about ………………….mL
If 4 different people read the same volume we might get:
Person
Result 1
22.2 2
22.1 3
22.3 4
22.0

9. 1.4 Uncertainty in measurement
You have to record the certain digits and the first uncertain digit only.
All digits together
[ certain + first uncertain]
are called
" Significant Figures"
The uncertainty in the last number must be assumed to be # 1
Volume = 22.2 ± 0.1 ml
Example 1.1:
What is the difference between the measurements 25.00mL and 25mL?

10. Precision and Accuracy
1.4 Uncertainty in measurement
Precision and Accuracy
Not Accurate
Not precise
Accuracy: it is the agreement of a particular value with the true value.
Precision: it is the agreement among several measurements of the same quantity.
Not Accurate
But precise
Accurate
and precise

11. Errors 1.4 Uncertainty in measurement
Large Random
Error
Random error: it means that a measurement has an equal probability of being high or low.
Systematic error: error accurse in the same direction each item.
Small Random
and Large Systematic
Error
Small Random
And NO Systematic
Error

12. 1.5 Significant Figures (SF) and Calculations
Rules for Counting Significant Figures:
It is important to be applied to get the uncertainty in the final results out of adding, subtracting multiplying ..etc.
Nonzero integers, count as SF.
Zeros:
- "Leading zeros” are not significant. e.g (2 SF)
- "Captive zeros” Count as s.f. e.g.: (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 unite large or small numbers in the correct sig.fig.
e.g convenient  6.0 x 10-5

13. 1.5 Significant Figures (SF) and Calculations
Rules for SF in Mathematical Operations:
Multiplication / Division: Final results have the same SF in the least precise measurement used in calculation.
e.g x 1.4 = 6.38 = (………………?)
Addition / Subtraction: Final results have the same number of decimal places as the least precise numbers
e.g = = (…………?)

14. 1.5 Significant Figures (SF) and Calculations
Note: To get the correct total SF in the final results you may round off the results.
Rules for rounding:
if the number to be removed is < 5, the preceding digit stays the same.
e.g., round 1.33 to 2 S.F.  (…………?)
Exercise 1.4:
a) 1.05 x 10-3 ÷ = (………….?)
b) 21 – 13.8 = (……………?)

15. 1.6 Dimensional Analysis 7.00 in = 17.8 cm
conversion of a given results from one system unit to an other using "Unit Factor Method" or dimensional analysis.
Means Multiply any expression by "1" will not change its value.
Exercise 1.5:
A pencil is 7.00 in long, What is its length in centimeter?
Solution:
what is the in/cm relation: 2.54cm = 1 in
which unit is needed: cm
unit factor must has cm unit as nominator.
i.e cm / 1 in = 1 [unit factor]
Multiply the length by the unit factor gives:
7.00 in x 2.54 cm /1 in = 17.8 cm
7.00 in = 17.8 cm

16. 1.6 Dimensional Analysis Note:
Sometime you have to do multi-step conversion to get correct answer.
Exercise 1.7:
A student has entered a 10.0 km race. How long is the run in miles?
Solution: km  m  yd mi
[1 km = 1000m, 1 m = 1.09yd, 1760yd = 1 mi]
Results: 10.0 km = 6.22 mi

17. 1.7 Temperature Adjust the zero difference Tc = (TF-32oF) x 5oF/ 9oC
Engineering
Science
Difference
Is complicated
Difference
Is in their zero
Conversion
Adjustment in the degree step
Adjustment in the zero
Conversion
Adjust the zero difference
Tc = (TF-32oF) x 5oF/ 9oC
TF = (T0C x 9oF/5oC) + 32oF
T(Kelvin) = T(oC)

18. 1.8 Density It is the mass per unit volume of the substance.
A property of matter that is often used by chemists.
Density =
Exercise 1.13:
A chemist finds that 25.00cm3 of a CD- cleaner has a mass of g at 20oC.
The following are the names and densities of the compounds that might be the main component:
Which of them is the most likely to be the main component of the CD-cleaner?
Solution:
Chloroform
1.492
g / cm3
At 20oC
Diethyl ether
0.714
Ethanol
0.789
Isopropyl alcohol
0.785
Toluene
0.867

19. 1.9 Classification of matter
Read (pp )
and Report (HW#2):
Define :
"Matter, Mixtures, Physical changes, Compound, and Element"
Define:
"Distillation, Filtration, and Chromatography.

20. What is this apparatus? What is its main opeation?