1. Chemical Foundations
Chapter 1

2. The Scientific Method Summary of observed (measurable) behavior
Ex: law of conservation of mass
Observation
Hypothesis
Experiment
Theory (model)
Law
Theory
Modified
As needed
Prediction
A Theory (model) attempts to explain why it happens
Experiment

3. The Scientific Method Qualitative Quantitative Overview:
Deals with descriptions
Data can be observed but not measured
Colors, textures, smells etc.
Qualitative -----Quality
Deals with numbers
Data which can be measured
Length, Height, volume, weight, speed, time, temp
Quantitative-----Quantity
Example: Oil Painting
Blue & green paint
Gold frame
Masterful brush strokes
10” x 14”
surface area 140 in2
Weight: 8.5 pounds

4. Units of Measurement (1.3)
SI System: based on the metric system and units derived from the metric system.
Physical Quantity
Name of Unit
Abbreviation
Mass
Kilogram kg
Length
Meter m
Time
Second s
Temperature
Kelvin k
Electric Current
Ampere A
Amount of substance
Mole
mol
Luminous intensity
Candela cd

5. Units of Measurement (1.3)
Symbol
Prefix
Factor G
giga
109 M
mega
106 k
kilo
103 h
hecto
102 da
deka
101
BASE d
deci
10-1 c
centi
10-2 m
milli
10-3 μ
micro
10-6 n
nano
10-9

6. Units of Measurement (1.3)
Volume: is not a fundamental SI unit but is extremely important in chemistry. Volume can be derived from length.

7. Units of Measurement (1.3)
Mass vs. Weight
Remember MASS IS NOT THE SAME AS WEIGHT!
Mass is a measure of the resistance of an object to a change in its motion.
Weight is the response of mass to the force of gravity.

8. Uncertainty in Measurement (1.4)
Uncertainty: the uncertainty of measurement depends on the precision of the measuring device.
Report any observed measurements by recording all the certain digits plus the first uncertain digit.
20.15 ml
20.1 is certain 0.05 is uncertain

9. Precision and Accuracy (1.4)
Accuracy: agreement of a particular value with the accepted value.
Precision: agreement among several measurements of the same quantity (reproducibility).

10. Precision and Accuracy (1.4)
Random Error: equal probability of being high or low.
Systematic Error: error that occurs in the same direction each time.

11. Significant Figures & Calculations (1.5)
Scientific Notation
98,500,000 = ?
9.85 x 107
64,100,000,000 = ?
6.41 x 1010
= ?
2.79 x 10-8
4,200,000 = ?
4.2 x 106

12. Significant Figures & Calculations (1.5)
Rules for counting Significant Figures:
1. Nonzero integers always count!
2. Zeroes (3 classes):
a. Leading zeroes do not count (place holders)
b. Captive zeroes do count
c. Trailing zeroes are if there is a decimal point
3. Exact numbers (counting or from definitions)

13. Significant Figures & Calculations (1.5)
Rules for Significant Figures in calculations:
1. For multiplication or division: the resultant is the same as the LEAST precise number in the calculation.
2. For addition or subtraction: the resultant is the same number of decimal places as the least precise measurement in the calculation.
3. Rounding: DO NOT round until all calculations are completed. Use only the first number to the right of the last significant figure.

14. Significant Figures & Calculations (1.5)
Example:
12.11
18.0
31.123
31.1

15. Dimensional Analysis (1.6)
Unit Factor Method/Dimensional Analysis: converting a given result from one system of units to another.
Rules for Dimensional Analysis:
Start with what value is known, proceed to the unknown.
Draw the dimensional lines.
Insert the unit relationships.
Cancel the units.
Do the math, include units in answer.

16. Temperature (1.7) Fahrenheit Celsius Kelvin 32 ˚F 212 ˚F 180˚F 100 ˚C
Boiling point of water
32 ˚F
212 ˚F
180˚F
100 ˚C
0 ˚C
100˚C
373 K
273 K
100 K
Freezing point of water
Notice that 1 kelvin = 1 degree Celsius

17. Temperature (1.7) Tf = Tc x 9oF/5oC + 32o F Tc = 5oC/9oF(Tf – 32o F)
Tk = Tc

18. Density (1.7)
Recall that you can measure either the volume or the mass of an object. Density is a property that describes the relationship between these two measurements.

19. Density (1.7)
Compound
Density in g/cm3 at 20o C
Chloroform
1.492
Diethyl ether
0.714
Ethanol
0.789
Isopropyl alcohol
0.785
Toluene
0.867
A chemist has an unknown solution that he wants to identify. He measured out exactly ml (cm3) of the substance and found that it has a mass of g at 20 C.
Density = g/25.00 cm3 = g/cm3

20. Classifying Matter Mixtures (a variable composition)
A homogeneous mixture is the same throughout with visibly indistinguishable parts. (Solutions)
A heterogeneous mixture is one that has visibly distinguishable parts.

21. Classifying Matter
Substances, on the other hand, cannot be separated into different kinds of matter
by physical means such as sorting, filtering, heating, or cooling. (ex: Table salt)
Some substances, like silver, contain only one kind of matter. These substances are called elements.

22. Classifying Matter Matter Homogenous Heterogeneous Physical Means
Pure Substances
Compounds
Elements
Chemical Means