1. Metric system
Measurements
Significant figures
Relationships
Factor Label Method

2. SYSTEM OF MEASUREMENTS (SI)

3. SI Base Units

4. Derived SI Units Combinations of SI base units form derived units.
pressure is measured in kg/m•s2, or pascals

5. Temperature can be measured using three different units

6. Conversion between T units
°F = 9/5 °C + 32 OR °F = 1.8 °C + 32
K = °C

7. T _ _ G _ _ M _ _ K H D _ d c m _ _ μ _ _ n _ _ p _ _ f
e i e i e e e e i i a i e
r g g l c k c n l c n c m
a a a o t a i t l r o o t
o i i o o
1 kg = 1000 g
1 dm = 1x108 nm
1 kJ = 1x105 cJ
1 cL = μL or 1x104 μL

8. Accuracy and Precision

9. Three students perform the same experiment:
The density of the metal is g/mL
Density values (g/mL)
Joy
Taylor
Simon
Trial 1
2.4563
2.2846
4.2867
Trial 2
1.6798
2.2798
4.2904
Trial 3
4.7893
2.2901
4.2896

10. Accuracy and Precision, continued
Percentage Error
Percentage error is calculated by subtracting the accepted value from the experimental value, dividing the difference by the accepted value, and then multiplying by 100.

11. Sample Problem
A student measures the mass and volume of a substance and calculates its density as 1.40 g/mL. The correct, or accepted, value of the density is 1.30 g/mL. What is the percentage error of the student’s measurement?

12. Use of Numbers Exact numbers Accuracy Precision
1 dozen = 12 things for example
Accuracy
how closely measured values agree with the correct value
Precision
how closely individual measurements agree with each other

13. Use of Numbers Significant figures
digits believed to be correct by the person making the measurement
Exact numbers have an infinite number of significant figures
= 1 dozen
because it is an exact number!!!!

14. Significant Figures - Rules
Use of Numbers
Significant Figures - Rules
Leading zeroes are never significant
has three significant figures
Trailing zeroes only significant if after decimal point.
has five significant figures
Use scientific notation to remove doubt
2.40 x 103 has 3 significant figures
2.400x103 has 4 significant figures
2400 has only two significant figures.

15. Use of Numbers Imbedded zeroes are always significant
has five significant figures

16. Use of Numbers Multiplication & Division rule Easier of the two rules
Product has the smallest number of significant figures of multipliers

17. Sample Problem. Calculate the density of a substance with a mass of 14
Sample Problem. Calculate the density of a substance with a mass of g and a volume of 10.3 mL

18. Use of Numbers Addition & Subtraction rule
More subtle than the multiplication rule
Answer contains smallest decimal place of the addends.

19. Sample problem Determine the perimeter of a piece of paper of 27
Sample problem Determine the perimeter of a piece of paper of cm long and 6.92 cm wide.

20. Sample Problem
How many significant figures are in each of the following measurements?
a g
b cm
c. 910 m
d L
e kg

21. Chapter 2
Direct Proportion
Two quantities are directly proportional to each other if dividing one by the other gives a constant value.

22. Chapter 2
Direct Proportion

23. Inverse Proportion
Two quantities are inversely proportional to each other if multiplying one by the other gives a constant value.

24. Chapter 2
Inverse Proportion

25. The Unit Factor Method
Simple but important method to get correct answers in word problems.
Method to change from one set of units to another.

26. The Unit Factor Method fractions represent unit factors
1 ft = 12 in becomes or

27. The Unit Factor Method
Example: Express 9.32 meters in micrometers.

28. The Unit Factor Method
Example: Express 627 milliliters in L.

29. The Unit Factor Method
Example: Express 45.8 kg in mg.

30. Density conversions
Example: A 20.0 g irregular solid is introduced in a graduated cylinder. The level of water inside the graduated cylinder when from 20.0 mL to 23.3 mL. Calculate the density of the solid.

31. Density conversions
Example: What volume will occupy a liquid with a mass of 15.7 g and a density of 1.34g/mL?

32. Density conversions
Example: Calculate the mass of a gas that occupies 1.5 L and it has a density of g/mL?