1. Chapter 1 Chemical Foundations
AP Chemistry

2. Objectives Recall units of measure Describe uncertainty in measurement
Use scientific notation for numbers
Apply significant figure rules

3. Units of Measure SI Base Units Mass Kilogram – kg
1 kilogram is about 2.20 pounds
Length
Meter – m
1 meter is about 3 feet

4. Units of Measure Time Second – s
The time needed for a cesium-133 atom to perform 9,192,631,770 complete oscillations.
Temperature
Kelvin – K
273 K = 0 degrees C
Amount
Mole – mol
1 mol = 6.022x1023 particles

5. Units of Measure Current Ampre – A Luminous Capacity Candela – cd
First five are the most commonly used in chemistry

6. Volume Volume is not an SI Base Unit
Metric system
Powers of 10
1 Liter is 1/1000 of a cubic meter
1 Liter (L) = 1000 cm3 = 1000 mL

7. Cubic Meter
Liter
Milliliter

8. Volume?
Uncertainty is in the last digit.

9. Accuracy and Precision
The nearness of a measurement to its accepted value
Precision
The agreement between numerical values
You can be precise without being accurate

10. Loss of accuracy due to systematic errors
Accurate & Precise
Precise
Neither
Loss of accuracy due to systematic errors
Error in same direction every time
Random Error give erratic results
Poor technique

11. Significant Figures
All known digits plus one estimated digit in a measurement

12. What is the length?
2 Sig. Fig
1 Known Digit
1 Estimated Digit

13. Significant Figures Rule #1 All Nonzero digits are significant
Ex mL
Ex s

14. Significant Figures Rule #2 “Captive Zeros”
Zeros appearing between nonzero digits are significant
Ex g =

15. Significant Figures Rule #3 “Leading Zeros”
Zeros appearing in front of nonzero digits are not significant
Ex g
Takes care of unit changes

16. Significant Figures Rule #4 “Ending Zeros”
Ending zeros are significant if there is a decimal place
Ex m
Ex m
Ex m
is much more precise than 40000

17. What is the length?

18. Significant Figures Rule #5 “Exact Numbers”
Exact number have an unlimited number of significant figures
Exact numbers are counting numbers or definitions
2 cars or 1000g/1kg

19. Significant Figures Rule #6 “Scientific Notation”
All numbers that come before the x10n are significant
Must be in proper form
Ex. 3.33x105
Ex. 2.04x10-4

20. Rounding 5 and larger round up 4 and smaller round down
Round the following
to 2 SF =
to 4 SF =
to 3 SF =
to 2 SF =

21. Addition and Subtraction w/ SF
The answer must have the same number of digits to the right of the decimal as there are in the measurement having the fewest digits to the right of the decimal point
Ex m + 15 m =
Number of SF’s does not matter!

22. Multiplication and Division w/ SF
The answer can have no more SF’s than are in the measurement with the fewest total SF’s
Ex. 55 m / s =

23. Scientific Notation
A method of representing very large or very small numbers
M x 10n
M is a number 1 or larger and less than 10
n is an integer (positive or negative)
All digits in M are significant (If in proper form)

24. Converting to Sci. Notation
Move decimal so that M is between 1 and 10
Determine n by counting the number of places the decimal point was moved
Moved to the left, n is positive
Moved to the right, n is negative

25. Examples
340,000,000 =
5.04x105 = =
2.212x10-4 =

26. Sci. Notation on Calculators
Enter digits in you calculator using the EE key.
For TI 83’s it is the 2nd of the comma
For TI 30’s it is a key
Saves key strokes
Fewer OOR mistakes
3.4x106 = 3.4E6
7.4x10-5 = 7.4E-5

27. Sci. Notatation Math Operations
Multiply and Divide
Multiply or divide first number
Add exponents (Multiply)
Subtract exponents (Divide)
Addition and Subtraction
Exponents must be the same
Then add or subtract first number
Exponents stay the same

28. Calculations 3.0x105 + 4.0x105 = 4.0x103 – 2.0x102 =

29. Objectives Recall metric prefixes
Convert numbers from one unit to another
Describe different temperature scales
Explain density and perform calculations
Classify matter into groups

30. The Metric System A system based on powers of ten Uses SI Units
Allows easy work with both large and small numbers
Prefixes tell us which power of 10 we are using

31. SI Prefixes (10x larger) Page 9 in your book
Tera
Giga
Mega
Kilo
Hecto
Deca
Base T G M k h da
1012
109
106
103
102
101
100
1000
100 10 1

32. SI Prefixes (10x smaller).1
.01
.001
100
10-1
10-2
10-3
10-6
10-9
10-12
Base
Deci
Centi
Milli
Micro
Nano
Pico d c m μ n p

33. Conversions To convert between units set up conversion factors
Ratios of equality

34. Convert 67 kg to g

35. Convert 450 cL to dL

36. Convert 3.4x108 ng to kg

37. Converting From Metric To English
Find ratios that are true
Page 18 has some equivalents

38. Convert 763 cm to yd

39. Convert 1.2 mi/hr to ft/s

40. Convert 3.8 m2/hr to cm2/s

41. Temperature Many different temp. scales
All 0 marks based on different ideas
0 ºF Coldest saltwater stays a liquid
0 ºC Normal Freezing Point of water
0 K Molecular motion stops
1 K = 1 ºC = 1.8 ºF

43. Temperature Conversion
Temp K = Temp C
Temp C = Temp K – 273
0 ºC = 273 K
If you need any others look up the equ.
TC= (TF – 32)(5/9)
TF = TC(9/5) + 32

44. Density Ratio of mass to volume Density = __Mass__ Volume
Periodic Trend
Units
Solids – g/cm3
Liquids – g/mL
Gases – g/L

45. Density Determination
Mass is determined on a balance
Volume is measured in two ways
Regular objects can be measured
All objects can use water displacement

46. Density Physical Property Can be used to identify a substance
Lead Iron 7.87
Magnesium Zinc 7.13
Copper 8.96

47. Example: A metal cube has sides measuring 3. 00 cm
Example: A metal cube has sides measuring 3.00 cm. It has a mass of g. What is the density? What is the metal?

48. Density Physical Property Can be used to identify a substance
Lead Iron 7.87
Magnesium Zinc 7.13
Copper 8.96

50. Homework
p.33 #'s 33a-f,36a-d,42 47,57,68