1. I. Using Measurements (p. 44 - 57)
CH. 2 - MEASUREMENT
I. Using Measurements
(p )
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2. A. Accuracy vs. Precision
Accuracy - how close a measurement is to the accepted value
Precision - how close a series of measurements are to each other
ACCURATE = CORRECT
PRECISE = CONSISTENT
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3. B. Percent Error Indicates accuracy of a measurement your value
accepted value
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4. B. Percent Error % error = 2.9 %
A student determines the density of a substance to be 1.40 g/mL. Find the % error if the accepted value of the density is 1.36 g/mL.
% error = 2.9 %
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5. C. Significant Figures Indicate precision of a measurement.
Recording Sig Figs
Sig figs in a measurement include the known digits plus a final estimated digit
2.35 cm
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6. C. Significant Figures Counting Sig Figs (Table 2-5, p.47)
Count all numbers EXCEPT:
Leading zeros
Trailing zeros without a decimal point -- 2,500
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7. Counting Sig Fig Examples
C. Significant Figures
Counting Sig Fig Examples
4 sig figs
3 sig figs
3. 5,280
3. 5,280
3 sig figs
2 sig figs
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8. C. Significant Figures (13.91g/cm3)(23.3cm3) = 324.103g 324 g
Calculating with Sig Figs
Multiply/Divide - The # with the fewest sig figs determines the # of sig figs in the answer.
(13.91g/cm3)(23.3cm3) = g
4 SF
3 SF
3 SF
324 g
C. Johannesson

9. C. Significant Figures 3.75 mL + 4.1 mL 7.85 mL 3.75 mL + 4.1 mL
Calculating with Sig Figs (con’t)
Add/Subtract - The # with the lowest decimal value determines the place of the last sig fig in the answer.
3.75 mL mL
7.85 mL
3.75 mL mL
7.85 mL
224 g
+ 130 g
354 g
224 g
+ 130 g
354 g
 7.9 mL
 350 g
C. Johannesson

10. C. Significant Figures Calculating with Sig Figs (con’t)
Exact Numbers do not limit the # of sig figs in the answer.
Counting numbers: 12 students
Exact conversions: 1 m = 100 cm
“1” in any conversion: 1 in = 2.54 cm
C. Johannesson

11. C. Significant Figures Practice Problems 5. (15.30 g) ÷ (6.4 mL)
4 SF
2 SF
= g/mL
 2.4 g/mL
2 SF g g
 18.1 g
18.06 g
C. Johannesson

12. D. Scientific Notation 65,000 kg  6.5 × 104 kg
Converting into Sci. Notation:
Move decimal until there’s 1 digit to its left. Places moved = exponent.
Large # (>1)  positive exponent Small # (<1)  negative exponent
Only include sig figs.
C. Johannesson

13. Mathematics and Chemistry
Section
Mathematics and Chemistry
1.1
Scientific Notation
A number in the form a x 10n is written in scientific notation where 1 ≤ a < 10, and n is an integer. (An integer is a whole number, not a fraction, that can be positive, negative, or zero.)
When moving the decimal point to the right, you reduce the exponent when using scientific notation.
Right – REDUCE
When moving the decimal point to the left, you make the exponent larger when using scientific notation.
LEFT – LARGER
Common powers of ten include 100 = 1, 101 = 10, 102 = 100, etc.

14. D. Scientific Notation Practice Problems 7. 2,400,000 g 8. 0.00256 kg
9. 7  10-5 km
 104 mm
2.4  106 g
2.56  10-3 kg km
62,000 mm
C. Johannesson

15. D. Scientific Notation Calculating with Sci. Notation
(5.44 × 107 g) ÷ (8.1 × 104 mol) =
Type on your calculator:
EXP EE
EXP EE
ENTER
EXE
5.44 7
8.1 ÷ 4 =
= 670 g/mol
= 6.7 × 102 g/mol
C. Johannesson

16. E. Proportions Direct Proportion Inverse Proportion y x y x
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17. II. Units of Measurement (p. 33 - 39)
CH. 2 - MEASUREMENT
II. Units of Measurement
(p )
C. Johannesson

18. Warm-Up Problems Sig. figs?: 0.030800, 8000, 250., .450 450kg = _____g
.56mm = _____m
If the density of gold is 19.3 g/mL. If you have 58 grams of gold, what is the volume? (d=m/v) (remember sig figs!)
The moon is 250,000 miles away. How many feet is it from Earth?(1 mi =5280 ft)
C. Johannesson

19. Warm-Up Problems Sig. figs?: 0.030800; 8000; 250. ; 0.450
450kg = _____g
.56mm = _____m
If the density of gold is 19.3 g/mL. If you have 58 grams of gold, what is the volume? (d=m/v) (remember sig figs!)
The moon is 250,000. miles away. How many feet is it from Earth?(1 mi = 5280 ft)
C. Johannesson

20. A. Number vs. Quantity Quantity - number + unit UNITS MATTER!!
C. Johannesson

21. B. SI Units Quantity Symbol Base Unit Abbrev. Length l meter m Mass m
kilogram kg
Time t
second s
Temp T
kelvin K
Amount n
mole
mol
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22. B. SI Units Prefix Symbol Factor mega- M 106 kilo- k 103 BASE UNIT ---
100
deci- d
10-1
centi- c
10-2
milli- m
10-3
micro- 
10-6
nano- n
10-9
pico- p
10-12
C. Johannesson

23. M V D = C. Derived Units 1 cm3 = 1 mL 1 dm3 = 1 L
Combination of base units.
Volume (m3 or cm3)
length  length  length
1 cm3 = 1 mL
1 dm3 = 1 L
D = M V
Density (kg/m3 or g/cm3)
mass per volume
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24. D. Density
Mass (g)
Volume (cm3)
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25. Problem-Solving Steps
1. Analyze
2. Plan
3. Compute
4. Evaluate
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26. D. Density V = 825 cm3 M = DV D = 13.6 g/cm3 M = (13.6 g/cm3)(825cm3)
An object has a volume of 825 cm3 and a density of 13.6 g/cm3. Find its mass.
GIVEN:
V = 825 cm3
D = 13.6 g/cm3
M = ?
WORK:
M = DV
M = (13.6 g/cm3)(825cm3)
M = 11,200 g
C. Johannesson

27. D. Density D = 0.87 g/mL V = M V = ? M = 25 g V = 25 g 0.87 g/mL
A liquid has a density of 0.87 g/mL. What volume is occupied by 25 g of the liquid?
GIVEN:
D = 0.87 g/mL
V = ?
M = 25 g
WORK:
V = M D
V = g
0.87 g/mL
V = 29 mL
C. Johannesson

28. III. Unit Conversions (p. 40 - 42)
CH. 2 - MEASUREMENT
III. Unit Conversions
(p )
C. Johannesson

29. Warm-Up What is the formula for density?
What units are used to express density?
C. Johannesson

30. Warm-Up Convert the following to sci-notation 65000000g .0000765km
780mL
mol
Calculate the percent error if you were supposed to get 2.6g but you actually got 3.5 g. (check notes for formula)
C. Johannesson

31. Warm-Up Identify the following as homogenous or heterogenous mixtures:
Orange juice
Soda water
Sand with different colored grains
Raisin bran cereal
Mixed up Kool-Aid
Soil
C. Johannesson

32. Warm-Up Convert the following to sci-notation 65000000g .0000765km
780mL
mol
Calculate the percent error if you were supposed to get 2.6g but you actually got 3.5 g. (check notes for formula)
C. Johannesson

33. A. SI Prefix Conversions
1. Find the difference between the exponents of the two prefixes.
2. Move the decimal that many places.
To the left
or right?
C. Johannesson

34. A. SI Prefix Conversions=
532 m = _______ km
0.532
NUMBER
UNIT
NUMBER
UNIT
C. Johannesson

35. A. SI Prefix Conversions
Symbol
Factor
mega- M
106
kilo- k
103
BASE UNIT
---
100
deci- d
10-1
move left
move right
centi- c
10-2
milli- m
10-3
micro- 
10-6
nano- n
10-9
pico- p
10-12
C. Johannesson

36. A. SI Prefix Conversions
0.2
1) 20 cm = ______________ m
2) L = ______________ mL
3) 45 m = ______________ nm
4) 805 dm = ______________ km 32
45,000
0.0805
C. Johannesson

37. B. Dimensional Analysis
The “Factor-Label” Method
Units, or “labels” are canceled, or “factored” out
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38. B. Dimensional Analysis
Steps:
1. Identify starting & ending units.
2. Line up conversion factors so units cancel.
3. Multiply all top numbers & divide by each bottom number.
4. Check units & answer.
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39. B. Dimensional Analysis
Lining up conversion factors:
= 1
1 in = 2.54 cm
2.54 cm cm
1 =
1 in = 2.54 cm
1 in in
C. Johannesson

40. B. Dimensional Analysis
How many milliliters are in 1.00 quart of milk? (1L=1.057qt) qt mL
1.00 qt
1 L
1.057 qt
1000 mL
1 L
= 946 mL 
C. Johannesson

41. B. Dimensional Analysis
You have 1.5 pounds of gold. Find its volume in cm3 if the density of gold is 19.3 g/cm3. (1kg=2.2lbs) lb
cm3
1.5 lb
1 kg
2.2 lb
1000 g
1 kg
1 cm3
19.3 g
= 35 cm3
C. Johannesson

42. B. Dimensional Analysis
How many liters of water would fill a container that measures 75.0 in3? (2.54cm=1 in)
in3 L
75.0 in3
(2.54 cm)3
(1 in)3
1 L
1000 cm3
= 1.23 L
C. Johannesson

43. B. Dimensional Analysis
5) Your European hairdresser wants to cut your hair 8.0 cm shorter. How many inches will he be cutting off? (1 in = 2.54 cm) cm in
8.0 cm
1 in
2.54 cm
= 3.2 in
C. Johannesson

44. B. Dimensional Analysis
6) Taft football needs 550 cm for a 1st down. How many yards is this? (1 in = 2.54 cm) (1ft = 12in) (1yd= 3ft) cm yd
550 cm
1 in
2.54 cm
1 ft
12 in
1 yd
3 ft
= 6.0 yd
C. Johannesson

45. B. Dimensional Analysis
7) A piece of wire is 1.3 m long. How many 1.5-cm pieces can be cut from this wire? cm
pieces
1.3 m
100 cm
1 m
1 piece
1.5 cm
= 86 pieces
C. Johannesson