1. Which of the following is a pure substance?
Sweat
Beef stew
Coffee
Apple juice
Ice
Answer: E

2. Your Turn!
Coffee is a homogeneous mixture. When you add sugar to it and the sugar dissolves…
the coffee becomes a heterogeneous mixture.
the coffee is still a homogeneous mixture.
the coffee, which used to be a pure compound, is no longer a pure compound.
the coffee, which used to be an element, is no longer an element.
the sugar reacts with water to form a new compound.
Answer: B

3. Which of the following is a heterogeneous mixture?
Seawater
Chicken soup
Coffee
Hydrogen peroxide
Ice
Answer: B

4. Your Turn! Which one of the following represents a physical change?
when treated with bleach, some dyed fabrics change color
grape juice left in an open unrefrigerated container turns sour
when heated strongly, sugar turns dark brown
D. in cold weather, water condenses on the inside surface of single pane windows
E. when ignited with a match in open air, paper burns
Answer: D

5. Which of the following represents a chemical change?
Freezing water to make ice cubes
Dry ice evaporating at room temperature
Toasting a piece of bread
Dissolving sugar in hot coffee
Crushing an aluminum can
Answer: C

6. Which of the following is a chemical property?
Squeezing oranges to make orange juice
Melting butter for popcorn
Separating sand from gravel
Hydrogen peroxide decomposing to water and oxygen
Ozone as a gas at room temperature
Answer: D

7. Your Turn! Which of the following is an extensive property? Density
Melting point
Color
Temperature
E. Mass
Answer: E 7

8. It is a solid at 25 °C. It has a density of 1.38 g/cm3.
Which of the following would NOT be considered an intensive property describing an unknown sample?
It is a solid at 25 °C.
It has a density of 1.38 g/cm3.
It melts at 62.0 ° C.
It has a volume of 0.52 cm3.
It is shiny.
Answer: D

9. Which of the following is NOT a base unit?
Meter
Kilogram
Liter
Kelvin
Second
Answer: C

10. Convert °C into K and °F
Find the equation that relates the given quantity to the quantity you want to find
Given:
Find:
Equation:
40.00 °C K
K = °C
Because the equation is solved for the quantity you want to find, substitute and compute
K = °C
K =
K = K
Find the equation that relates the given quantity to the quantity you want to find
Given:
Find:
Equation:
40.00 °C °F
Solve the equation for the quantity you want to find
Substitute and compute

11. Temperatures in Death Valley can rise above 120 ° F
Temperatures in Death Valley can rise above 120 ° F. What is this temperature in Kelvin?
393 K
–153 K
322 K
234 K
Answer: C

12. Rules for Significant Figures
All non-zero numbers are significant.
e.g., has 4 sig. figs.
Zeros between non-zero numbers are significant.
e.g., 20,089 or × 104 has 5 sig. figs
Trailing zeros always count as significant if number has decimal point
e.g., 500. or 5.00 × 102 has 3 sig. figs 12

13. Rules for Significant Figures
Final zeros on number without decimal point are NOT significant
e.g., 104,956,000 or × 108
has 6 sig. figs.
Final zeros to right of decimal point are significant
e.g., has 3 sig. figs.
Leading zeros, to left of first nonzero digit, are never counted as significant
e.g., or 1.2 × 10–4 has 2 sig. figs.

14. Learning Check
How many significant figures does each of the following numbers have?
Scientific Notation # of Sig. Figs.
413.97
0.0006
161,000
3600.
× 102 5
6 × 10–4 1 7
1.61 × 105 3
3.600 × 103 4

15. Your Turn! How many significant figures are in 19.0000? 2 3 4 5 6
Answer: E

16. Your Turn! How many significant figures are in 0.0005650850?7 8 9 10 11
Could be rewritten as  10-4
Answer: A

17. Which of the following numbers has four significant figures?
0.003
0.7180
0.508
Answer: B

18. The data is both accurate and precise.
A student measures the mass of a penny four times and records the following data. What can be said about the data if the actual mass of the penny is g?
Trial
Number
Mass, g 1
2.5104 2
2.5106 3
2.5102 4
2.5109
The data is both accurate and precise.
The data is neither accurate nor precise.
The data is accurate, but not precise.
The data is not accurate, but it is precise.
Answer: D

19. Learning Check
Round each of the following to three significant figures. Use scientific notation where needed.
37.459
7.665
37.5 or 3.75 × 101
5.43 × 106
133 or 1.33 × 102
8.77 × 10–4
7.66

20. Your Turn!
Round to four significant figures and express using scientific notation.
5.64  10-2
5.000  10-3
5.645  10-4
5.645  10-3
Answer: E

21. Significant Figures in Calculations
Multiplication and Division
Number of significant figures in answer = number of significant figures in least precise measurement
e.g., × 31.4 ×
4 sig. figs. × 3 sig. figs. × 5 sig. figs. = 3 sig. figs.
e.g., ÷ 0.008
4 sig. figs. ÷ 1 sig. fig. = 1 sig. fig.
= 5620 = 5.62×103
= 700 = 7×102

22. Your Turn!
Give the value of the following calculation to the correct number of significant figures.
1.212
1.2 1
Answer: D

23. Significant Figures in Calculations
Addition and Subtraction
Answer has same number of decimal places as quantity with fewest number of decimal places.
e.g.,
319.5
4 decimal places
1 decimal place
3 decimal places
336.9
397 –
0 decimal places
2 decimal places
0 decimal place
124

24. Learning Check
For each calculation, give the answer to the correct number of significant figures.
10.0 g g g =
°C – °C =
327.5 m × 4.52 m =
g ÷ mL =
11.3 g or
1.13 × 101 g
0.004 °C or 4 × 10–3 °C
1.48 × 103 m
g/mL or
6.627 × 10–1 g/mL

25. Your Turn! When the expression,–
is evaluated, the result should be expressed as:
424.06
424.1
424
Answer: C

26. Your Turn! When the expression,–
is evaluated, the result should be expressed to the:
tenths place
hundredths place
thousandths place
ten-thousandths place
hundred-thousandths place
Answer: C

27. Learning Check
For the following calculation, give the answer to the correct number of significant figures
= 2 × 10–4 m/s2
= cm3/s

28. Exact Numbers
Exact numbers have an unlimited number of significant figures.
A number whose value is known with complete certainty is exact
Exact counting of discrete objects … atoms
Integral numbers that are part of an equation
eg. radius = diameter/2.0000…
Defined quantities ( … cm = 1.000… m)
Some conversion factors are defined quantities, while others are not.
In the instances in this slide, the numbers are exact and therefore have an unlimited number of significant figures.

29. Your Turn! 36.00 has four sig. figs. The conversion is exact.
Express the answer to the following with the correct number of significant figures:
3 ft.
3.0 ft
3.00 ft.
3.000 ft.
ft.
36.00 has four sig. figs. The conversion is exact.
So the answer has four
sig. figs.
Answer: D

30. Your Turn!
For the following calculation, give the answer to the correct number of significant figures.
179 cm2
1.18 cm
151.2 cm
151 cm
cm2
Answer: D

31. Calibration and Measurement
Read the water level with the correct number of significant figures.
Read the length of the metal bar with the correct number of significant figures.
Ans. _____________
A) 5 mL
B) 5.3 mL
C) 5.32 mL
D) mL
E) mL
A) 20 cm
B) 15 cm
C) 15.0 cm
D) cm
E) cm
Read the temperature with the correct number of significant figures.
A) 87°C
B) 87.2°C
C) 87.20°C
D) °C
E) °C
5.3; 15.00; 87.20; 15.0
Read the length of the metal bar with the correct number of significant figures.

32. Perform the Following Calculations to the Correct Number of Significant Figures

33. Perform the Following Calculations to the Correct Number of Significant Figures

34. Calculate the following with the correct number of significant figures.2
1.4
2.2
1.36
2.23
Answer: C

35. Using Dimensional Analysis
Example: Convert m to mm.
Relationship is 1 mm = 1 × 10–3 m
Can make two conversion factors
Since going from m to mm use one on left.
= 97 cm

36. Learning Check Example: Convert 3.5 m3 to cm3.
Start with basic equality 1 cm = 0.01 m
Now cube both sides
Units and numbers
(1 cm)3 = (0.01 m)3
1 cm3 = 1 × 10–6 m3
Can make two conversion factors or
3.5 × 106 cm3

37. Your Turn!
The Honda Insight hybrid electric car has a gas mileage rating of 56 miles to the gallon. What is this rating expressed in units of kilometers per liter?
1 gal = L 1 mile = km
1.3 × 102 km L–1
24 km L–1
15 km L–1
3.4 × 102 km L–1
9.2 km L–1
Answer: B

38. Your Turn!
The volume of a basketball is in3. Convert this to mm3.
1.101  10-2 mm3
7.104  106 mm3
7.104  104 mm3
1.101  104 mm3
1.101  106 mm3
Answer: B

39. What is the density of a solution that has a mass of 13
What is the density of a solution that has a mass of 13.5 g and a volume of 15.8 mL?
1.17 g/mL
0.213 g/mL
4.69 g/mL
0.854 g/mL
Answer: D

40. Learning Check 19.3 g/cm3 Another student has a piece of gold with a
A student weighs a piece of gold that has a volume of cm3 of gold. She finds the mass to be 212 g. What is the density of gold?
19.3 g/cm3
Another student has a piece of gold with a
volume of 1.00 cm3. What does it weigh?
19.3 g
What if it were 2.00 cm3 in volume?
38.6 g

41. Which of the following has the largest density?
A material that has a mass of 10.0 g and a volume of L
A material that has a mass of 5.00 g and a volume of cm3
A material that sinks in ethanol but floats on water
Answer: C

42. Decide if a ring with a mass of 3. 15 g that displaces 0
Decide if a ring with a mass of 3.15 g that displaces cm3 of water is platinum
Write down the given quantities and the quantity you want to find
Given:
Find:
Equation:
mass = 3.15 g
volume = cm3
density, g/cm3
Find the equation that relates the given quantity to the quantity you want to find
Solve the equation for the quantity you want to find, check the units are correct, then substitute and compute
Compare to accepted value of the intensive property
Density of platinum = 21.4 g/cm3
therefore not platinum

43. Learning Check
1. Glass has a density of 2.2 g/cm3. What is the volume occupied by 35 g of glass?
2. What is the mass of 400. cm3 of glass?
16. g
8.8  102 cm3

44. Your Turn!
Titanium is a metal used to make artificial joints. It has a density of 4.54 g/cm3. What volume will a titanium hip joint occupy if its mass is 205 g?
9.31 × 102 cm3
B × 101 cm3
C × 10–2 cm3
D × 10–3 cm3
E × 10–1 cm3
Answer: B

45. Your Turn!
A sample of zinc metal (density = 7.14 g cm–3) was submerged in a graduated cylinder containing water. The water level rose from cm3 to cm3 when the sample was submerged. How many grams did the sample weigh?
1.16 × 103 g
1.33 × 103 g
23.5 g
D × 102 g
E g
Answer: D