# Review - Chapter 1

Chem I | Chem II AP
1) Which of the following cannot be an exact number? 3 eggs 12 mL of water in a 20 mL cylinder 12 roses 6 pencils
2) Round 20.589958 to 4, 3 and 2 significant figures, respectively. 20.59, 20.5, 20 20.58, 20.5, 20 20.60, 20.6, 21 20.59, 20.6, 21
3) The solution to (22.41 + 0.464) x 999 / 18.465 is 1237 1237.32 1.24 x 103 1.2 x 104
4)
Calculate the mass of the earth in pounds if its mass is 3.7 x 1024 kg.
3.7 x 1024 kg x
 2.2 lb 1 kg
= 8.1 x 1024 lb
5)
What are the dimensions, in metric units, for a linebacker who is 76.0 inches and 245 pounds?
76.0 in x
 2.54 cm 1 in
= 193 cm x
 1 m 100 cm
= 1.93 m
245 lbs x
 1 kg 2.2 lb
= 111 kg x
 1000 g 1 kg
= 1.11 x 105 g
6)
How many cubic centimeters are there in a cube whose edge is 4.2 yards in length?
4.2 yd x
 36 in 1 yd
x
 2.54 cm 1 in
= 384.048 cm on each side
 V = lwh = (384.048)3 = 5.6644 x 107 = 5.7 x 107 cm3 (with 2 sig figs)
7)
58.0°F = ? °C
 5/9 (°F - 32) = °C 5/9 (58 - 32) = 14.4°C
8)
Calculate the density, in kg/L, of a block of wood 2.5 ft x 18 in x 36 in that weighs 646 lbs.

There are two steps to this problem: change the mass to kg and the volume to L, then use the mass and volume to calculate density. Let's look at the unit conversions first:

Mass:646 lbs x
 1 kg 2.2 lb
= 293.636 kg
Volume:
 2.5 ft = 30 in V = lwh
V = 30 in x 18 in x 36 in = 19440 in3 19440 in3 x
 2.543 cm3 13 in3
x
 1 mL 1 cm3
x
 1 L 1000 mL
= 318.5645 L
Density:D =
 M V
=
 293.636 kg 318.5645 L
= 0.921749 = 0.92 kg/L (with 2 sig figs)
9) Which of the following is a pure substance? an egg sea water bronze copper
10) Which of the following is a homogeneous mixture? an egg kool-aid oil and vinegar copper
11) Which one of the following is the least desirable for separating sand and water? freezing decanting evaporation heating
12) All of the following are pure substances, except: NaCl zinc 14 k gold carbon monoxide
13) Which is a physical change? baking cookies dissolving of Zn in HCl precipitation of solid from ions dissolving of NaCl in water
14) Which is not a physical property? oxidation of metal solubility melting point density
15) Determine the sum of: 145.321 + 2.4 147 147.7 147.721 150 When adding and subtracting, round to the least number of places past the decimal.
16) Which response lists all of the following properties of sulfur which are physical properties? I. It reacts with hydrogen when heated II. It is yellow solid at room temperature. III. It is soluble in carbon disulfide. IV. Its density is 2.97 g/mL. V. It melts at 112°C. I, II, IV, V II, III, IV II, III, IV, V II, IV, V
17) The following properties describe zinc. Which one(s) is/are chemical properties? I. It is grey-white metal II. It corrodes upon prolonged contact with moist air III. Its density is 7.14g/cm3 IV. It melts at 419°C V. It conducts electricity. IV, V II II, V V
18) Which response includes only chemical changes? I. Souring of milk II. Digestion of food III. Condensation of steam IV. Melting of silver V. Burning of coal I, II, V I, II, III I, III III, IV
19) Which response lists only physical changes? I. Evaporation of water II. Fermentation of sugar III. dissolving sugar in water IV. Leaves changing color V. Melting of gold I, II, III I, III, V I, III, IV, V II
20)
Express 16.7 cubic feet in cubic centimeters.
16.7 ft3 x
 123 in3 13 ft3
x
 2.543 cm3 13 in3
= 472891 = 4.73 x 105 cm3 (with 3 sig figs)
 or with the cubes worked out:
16.7 ft3 x
 1728 in3 1 ft3
x
 16.387 cm3 1 in 3
21)
25.0 g of Liquid A has a volume of 16.8 mL. 100.0 dg of Liquid B has a volume of 12.7 cm3. Which substance is more dense?
Liquid A: D =
 25.0 g 16.8 mL
= 1.5 g/mL
Liquid B: 100 dg x
 1 g 10 dg
= 10 g D =
 10 g 12.7 mL
= 0.79 g/mL