Chapter 2 Review
Significant figures
How many significant figures in the following – if there are an infinite number of significant figures due to the fact the quantity is not a measurement, place an X in the space provided.
3.03 x 104 cm ______0.04210 cg ______9.00 x 10-34 Kg ______
0.00324 Km ______14 eggs ______20 kids ______
4032 g ______4.33 miles ______9110 mm ______
Perform the following calculations to the correct number of significant figures. Report your answer first as the calculator value, and then re-write the answer to the correct number of significant figures. Make certain to include the correct units.
V = 12.02 cm x 10 cm x 6.25 cm = ______= ______
V = 4/3 π (15.3 in)3 = ______= ______
P = 12.02 in + 0.4 in. + 8.022 in + 9 in = ______= ______
%error = |8.95 g/mL – 8.6 g/mL | / 8.95 g/mL x 100 = ______= ______
A = 45.0 cm x 180 cm = ______= ______
C = 2πr = 2 π (5.4 cm) = ______= ______
R = C / 2π = 43.0 cm / 2π = ______= ______
145 pennies – 35 pennies – 5 pennies = ______= ______
V = πr2h = π (3 in)2 (8.25 in) = ______= ______
Standard/Scientific Notation
1.43 x 10 -2 = ______7012 = ______
6.02 x 103 = ______0.4354 = ______
7.43 x 100 = ______7.956 = ______
Density
1. An object with a mass of 7.5 g raises the level of water in a graduated cylinder from 25.1 mL to 30.1 mL. What is the density of the object?
2. The density of aluminum is 2.7 g/cm3. How much water is displaced when dropping a 6.45 lb piece of aluminum into water?
3. A cube of gold-colored metal with a volume of 64 cm3 has a mass of 980 g. The density of pure gold is 19.3 g/cm3. Is the metal pure gold?
4. A rectangle is 6 in long, 3.5 cm wide, and 45 mm high. The rectangle has a density of 2.2 g/cm3. How heavy is the rectangle?
5. A chemist needs a volume equivalent to 25.0 grams of bromine for her experiment. What volume should she use? (The density of bromine is 3.12 g/mL.)
6. A 2.00 mL sample of substance A has a density of 18.4 g/mL and a 5.00 mL sample of substance B has a density of 35.5 g/mL. Do you have an equal mass of substances A and B?
7. Your teacher asks you to verify the density of a piece of copper metal. You determine the mass of the metal to be 68.684 grams. You then drop the piece of metal into a graduated cylinder filled with water to determine its volume by water displacement. But…WAIT A MINUTE, you forgot to record the initial volume of water in the graduated cylinder! You record the final volume of water in the cylinder as 83.2 mL. The density of copper is 8.92 g/cm3. What volume of water did you initially have in the graduated cylinder?
8. Equal amounts of mercury (density = 13.6 g/mL), ethanol (density = 0.785 g/mL), and water (density = 1.0 g/mL) are added to a beaker.
a. Describe the arrangement of the layers of liquid in the beaker.
b. A small cube (density = 1.59 g/cm3) is added to the beaker. Where will it be located among the layers of liquid?
Metric Conversions
Make the following conversions to the correct number of significant figures.
1.2 Tm = ______Km 45 usec = ______msec
0.034 dag = ______dg 8.965 hg = ______ug
176 mL = ______uL 456 pm = ______mm
90.5 nm = ______pm 5.34 GHz = ______MHz
5.06 Mm = ______m 4.8 L = ______cL
Which quantity is larger? (circle the larger quantity)
1.2 GHz or 120 MHz .56 ml or 56 ul
2.34 dag or 2340 g 76.8 pm or 7.68 nm
17.5 Tm or 17,500 Km 90.9 Kg or 9.09 Mg
Factor-Label
You and some friends are on a European vacation. There are 12 of you and your average weights are 192 lbs. It is a small elevator with a maximum weight capacity of 850 kg. How many of you can fit on the elevator at the same time? (Don’t worry about significant figures) Give the answer as a whole number of people, not as a decimal! Do not round up, as this exceeds the weight capacity.
The average attendance at a Hempfield Area football game is 6000. If 44 % of the fans eat an average of 1.5 Chic filet sandwiches, how many sandwiches should the Hempfield football parents have on hand? (Don’t worry about significant figures)
a) If the average profit from the sale of one of the sandwiches is .48 cents, how much profit is made
from the selling of the Chic filet sandwiches?
A 2.21 oz piece of gold nugget is found. If the density of gold is 19.22 g/cm3 and the gold nugget is spherical in shape, what is the approximate radius of that nugget? (Report your answer using the correct number of significant figures!)
The process of converting tree pulp into paper at a local mill is 85% efficient at converting the tree pulp into paper. How many pounds of tree pulp is needed to produce 1250 boxes of paper, with each box containing 12 reams of paper, with each ream containing 500 sheets of paper. The average weight of each ream is 2.85 Kg.
A sociologist discovers a strange society which has only women, no men of any kind. (Don't ask how they reproduce--that's biology.)
In this place, every household is composed of:
· 1 mother
· 2 young daughters
· 3 aunts (without children of their own)
· 3 cats
· 1 dog
The sociologist learns a few important facts about the society:
· Each adult female drives her own car.
· Each cat eats 1 can of food a day but the dogs need two cans per day.
· The daughters all have three different pairs of jeans and 7 tops that they wear.
· Each daughter also goes to school and brings with her 2 notebooks and 5 pens.
· Each household lives in a house (surprise, surprise) that is covered by a single roof.
· Each house has 13 rooms including the 3 bathrooms.
Now, here are the questions.
· How many girl's jeans would you find if you looked in enough homes to see 91 rooms?
· How many pets would follow you home after such a trip? (Assume that all possible pets do follow you.)
· If one aunt from each household on a street that has 42 bathrooms goes shopping for a week's worth of pet food, how many cans of dog food will be purchased. How many cans of cat food?
· If you stop at the mall and see 144 cars in the lot how many daughters are in the mall? (assume that all of the families went together in as many cars as they had available.)
· The CEO of a computer software company wants to hold a picnic in the local park. The park only allows 1355 pets at a time (it's a big park!), but it counts each dog twice since they make more of a mess. The park also only has space for 1360 cars (remember that each family always takes as many cars as possible). How many employee's families can she invite? What is the limiting factor in the invitation? (HINT:You have to do this one twice and compare answers!!)