##### Mastering Chemistry Unit 1 - Conversions, density

Heaviest to lightest, spheres of equal volume:

Aluminum (2.70g/cm3)

Silver (10.49g/cm3)

Nickel (8.90g/cm3)

Silver, Nickel, Aluminum

Largest to smallest, cubes of equal mass:

Gold (19.32g/cm3)

Platinum (21.45g/cm3)

Lead (11.35g/cm3)

Lead, gold, platinum

A cube of osmium metal 1.500 cm on a side has a mass of 76.31 g at 25 ∘C.

What is its density in g/cm3 at this temperature?

22.61g/cm3

The density of titanium metal is 4.51 g/cm3 at 25 ∘C. What mass of titanium displaces 62.0 mL of water at 25 ∘C?

280g

The density of benzene at 15 ∘C is 0.8787 g/mL. Calculate the mass of 0.1700 L of benzene at this temperature.

149.4g

Two students determine the percentage of lead in a sample as a
laboratory exercise. The true percentage is 22.52%. The students'
results for three determinations are as follows:

**1. **22.52, 22.48, 22.54

Calculate the average percentage for the first set of data.

22.51

Two students determine the percentage of lead in a sample as a
laboratory exercise. The true percentage is 22.52%. The students'
results for three determinations are as follows:

**2. **22.64, 22.58, 22.62

Calculate the average percentage for the second set of data

22.61

Two students determine the percentage of lead in a sample as a
laboratory exercise. The true percentage is 22.52%. The students'
results for three determinations are as follows:

**1. **22.52, 22.48, 22.54

**2. **22.64, 22.58, 22.62

Tell which set is the more accurate based on the average.

a. First set is more accurate

b. Second set is more accurate

c. Two sets display the same accuracy

a. First set is more accurate

Two students determine the percentage of lead in a sample as a
laboratory exercise. The true percentage is 22.52%. The students'
results for three determinations are as follows:

**1. **22.52, 22.48, 22.54

Precision can be judged by examining the average of the deviations from the average value for that data set. Calculate the average value of the absolute deviations of each measurement from the average for the first set.

2×10^{−2}

Two students determine the percentage of lead in a sample as a laboratory exercise. The true percentage is 22.52%. The students' results for three determinations are as follows:

**2. **22.64, 22.58, 22.62

Calculate the average value of the absolute deviations of each measurement from the average for the second set.

2×10^{−2}

Two students determine the percentage of lead in a sample as a
laboratory exercise. The true percentage is 22.52%. The students'
results for three determinations are as follows:

**1. **22.52, 22.48, 22.54

**2. **22.64, 22.58, 22.62

Which set is more precise?

a. First set is more precise

b. Second set is more precise

c. Two sets display the same precision

c. Two sets display the same precision

The U.S. quarter has a mass of 5.67 g and is approximately 1.55 mm thick.

How many quarters would have to be stacked to reach 575 ft, the height of the Washington Monument?

1.13×10^{5} quarters

The U.S. quarter has a mass of 5.67 g and is approximately 1.55 mm thick.

How much would this stack weigh?

m = 6.41×10^{5} g

The U.S. quarter has a mass of 5.67 g and is approximately 1.55 mm thick.

How much money would this stack contain?

$2.83×10^{4}

The U.S. quarter has a mass of 5.67 g and is approximately 1.55 mm thick.

The US National Debt Clock showed the outstanding public debt to be $11,687,233,914,811.11 on August 19, 2009. How many stacks like the one described would be necessary to pay off this debt?

4.13×10^{8} stacks

Gold can be hammered into extremely thin sheets called gold leaf. An architect wants to cover a 100. ft×84.0 ft ceiling with gold leaf that is five-millionths of an inch thick. The density of gold is 19.32 g/cm3, and gold costs $ 953 per troy ounce (1 troy ounce = 31.1034768 g). How much will it cost the architect to buy the necessary gold?

$5.87×10^{4}