$$\text{Density} = \frac{\text{mass}}{\text{volume}}$$

$$1.34 \times 10^3$\ \text{lb/ft}^3$$

$$1\ \text{lb} = 453.6\ \text{g}$$ and $$1\ \text{ft} = 30.48\ \text{cm}$$

Question 1

Which of the following best defines density?

Accepted Answer

The amount of mass per unit of volume.

Question 2

Which formula correctly represents density?

Accepted Answer

$$	ext{Density} = \frac{	ext{mass}}{	ext{volume}}$$

Question 3

For solids and liquids, which of the following is NOT a typical unit for density?

Accepted Answer

$$	ext{mol/L}$$

Question 4

If the density of a gas is measured, which units are most appropriate?

Accepted Answer

$$	ext{g/dm}^3$$

Question 5

A sample of metal has a density of $$2.14\ 	ext{g/cm}^3. $$What is its density in $$	ext{lb/ft}^3$$? (1 lb = 453.6 g, 1 ft = 30.48 cm)

Accepted Answer

$$1.34 	imes 10^3$\ 	ext{lb/ft}^3$$

Question 6

If a blood sample contains 0.80 ppm of lead (Pb), how many grams of Pb are present in 1,000,000 g of blood?

Accepted Answer

$$0.80\ 	ext{g}$$

Question 7

Given that the density of blood is $$1.060\ 	ext{kg/dm}^3$$, how many grams of blood are in $$400.0\ 	ext{mL}$$?

Accepted Answer

$$424\ 	ext{g}$$

Question 8

If the blood lead level is 0.80 ppm, how many grams of Pb are found in $$400.0\ 	ext{mL} of $$blood? (Density of blood = $$1.060\ 	ext{kg/dm}^3)$$

Accepted Answer

$$0.339\ 	ext{mg}$$

Question 9

Which of the following statements about ppm (parts per million) is correct?

Accepted Answer

1 ppm means 1 gram of solute per 1 million grams of solution.

Question 10

A patient’s blood sample has a lead concentration of 0.80 ppm. If the patient has $$0.620\ 	ext{L} of $$blood, how many grams of Pb are present?

Accepted Answer

$$0.496\ 	ext{mg}$$

Question 11

Which conversion factor would you use to convert density from $$	ext{g/cm}^3 to$$ $$	ext{lb/ft}^3$$?

Accepted Answer

$$1\ 	ext{lb} = 453.6\ 	ext{g}$$ and $$1\ 	ext{ft} = 30.48\ 	ext{cm}$$

Question 12

Which of the following is the correct step to find the mass of Pb in a given volume of blood at a known ppm concentration?

Accepted Answer

Multiply the volume of blood by its density, then multiply by the ppm value divided by $$10^6.$$

Question 13

If a sample has a density of $$1.060\ 	ext{kg/dm}^3$$, what is its density in $$	ext{g/mL}$$?

Accepted Answer

$$1.060\ 	ext{g/mL}$$

Question 14

Which of the following is NOT a correct way to express density?

Accepted Answer

$$	ext{cm/g}$$

Question 15

A student measures the mass of a liquid as $$250\ 	ext{g}$$ and its volume as $$200\ 	ext{mL}. $$What is the density of the liquid?

Accepted Answer

$$1.25\ 	ext{g/mL}$$

Question 16

Which of the following best describes the significance of density in a medical context?

Accepted Answer

Density helps determine the concentration of substances in blood, which is important for diagnosing conditions like lead poisoning.

Question 17

If a gas has a density of $$0.0012\ 	ext{g/cm}^3$$, what is its density in $$	ext{g/dm}^3$$?

Accepted Answer

$$1.2\ 	ext{g/dm}^3$$

Density Concepts and Calculations in GOB Chemistry

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