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

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

$1\ \text{lb} = 453.6\ \text{g}$ 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

Study Guide - Practice Questions