Q: A student measures the mass of a sample as 12.345 g and its volume as 4.2 mL. What is the density of the sample, expressed with the correct number of significant figures?

$$d = \frac{12.345\ \text{g}}{4.2\ \text{mL}} = 2.9\ \text{g/mL}$$

Q: A sample of liquid mercury has a mass of 135 g and occupies a volume of 10.0 mL. What is its density?

$$d = \frac{135\ \text{g}}{10.0\ \text{mL}} = 13.5\ \text{g/mL}$$

Q: Which of the following is an example of a covalent bond?

The bond between hydrogen and oxygen in water ($$\text{H}_2\text{O})$$

Q: A patient receives a dose of medication that is 0.250 g. If the medication is dissolved in 5.00 mL of solution, what is the concentration in g/mL, using the correct number of significant figures?

$$\frac{0.250\ \text{g}}{5.00\ \text{mL}} = 0.0500\ \text{g/mL}$$

Question 1

Which of the following statements best describes a compound?

Accepted Answer

A substance composed of two or more elements chemically combined in a fixed ratio.

Question 2

Which SI unit would you use to measure the amount of a substance in a chemical reaction?

Accepted Answer

Mole

Question 3

A student measures the mass of a sample as 12.345 g and its volume as 4.2 mL. What is the density of the sample, expressed with the correct number of significant figures?

Accepted Answer

$$d = \frac{12.345\ 	ext{g}}{4.2\ 	ext{mL}} = 2.9\ 	ext{g/mL}$$

Question 4

Which of the following best explains why ionic bonds form between metals and nonmetals?

Accepted Answer

Metals lose electrons to nonmetals, resulting in oppositely charged ions that attract each other.

Question 5

Which of the following is NOT a pure substance?

Accepted Answer

Air

Question 6

A chemist needs to measure the temperature of a reaction. Which SI unit should they use?

Accepted Answer

Kelvin

Question 7

Which statement about the periodic table is correct?

Accepted Answer

Elements are arranged by increasing atomic number.

Question 8

Which of the following best describes the location of protons, neutrons, and electrons in an atom?

Accepted Answer

Protons and neutrons are in the nucleus; electrons orbit the nucleus.

Question 9

A sample of liquid mercury has a mass of 135 g and occupies a volume of 10.0 mL. What is its density?

Accepted Answer

$$d = \frac{135\ 	ext{g}}{10.0\ 	ext{mL}} = 13.5\ 	ext{g/mL}$$

Question 10

Which of the following is an example of a covalent bond?

Accepted Answer

The bond between hydrogen and oxygen in water ($$	ext{H}_2	ext{O})$$

Question 11

Which measurement contains the greatest number of significant figures?

Accepted Answer

12.345

Question 12

A student mixes two clear liquids and observes the formation of a white solid. Which best describes the white solid?

Accepted Answer

A precipitate formed by a chemical reaction.

Question 13

Which of the following is a real-world example of a chemical compound?

Accepted Answer

Table salt ($$	ext{NaCl})$$

Question 14

Which of the following statements about significant figures is correct?

Accepted Answer

Significant figures express the precision of a measurement.

Question 15

A patient receives a dose of medication that is 0.250 g. If the medication is dissolved in 5.00 mL of solution, what is the concentration in g/mL, using the correct number of significant figures?

Accepted Answer

$$\frac{0.250\ 	ext{g}}{5.00\ 	ext{mL}} = 0.0500\ 	ext{g/mL}$$

Question 16

Which of the following is NOT an SI unit?

Accepted Answer

Gram

Question 17

Which scenario best illustrates the difference between a physical and a chemical change?

Accepted Answer

Burning wood to form ash and gases is a chemical change.

Question 18

Which of the following best describes the relationship between mass, volume, and density?

Accepted Answer

$$d = \frac{m}{V}$$

Question 19

Which of the following is an element?

Accepted Answer

Oxygen ($$	ext{O}_2)$$

Question 20

A student is asked to identify a sample as a solid, liquid, or gas. Which property would best help them distinguish between these states of matter?

Accepted Answer

The sample's ability to change shape and volume

General Chemistry: Matter, Measurement, and Atomic Structure

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