$$0.250\ \mathrm{L} \times \frac{1000\ \mathrm{mL}}{1\ \mathrm{L}} \times 1.05\ \mathrm{g/mL} = 262.5\ \mathrm{g}$$

Question 1

Which of the following best describes a compound?

Accepted Answer

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

Question 2

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements are arranged by increasing atomic number.

Question 3

A sample of a metal has a mass of 45.0 g and a volume of 15.0 mL. What is its density?

Accepted Answer

$$d = \frac{45.0\ \mathrm{g}}{15.0\ \mathrm{mL}} = 3.0\ \mathrm{g/mL}$$

Question 4

Which of the following is an example of a physical property?

Accepted Answer

Melting point

Question 5

A student measures the mass of a sample as 12.30 g and the volume as 4.0 mL. How many significant figures should the calculated density have?

Accepted Answer

2

Question 6

Which of the following best describes an ionic bond?

Accepted Answer

A bond formed by transferring electrons from a metal to a nonmetal.

Question 7

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

Accepted Answer

Mole

Question 8

A chemist finds a clear, colorless liquid in a laboratory. Which test would best determine if it is a pure substance or a mixture?

Accepted Answer

Measure its boiling point and compare it to the known boiling point of water.

Question 9

Which of the following statements about atoms is correct?

Accepted Answer

Protons and neutrons are found in the nucleus.

Question 10

A student records the following measurements: 2.50 m, 2.5 m, and 2.500 m. Which statement about significant figures is correct?

Accepted Answer

2.50 m has three significant figures.

Question 11

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

Accepted Answer

Water (H$$_2O)$$

Question 12

A patient is given 0.250 L of a saline solution. If the density of the solution is 1.05 g/mL, what is the mass of the solution in grams?

Accepted Answer

$$0.250\ \mathrm{L} 	imes \frac{1000\ \mathrm{mL}}{1\ \mathrm{L}} 	imes 1.05\ \mathrm{g/mL} = 262.5\ \mathrm{g}$$

Question 13

Which of the following best explains why ice floats on water?

Accepted Answer

Ice has a lower density than liquid water.

Question 14

Which of the following is NOT an SI base unit?

Accepted Answer

Gram

Question 15

A student dissolves table salt (NaCl) in water. Which type of matter is the resulting solution?

Accepted Answer

Mixture

Question 16

Which of the following best describes the difference between a solid and a gas?

Accepted Answer

A solid has a definite shape and volume, while a gas has neither.

Question 17

Which of the following is a correct application of the law of conservation of mass in a chemical reaction?

Accepted Answer

The total mass of reactants equals the total mass of products.

Question 18

A sample of carbon dioxide (CO$$_2) $$gas is compressed from 2.0 L to 1.0 L at constant temperature. What happens to the density of the gas?

Accepted Answer

The density doubles.

Question 19

Which of the following best describes the composition of an atom?

Accepted Answer

Protons and neutrons in the nucleus, electrons orbiting.

Question 20

A chemist needs to prepare 250.0 mL of a solution with a density of 1.20 g/mL. What mass of solute and solvent combined is required?

Accepted Answer

$$250.0\ \mathrm{mL} 	imes 1.20\ \mathrm{g/mL} = 300.0\ \mathrm{g}$$

Matter, Measurements, and Basic Atomic Structure

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