$$4.09 \times 10$$^{23}$$ atoms

$$1.75 \times 10$$^{24}$$ atoms

Question 1

Which of the following best describes an element?

Accepted Answer

A substance that contains only one type of atom.

Question 2

Which of the following is an example of a homogeneous mixture?

Accepted Answer

Air

Question 3

A sample of lead (Pb) has a mass of 22.7 g and a volume of 2.0 cm$$^3. $$What is its density?

Accepted Answer

$$11.35\ \mathrm{g/cm^3$}$$

Question 4

Which property is considered intensive?

Accepted Answer

Density

Question 5

Which process is used to separate a mixture based on differences in boiling points?

Accepted Answer

Distillation

Question 6

A 153 g rectangular solid has edge lengths 8.2 cm, 5.1 cm, and 4.7 cm. What is its density?

Accepted Answer

$$0.79\ \mathrm{g/cm^3$}$$

Question 7

Which of the following is a chemical property?

Accepted Answer

Reactivity with water

Question 8

Which statement about compounds is correct?

Accepted Answer

Compounds contain two or more different types of atoms chemically bonded.

Question 9

How many atoms are in 0.68 moles of zinc?

Accepted Answer

$$4.09 	imes 10$$^{23}$$ atoms

Question 10

Which of the following changes is endothermic?

Accepted Answer

Ice melting

Question 11

A sample of butane (C$$_4H$_{10}) $$contains 288 g carbon and 60 g hydrogen. What is the total mass of the sample?

Accepted Answer

$$348\ \mathrm{g}$$

Question 12

Which of the following is NOT a physical means of separating mixtures?

Accepted Answer

Electrolysis

Question 13

Which of the following best describes a molecule?

Accepted Answer

A neutral group of bonded atoms.

Question 14

What is the mass of 2.65 $$	imes 10$^{23}$$ atoms of neon? (Molar mass of Ne = 20.18 g/mol)

Accepted Answer

$$8.88\ \mathrm{g}$$

Question 15

Which statement about the Law of Conservation of Energy is correct?

Accepted Answer

Energy cannot be created or destroyed, only transformed.

Question 16

Which of the following is an example of an extensive property?

Accepted Answer

Mass

Question 17

How many moles are in 3.79 $$	imes 10$^{23}$$ atoms of zinc?

Accepted Answer

$$0.63$$ moles

Question 18

Which of the following is a heterogeneous mixture?

Accepted Answer

Salad

Question 19

A 119 g solid cylinder has a radius of 1.8 cm and height 1.5 cm. What is its density? (Volume of cylinder $$= \pi r^2$ h)$$

Accepted Answer

$$7.83\ \mathrm{g/cm^3$}$$

Question 20

How many atoms are in 421 g of promethium? (Molar mass of Pm = 145 g/mol)

Accepted Answer

$$1.75 	imes 10$$^{24}$$ atoms

Unit 2: Matter and Energy – Foundations of General Chemistry

Study Guide - Practice Questions