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 organized by increasing atomic number.

Question 3

A student measures the mass of a metal block as $$45.2\ \mathrm{g}$$ and its volume as $$12.1\ \mathrm{cm}^3. $$What is the density of the metal block, reported with the correct number of significant figures?

Accepted Answer

$$3.74\ \mathrm{g/cm}^3$$

Question 4

Which of the following is an example of an ionic bond?

Accepted Answer

The bond between sodium and chlorine in $$\mathrm{NaCl}$$

Question 5

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

Accepted Answer

Mole

Question 6

A sample of gas occupies a volume of $$2.50\ \mathrm{L}$$ and has a mass of $$5.00\ \mathrm{g}. $$What is the density of the gas?

Accepted Answer

$$0.50\ \mathrm{g/L}$$

Question 7

Which of the following best explains why water ($$\mathrm{H}_2\mathrm{O}) is $$classified as a compound?

Accepted Answer

It can be separated into hydrogen and oxygen by chemical means.

Question 8

Which of the following is NOT a property of matter?

Accepted Answer

It can be seen with the naked eye.

Question 9

A chemist records a measurement as $$0.04050\ \mathrm{kg}. $$How many significant figures does this measurement have?

Accepted Answer

4

Question 10

Which of the following best describes the location of electrons in an atom?

Accepted Answer

Electrons orbit the nucleus.

Question 11

Which of the following is a correct statement about covalent bonds?

Accepted Answer

Covalent bonds form when atoms share electron pairs.

Question 12

A student mixes two clear solutions and observes the formation of a white solid. Which of the following best explains this observation?

Accepted Answer

A chemical reaction has produced a compound.

Question 13

Which of the following is the correct formula for calculating density?

Accepted Answer

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

Question 14

Which of the following is an example of a pure substance?

Accepted Answer

Carbon dioxide ($$\mathrm{CO}_2)$$

Question 15

A hospital stores oxygen gas in a tank with a mass of $$16.0\ \mathrm{kg}$$ and a volume of $$12.0\ \mathrm{L}. $$What is the density of the oxygen gas in $$\mathrm{kg/L}$$?

Accepted Answer

$$1.33\ \mathrm{kg/L}$$

Question 16

Which of the following is the correct SI unit for temperature?

Accepted Answer

Kelvin

Question 17

Which of the following best describes an element?

Accepted Answer

A substance that cannot be broken down by chemical means.

Question 18

Which of the following is a correct statement about significant figures?

Accepted Answer

They express the precision of a measurement.

Question 19

A scientist needs to measure the length of a laboratory bench. Which SI unit should be used?

Accepted Answer

Meter

Question 20

Which of the following best explains why sodium chloride ($$\mathrm{NaCl}) is $$classified as a compound and not a mixture?

Accepted Answer

It has a fixed composition and unique properties.

Matter, Measurements, and Basic Chemical Concepts

Guida di studio - Domande di pratica

Study guide - Flashcard