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 $$12.0\ \mathrm{cm}^3. $$What is the density of the block, and how many significant figures should the answer have?

Accepted Answer

$$3.77\ \mathrm{g/cm}^3$$ with 3 significant figures

Question 4

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

Accepted Answer

The bond 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 $$2.50\ \mathrm{L}$$ and has a mass of $$5.00\ \mathrm{g}. $$What is its density?

Accepted Answer

$$0.200\ \mathrm{g/L}$$

Question 7

Which of the following statements about atoms is correct?

Accepted Answer

Protons and neutrons are found in the nucleus.

Question 8

Which of the following is a pure substance?

Accepted Answer

Carbon dioxide ($$\mathrm{CO_2$})$$

Question 9

A thermometer reads $$25.0\ ^\circ\mathrm{C}$$, but the actual temperature is $$25.00\ ^\circ\mathrm{C}. $$How many significant figures are in the measured value?

Accepted Answer

3

Question 10

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electron pairs between atoms.

Question 11

A chemist 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 new compound.

Question 12

Which of the following is NOT an SI base unit?

Accepted Answer

Gram

Question 13

A student records the following measurements: $$12.0\ \mathrm{cm}$$, $$12.00\ \mathrm{cm}$$, and $$12\ \mathrm{cm}. $$Which measurement has the greatest number of significant figures?

Accepted Answer

$$12.00\ \mathrm{cm}$$

Question 14

Which of the following is a correct statement about elements?

Accepted Answer

Elements are pure substances that cannot be broken down by chemical means.

Question 15

A block of aluminum has a mass of $$54.0\ \mathrm{g}$$ and a density of $$2.70\ \mathrm{g/cm}^3. $$What is its volume?

Accepted Answer

$$20.0\ \mathrm{cm}^3$$

Question 16

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

Accepted Answer

Water ($$\mathrm{H_2O})$$

Question 17

Which of the following best explains why density is considered an intensive property?

Accepted Answer

Density is the ratio of mass to volume, independent of sample size.

Question 18

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

Accepted Answer

$$d = m / V$$

Question 19

A student is asked to identify the state of matter for a sample that has a definite volume but no definite shape. Which state is it?

Accepted Answer

Liquid

Question 20

Which of the following best describes the difference between a mixture and a pure substance?

Accepted Answer

A mixture consists of two or more substances physically combined, while a pure substance has a fixed composition.

General Chemistry: Matter, Measurement, and Atomic Structure

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