Question 1

Which of the following best describes the Law of Conservation of Mass as it applies to a chemical reaction in a closed system?

Accepted Answer

The total mass of the reactants is equal to the total mass of the products.

Question 2

A student mixes 25.0 g of sodium chloride with 100.0 g of water in a beaker. After the salt dissolves, what is the total mass of the solution?

Accepted Answer

$$125.0\ \mathrm{g}$$

Question 3

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 4

A sample of gas occupies $$2.0\ \mathrm{L} at$$ $$1.0\ \mathrm{atm}$$ and $$300\ \mathrm{K}. If $$the pressure is increased to $$2.0\ \mathrm{atm}$$ and the temperature is raised to $$600\ \mathrm{K}$$, what is the new volume of the gas? (Assume ideal gas behavior.)

Accepted Answer

$$4.0\ \mathrm{L}$$

Question 5

Which of the following best explains why water is a polar molecule?

Accepted Answer

Water has a bent molecular shape and an unequal distribution of electrons.

Question 6

Which of the following is the correct electron configuration for a neutral atom of sodium ($$Z=11$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^1$$

Question 7

A solution is prepared by dissolving $$10.0\ \mathrm{g} of $$NaOH in enough water to make $$500.0\ \mathrm{mL} of $$solution. What is the molarity of the solution? ($$M_{NaOH} = 40.0\ \mathrm{g/mol})$$

Accepted Answer

$$0.50\ \mathrm{M}$$

Question 8

Which of the following best describes a precipitation reaction?

Accepted Answer

A reaction in which two aqueous solutions combine to form an insoluble solid.

Question 9

Which of the following is the correct balanced equation for the reaction between hydrochloric acid and sodium hydroxide?

Accepted Answer

$$\mathrm{HCl} + \mathrm{NaOH} \rightarrow \mathrm{NaCl} + \mathrm{H_2O}$$

Question 10

A sample of calcium carbonate ($$\mathrm{$$CaCO_3$$}) is $$heated and decomposes according to the following reaction: $$\mathrm{$$CaCO_3$$} (s) \rightarrow \mathrm{CaO} (s) + \mathrm{CO_2$} (g). If$$ $$10.0\ \mathrm{g} of$$ $$\mathrm{$$CaCO_3$$} is $$decomposed, how many grams of $$\mathrm{CO_2$}$$ are produced? ($$M_{$$CaCO_3$$} = 100.0\ \mathrm{g/mol}$$, $$M_{CO_2$} = 44.0\ \mathrm{g/mol})$$

Accepted Answer

$$4.4\ \mathrm{g}$$

Question 11

Which of the following statements about acids and bases is correct according to the Brønsted-Lowry theory?

Accepted Answer

An acid is a proton donor and a base is a proton acceptor.

Question 12

A $$0.10\ \mathrm{M}$$ solution of hydrochloric acid ($$\mathrm{HCl}) $$has a pH closest to:

Accepted Answer

$$1.0$$

Question 13

Which of the following best describes chromatography as used in the laboratory?

Accepted Answer

A technique for separating mixtures based on differences in the movement of components through a stationary phase.

Question 14

Which of the following is the correct Lewis structure for carbon dioxide ($$\mathrm{CO_2$}$$)?

Accepted Answer

O=C=O, with each oxygen atom having two lone pairs.

Question 15

A student is given a mixture of sand and salt. Which of the following procedures would best separate the two substances?

Accepted Answer

Dissolve the mixture in water, filter to remove the sand, then evaporate the water to recover the salt.

Question 16

Which of the following best explains why noble gases are generally unreactive?

Accepted Answer

They have completely filled valence electron shells.

Question 17

A $$2.00\ \mathrm{L}$$ sample of gas at $$27^\circ\mathrm{C}$$ and $$1.00\ \mathrm{atm} is $$compressed to $$1.00\ \mathrm{L}$$ and heated to $$327^\circ\mathrm{C}. $$What is the final pressure of the gas? (Assume ideal gas behavior.)

Accepted Answer

$$6.0\ \mathrm{atm}$$

Question 18

Which of the following is a property of metals that distinguishes them from nonmetals?

Accepted Answer

Metals are good conductors of electricity.

Question 19

Which of the following best describes the process of titration in acid-base chemistry?

Accepted Answer

A technique in which a solution of known concentration is used to determine the concentration of an unknown solution.

Question 20

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

Accepted Answer

$$\mathrm{Density} = \frac{\mathrm{Mass}}{\mathrm{Volume}}$$

Introduction to Chemistry: Course Syllabus and Weekly Topics Overview

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