Question 1

Which of the following best describes the scientific method as it is applied in chemistry?

Accepted Answer

A systematic approach involving observation, hypothesis formation, experimentation, and analysis to understand natural phenomena.

Question 2

A student is asked to determine the density of an unknown liquid. She measures the mass as $$45.0\ \mathrm{g}$$ and the volume as $$36.0\ \mathrm{mL}. $$What is the density of the liquid, and which of the following best describes the correct calculation?

Accepted Answer

Density $$= \dfrac{45.0\ \mathrm{g}}{36.0\ \mathrm{mL}} = 1.25\ \mathrm{g/mL}$$

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

Which of the following best explains why water ($$\mathrm{H_2O}) is a $$polar molecule?

Accepted Answer

Water has a bent molecular geometry and a difference in electronegativity between hydrogen and oxygen.

Question 5

A balloon filled with helium gas has a volume of $$2.00\ \mathrm{L} at a $$pressure of $$1.00\ \mathrm{atm}. If $$the pressure is increased to $$2.00\ \mathrm{atm} at $$constant temperature, what will the new volume be? (Assume ideal gas behavior.)

Accepted Answer

$$1.00\ \mathrm{L}$$

Question 6

Which of the following is an example of a chemical change?

Accepted Answer

A piece of iron rusting when left outside.

Question 7

Which of the following best describes the difference between ionic and covalent bonds?

Accepted Answer

Ionic bonds involve the transfer of electrons from one atom to another, while covalent bonds involve the sharing of electrons.

Question 8

A sample contains $$0.50\ \mathrm{mol} of$$ $$\mathrm{NaCl}. $$What is the mass of this sample? (Molar mass of $$\mathrm{NaCl} = 58.44\ \mathrm{g/mol})$$

Accepted Answer

$$29.22\ \mathrm{g}$$

Question 9

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

Accepted Answer

They have a complete valence electron shell, making them stable.

Question 10

Which of the following is the correct balanced equation for the combustion of methane ($$\mathrm{CH_4$}) in $$oxygen?

Accepted Answer

$$\mathrm{CH_4$} + 2\ \mathrm{O_2$} \rightarrow \mathrm{CO_2$} + 2\ \mathrm{H_2O}$$

Question 11

A solution is prepared by dissolving $$10.0\ \mathrm{g} of $$glucose ($$\mathrm{C_6H_{12}O_6$}$$, molar mass $$= 180.16\ \mathrm{g/mol}) in $$enough water to make $$0.250\ \mathrm{L} of $$solution. What is the molarity of the solution?

Accepted Answer

$$0.222\ \mathrm{M}$$

Question 12

Which of the following best describes the process of radioactive decay?

Accepted Answer

An unstable nucleus emits particles or energy to become more stable.

Question 13

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

Accepted Answer

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

Question 14

A chemical reaction is at equilibrium when:

Accepted Answer

The rates of the forward and reverse reactions are equal.

Question 15

Which of the following best explains why salt is spread on icy roads in winter?

Accepted Answer

Salt lowers the freezing point of water, causing ice to melt at lower temperatures.

Question 16

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 17

Which of the following best describes the trend in atomic radius across a period in the periodic table?

Accepted Answer

Atomic radius decreases from left to right across a period.

Question 18

A patient receives $$500.0\ \mathrm{mL} of a $$saline solution containing $$0.90\ \mathrm{g} of$$ $$\mathrm{NaCl}$$ per $$100\ \mathrm{mL}. $$How many grams of $$\mathrm{NaCl}$$ does the patient receive?

Accepted Answer

$$4.50\ \mathrm{g}$$

Question 19

Which of the following best explains why carbon forms four covalent bonds in most of its compounds?

Accepted Answer

Carbon has four valence electrons and needs four more to complete its octet.

CHEM 101: Introduction to Chemistry – Syllabus and Course Structure Study Guide

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