Question 1

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

Accepted Answer

A compound is composed of two or more elements chemically combined in fixed proportions, while a mixture is a physical combination of substances.

Question 2

A student mixes 50.0 mL of water at $$25.0\ ^\circ\mathrm{C}$$ with 50.0 mL of water at $$75.0\ ^\circ\mathrm{C}. $$Assuming no heat is lost to the surroundings, what is the final temperature of the mixture?

Accepted Answer

$$50.0\ ^\circ\mathrm{C}$$

Question 3

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

Accepted Answer

Rusting of an iron nail

Question 4

Which law states that in a chemical reaction, matter is neither created nor destroyed?

Accepted Answer

Law of Conservation of Mass

Question 5

A sample contains $$3.01 	imes 10$$^{23}$$ molecules of carbon dioxide. How many moles of carbon dioxide are present?

Accepted Answer

$$0.50$$ mol

Question 6

Which of the following best explains why helium is used to fill balloons instead of hydrogen?

Accepted Answer

Helium is non-flammable, making it safer than hydrogen.

Question 7

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 8

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group have the same number of valence electrons.

Question 9

A solution is prepared by dissolving $$5.00 g of $$NaCl in enough water to make $$250.0 mL of $$solution. What is the molarity of the solution? ($$\mathrm{NaCl}$$ molar mass = $$58.44 g/$$mol)

Accepted Answer

$$0.342 M$$

Question 10

Which of the following best describes the shape of a water molecule ($$\mathrm{H_2O}$$)?

Accepted Answer

Bent

Question 11

Which of the following is a correct statement about endothermic and exothermic reactions?

Accepted Answer

Endothermic reactions absorb heat from the surroundings.

Question 12

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number ($$l)$$

Question 13

Which of the following is the correct electron configuration for a neutral oxygen atom?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^4$$

Question 14

A gas occupies $$2.50 L at$$ $$1.00$$ atm and $$300 K. $$What volume will it occupy at $$2.00$$ atm and $$300 K$$? (Assume ideal gas behavior.)

Accepted Answer

$$1.25 L$$

Question 15

Which of the following best explains why salt (NaCl) dissolves in water?

Accepted Answer

The polar water molecules stabilize the separated Na$$^+$$ and Cl$$^-$$ ions.

Question 16

Which of the following is a correct statement about isotopes?

Accepted Answer

Isotopes of an element have different numbers of neutrons.

Question 17

Which of the following is the correct formula for calculating the energy change ($$\Delta E) in a $$system?

Accepted Answer

$$\Delta E = q + w$$

Question 18

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight electrons in their outer shell.

Question 19

Which of the following is a real-world application of stoichiometry?

Accepted Answer

Determining the amount of fertilizer needed for a specific crop yield.

Question 20

Which of the following best explains why ice floats on water?

Accepted Answer

Hydrogen bonding causes ice to have an open, hexagonal structure.

General Chemistry I: Course Overview and Study Strategies

Study Guide - Practice Questions

Study Guide - Flashcards