Question 1

Which of the following statements about significant figures is correct when multiplying 2.34 (3 sig figs) by 0.00456 (3 sig figs)?

Accepted Answer

The answer should be rounded to 3 significant figures.

Question 2

Which of the following best describes the difference between atomic mass and mass number?

Accepted Answer

Atomic mass is the weighted average of all isotopes, while mass number is the sum of protons and neutrons.

Question 3

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number $$l$$

Question 4

Which electron configuration represents a chloride ion ($$\mathrm{Cl^-}$$)?

Accepted Answer

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

Question 5

Which of the following molecules is nonpolar, despite having polar bonds?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 6

Which of the following best explains why water ($$\mathrm{H_2O}) $$has a bent molecular shape?

Accepted Answer

The oxygen atom forms two bonds and has two lone pairs, causing electron pair repulsion.

Question 7

Which of the following is the correct Lewis structure for methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

A central carbon atom with four single bonds to four hydrogen atoms and no lone pairs on carbon.

Question 8

Which of the following statements about hybridization is correct for the carbon atom in ethene ($$\mathrm{C_2H_4}$$)?

Accepted Answer

Each carbon atom is $$sp^2$$ hybridized.

Question 9

A reaction has a theoretical yield of 10.0 g and an actual yield of 7.5 g. What is the percent yield?

Accepted Answer

$$75\%$$

Question 10

Which of the following best describes a limiting reactant in a chemical reaction?

Accepted Answer

The reactant that determines the amount of product formed.

Question 11

Which of the following is a correct net ionic equation for the reaction between aqueous solutions of sodium chloride and silver nitrate?

Accepted Answer

$$\mathrm{Ag^+ (aq) + Cl^- (aq) \rightarrow AgCl (s)}$$

Question 12

Which of the following best describes an exothermic reaction?

Accepted Answer

A reaction that releases heat to the surroundings.

Question 13

Which of the following equations correctly represents the first law of thermodynamics?

Accepted Answer

$$\Delta E = q + w$$

Question 14

A sample of gas occupies 5.0 L at 1.0 atm and 300 K. What volume will it occupy at 2.0 atm and 300 K?

Accepted Answer

2.5 L

Question 15

Which of the following gases will effuse the fastest under the same conditions?

Accepted Answer

$$\mathrm{H_2$}$$

Question 16

Which of the following best explains why the density of a gas increases when it is compressed at constant temperature?

Accepted Answer

The volume decreases while the mass remains constant.

Question 17

Which of the following is true about the enthalpy of formation ($$\Delta H_f^\circ) of an $$element in its standard state?

Accepted Answer

It is zero.

Question 18

Which of the following best describes the process of hybridization in the context of valence bond theory?

Accepted Answer

Mixing atomic orbitals to form new, equivalent hybrid orbitals.

Question 19

Which of the following is the correct formula for calculating the heat absorbed or released by a substance?

Accepted Answer

$$q = m c \Delta T$$

Question 20

A solution is prepared by dissolving 5.0 g of NaCl in enough water to make 250 mL of solution. What is the molarity of the solution? ($$\mathrm{NaCl}$$ molar mass = 58.44 g/mol)

Accepted Answer

0.342 M

General Chemistry I Final Exam Study Guide: Key Concepts and Principles

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