Question 1

Which of the following best describes the bonding and electron arrangement in lithium nitride ($$\mathrm{Li_3N}$$)?

Accepted Answer

It is an ionic compound with lithium atoms donating electrons to nitrogen, resulting in a full octet for nitrogen.

Question 2

Which of the following molecules exhibits resonance, and how many resonance structures does it have?

Accepted Answer

Nitrate ion ($$\mathrm{NO_3$^-}$$); three resonance structures

Question 3

Given the Lewis structure of carbon tetrachloride ($$\mathrm{$$CCl_4$$}$$), how many lone pairs of electrons are present in the molecule?

Accepted Answer

12 lone pairs

Question 4

Which of the following correctly ranks the elements in order of increasing electronegativity?

Accepted Answer

$$\mathrm{Ba \u003c Sr \u003c Te \u003c Se \u003c Cl}$$

Question 5

A 500.0 mL flask of gas at 230. torr is brought to sea level where the pressure is 760. torr, with temperature held constant. What is the new volume of the gas?

Accepted Answer

$$151\ \mathrm{mL}$$

Question 6

Which of the following statements about intermolecular forces and boiling points is correct?

Accepted Answer

Substances with stronger intermolecular forces generally have higher boiling points.

Question 7

Which of the following molecules can form hydrogen bonds?

Accepted Answer

$$\mathrm{NH_3$}$$, $$\mathrm{CH_3OH}$$, $$\mathrm{H_2O}$$, and $$\mathrm{HF}$$

Question 8

A solution is prepared by dissolving 40.0 g of NaOH in enough water to make 750. mL of solution. What is the molarity of the solution? ($$\mathrm{NaOH}$$ molar mass = $$40.0\ \mathrm{g/mol})$$

Accepted Answer

$$1.33\ \mathrm{M}$$

Question 9

A 25.0 mL sample of $$0.105\ \mathrm{M}$$ HCl is titrated with $$31.5\ \mathrm{mL} of $$NaOH. What is the concentration of the NaOH?

Accepted Answer

$$0.0833\ \mathrm{M}$$

Question 10

Which of the following best describes a volatile liquid?

Accepted Answer

A liquid with high vapor pressure and low boiling point

Question 11

Which of the following is the correct pH for a solution with $$[\mathrm{H_3O^+}] = 1.76 	imes 10$$^{-5}$$\ \mathrm{M}$$?

Accepted Answer

$$4.75$$

Question 12

A sample of hydrogen gas is collected over water at a total pressure of $$635\ \mathrm{mm\ Hg}$$ and $$10.0^\circ\mathrm{C}. If $$the vapor pressure of water at $$10.0^\circ\mathrm{C} is$$ $$9.2\ \mathrm{mm\ Hg}$$, what is the partial pressure of hydrogen gas?

Accepted Answer

$$626\ \mathrm{mm\ Hg}$$

Question 13

Which of the following best describes the molecular geometry of $$\mathrm{BF_3$} ($$boron trifluoride)?

Accepted Answer

Trigonal planar

Question 14

Which of the following is a correct example of a polar covalent bond?

Accepted Answer

$$\mathrm{HCl}$$

Question 15

A 36.1 mL sample of oxygen gas contains $$0.529$$ mol of oxygen. If the volume is increased to $$50.5 mL at $$constant temperature and pressure, what is the final mass of the sample?

Accepted Answer

$$23.7\ \mathrm{g\ O_2$}$$

Question 16

Which of the following best describes the process of dynamic equilibrium in a closed system?

Accepted Answer

Two opposite processes occur at equal rates, resulting in no net change.

Question 17

Which of the following solutions has the highest concentration of hydroxide ions?

Accepted Answer

pH = 12.49

Question 18

Which of the following is the correct formula for calculating the pH of a solution given $$[\mathrm{H_3O^+}]$$?

Accepted Answer

$$\mathrm{pH} = -\log_{10} [\mathrm{H_3O^+}]$$

Question 19

Which of the following best describes the difference between Arrhenius and Brønsted-Lowry definitions of acids and bases?

Accepted Answer

Arrhenius acids produce $$\mathrm{H^+} in $$water, bases produce $$\mathrm{OH^-}$$; Brønsted-Lowry acids donate protons, bases accept protons.

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