Question 1

A sample of an unknown gas has a mass of 2.80 g and occupies a volume of 1.12 L at 1.00 atm and 273 K. What is the molar mass of the gas? (Use $$PV = nRT$$, $$R = 0.0821\ \mathrm{L\cdot atm\cdot $$mol^{-1}$$\cdot K$$^{-1}$$})$$

Accepted Answer

$$56.0\ \mathrm{g\cdot $$mol^{-1}$$}$$

Question 2

Which of the following statements best explains why sodium chloride ($$\mathrm{NaCl}) $$conducts electricity when dissolved in water but not as a solid?

Accepted Answer

Ions are free to move in aqueous solution but fixed in the solid lattice.

Question 3

Which of the following elements has the highest first ionization energy?

Accepted Answer

Neon ($$\mathrm{Ne})$$

Question 4

A 25.0 mL sample of $$0.200\ \mathrm{M}$$ $$\mathrm{HCl} is $$titrated with $$0.100\ \mathrm{M}$$ $$\mathrm{NaOH}. $$What volume of $$\mathrm{NaOH} is $$required to reach the equivalence point?

Accepted Answer

$$50.0\ \mathrm{mL}$$

Question 5

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

Accepted Answer

Carbon dioxide ($$\mathrm{CO_2$})$$

Question 6

Which of the following best describes the process occurring when ice melts at $$0^\circ\mathrm{C}$$?

Accepted Answer

Hydrogen bonds between water molecules are partially broken.

Question 7

Which of the following sets of quantum numbers is NOT allowed for an electron in an atom?

Accepted Answer

$$n=2,\ l=2,\ m_l=0,\ m_s=+\frac{1}{2}$$

Question 8

Which of the following best explains why fluorine is more electronegative than chlorine?

Accepted Answer

Fluorine has a smaller atomic radius and a higher effective nuclear charge.

Question 9

A reaction has $$\Delta H = -125\ \mathrm{kJ}$$ and $$\Delta S = +50\ \mathrm{J\cdot K$$^{-1}$$}. At $$what temperature (in K) does the reaction change from spontaneous to nonspontaneous? (Use $$\Delta G = \Delta H - T\Delta S)$$

Accepted Answer

$$2500\ \mathrm{K}$$

Question 10

Which of the following best describes the hybridization of the central atom in methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

$$sp^3$$

Question 11

Which of the following is the correct net ionic equation for the reaction between aqueous solutions of $$\mathrm{Na_2SO_4}$$ and $$\mathrm{$$BaCl_2$$}$$?

Accepted Answer

$$\mathrm{Ba$$^{2+}$$ (aq) + SO_4$^{2-} (aq) \rightarrow $$BaSO_4$$ (s)}$$

Question 12

Which of the following best explains why water has a higher boiling point than methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

Water forms hydrogen bonds, which are stronger than the London dispersion forces in methane.

Question 13

Which of the following is the correct electron configuration for a ground-state calcium atom ($$\mathrm{Ca}$$, $$Z=20$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^6$$\ $$4s^2$$

Question 14

A sample of gas is collected over water at $$25^\circ\mathrm{C}$$ and a total pressure of $$755\ \mathrm{mmHg}. $$The vapor pressure of water at this temperature is $$24\ \mathrm{mmHg}. $$What is the partial pressure of the dry gas?

Accepted Answer

$$731\ \mathrm{mmHg}$$

Question 15

Which of the following best describes the trend in atomic radius across a period from left to right?

Accepted Answer

Atomic radius decreases due to increasing nuclear charge.

Question 16

Which of the following is the correct empirical formula for a compound containing 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 17

Which of the following best explains why the reaction $$\mathrm{2H_2O_2 (aq) \rightarrow 2H_2O (l) + O_2$ (g)} is $$classified as a disproportionation reaction?

Accepted Answer

Oxygen is both oxidized and reduced in the same reaction.

Question 18

Which of the following statements about the kinetic molecular theory of gases is correct?

Accepted Answer

Gas particles are in constant, random motion and collisions are perfectly elastic.

Question 19

A solution is prepared by dissolving $$10.0\ \mathrm{g} of $$glucose ($$\mathrm{C_6H_{12}O_6$}) in $$enough water to make $$250.0\ \mathrm{mL} of $$solution. What is the molarity of the solution? (Molar mass of glucose = $$180.0\ \mathrm{g\cdot $$mol^{-1}$$})$$

Accepted Answer

$$0.222\ \mathrm{M}$$

General Chemistry I: Core Concepts and Chapter Summaries

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