Question 1

Which of the following statements best describes an extensive property of a substance?

Accepted Answer

It depends on the amount of substance present.

Question 2

A student is asked to balance the following chemical equation: $$\mathrm{C_2H_6} + \mathrm{O_2$} \rightarrow \mathrm{CO_2$} + \mathrm{H_2O}. $$What is the correct set of coefficients (in order: $$\mathrm{C_2H_6}$$, $$\mathrm{O_2$}$$, $$\mathrm{CO_2$}$$, $$\mathrm{H_2O}$$)?

Accepted Answer

$$2, 7, 4, 6$$

Question 3

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

Accepted Answer

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

Question 4

A sample of gas occupies $$2.50\ \mathrm{L} at$$ $$1.00\ \mathrm{atm}$$ and $$300\ \mathrm{K}. $$What will be its volume at $$2.00\ \mathrm{atm}$$ and $$400\ \mathrm{K}$$? (Assume ideal gas behavior.)

Accepted Answer

$$1.67\ \mathrm{L}$$

Question 5

Which of the following is the correct electron configuration for a ground-state phosphorus atom ($$Z=15$$)?

Accepted Answer

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

Question 6

Which of the following statements about the first law of thermodynamics is correct?

Accepted Answer

The total energy of an isolated system is constant.

Question 7

Which of the following molecules is expected to have the largest dipole moment?

Accepted Answer

$$\mathrm{H_2O}$$

Question 8

A $$0.100\ \mathrm{mol}$$ sample of $$\mathrm{NaCl} is $$dissolved in enough water to make $$500\ \mathrm{mL} of $$solution. What is the molarity of the solution?

Accepted Answer

$$0.200\ \mathrm{M}$$

Question 9

Which of the following best describes the effect of increasing temperature on the solubility of most solid solutes in water?

Accepted Answer

Solubility increases as temperature increases.

Question 10

Which of the following is the correct expression for the ideal gas law?

Accepted Answer

$$PV = nRT$$

Question 11

Which of the following best explains why ionic compounds generally have higher melting points than covalent compounds?

Accepted Answer

Ionic bonds are stronger than most covalent bonds due to electrostatic attraction between ions.

Question 12

A reaction has $$\Delta H = -100\ \mathrm{kJ}$$ and $$\Delta S = -200\ \mathrm{J\ K$$^{-1}$$}. At $$what temperature (in K) does the reaction become non-spontaneous?

Accepted Answer

$$500\ \mathrm{K}$$

Question 13

Which of the following is the correct order of increasing atomic radius for the elements $$\mathrm{Na}$$, $$\mathrm{Mg}$$, and $$\mathrm{Al}$$?

Accepted Answer

$$\mathrm{Al} \u003c \mathrm{Mg} \u003c \mathrm{Na}$$

Question 14

Which of the following best describes the VSEPR geometry of $$\mathrm{NH_3$}$$?

Accepted Answer

Trigonal pyramidal

Question 15

Which of the following statements about the quantum numbers for electrons in atoms is correct?

Accepted Answer

The magnetic quantum number ($$m_l) $$determines the orientation of the orbital.

Question 16

Which of the following is the best explanation for the trend in ionization energy across a period in the periodic table?

Accepted Answer

Ionization energy increases due to increasing nuclear charge with little increase in shielding.

Question 17

A $$10.0\ \mathrm{g}$$ sample of ice at $$0^\circ\mathrm{C} is $$added to $$100.0\ \mathrm{g} of $$water at $$30.0^\circ\mathrm{C}. $$What is the final temperature of the mixture? ($$\Delta H_{fus}$$ for water $$= 334\ \mathrm{J/g}$$, $$c_{water} = 4.18\ \mathrm{J/g\ ^\circ C})$$

Accepted Answer

$$21.1^\circ\mathrm{C}$$

Question 18

Which of the following best describes the effect of a catalyst on a chemical reaction?

Accepted Answer

It lowers the activation energy, increasing the reaction rate.

Question 19

Which of the following is the correct Lewis structure for $$\mathrm{CO_2$}$$?

Accepted Answer

O=C=O, with each O atom having two lone pairs

Question 20

Which of the following best explains why $$\mathrm{Cl_2$} is a $$nonpolar molecule even though it contains polarizable electrons?

Accepted Answer

The molecule is composed of two identical atoms, so the electron distribution is symmetrical.

General Chemistry I: Core Topics and Study Guide

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