Question 1

Which of the following best describes an element?

Accepted Answer

A substance that cannot be broken down into simpler substances by chemical means.

Question 2

Which of the following is the correct electron configuration for a neutral atom of sodium ($$Z = 11$$)?

Accepted Answer

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

Question 3

A sample of gas occupies $$2.0\ \mathrm{L} at$$ $$1.0\ \mathrm{atm}$$ and $$300\ \mathrm{K}. If $$the pressure is increased to $$2.0\ \mathrm{atm}$$ and the temperature is raised to $$600\ \mathrm{K}$$, what is the new volume of the gas? (Assume ideal gas behavior.)

Accepted Answer

$$4.0\ \mathrm{L}$$

Question 4

Which of the following statements about ionic and covalent bonds is correct?

Accepted Answer

Ionic bonds involve the transfer of electrons, while covalent bonds involve the sharing of electrons.

Question 5

Which of the following compounds is most likely to be soluble in water?

Accepted Answer

$$\mathrm{NaCl}$$

Question 6

A solution is prepared by dissolving $$10.0\ \mathrm{g} of $$glucose ($$\mathrm{C_6H_{12}O_6$}$$, molar mass $$= 180\ \mathrm{g/mol}) in $$enough water to make $$500\ \mathrm{mL} of $$solution. What is the molarity of the solution?

Accepted Answer

$$0.111\ \mathrm{M}$$

Question 7

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

Accepted Answer

Ice is less dense than liquid water due to the hydrogen bonding that creates an open hexagonal structure.

Question 8

Which of the following is the correct balanced equation for the combustion of propane ($$\mathrm{C_3H_8}$$)?

Accepted Answer

$$\mathrm{C_3H_8} + 5\ \mathrm{O_2$} \rightarrow 3\ \mathrm{CO_2$} + 4\ \mathrm{H_2O}$$

Question 9

A patient receives an intravenous solution containing $$0.9\%$$ $$\mathrm{NaCl} ($$normal saline). What is the main reason this solution is used in medicine?

Accepted Answer

It is isotonic with human blood cells, preventing cell lysis or crenation.

Question 10

Which of the following is the correct net ionic equation for the reaction between aqueous solutions of $$\mathrm{$$AgNO_3$$}$$ and $$\mathrm{NaCl}$$?

Accepted Answer

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

Question 11

Which of the following is the correct expression for the equilibrium constant $$K_c$$ for the reaction $$aA + bB \rightleftharpoons cC + dD$$?

Accepted Answer

$$K_c = \dfrac{[C]^c [D]^d}{[A]^a [B]^b}$$

Question 12

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

Accepted Answer

$$12.5\ \mathrm{mL}$$

Question 13

Which of the following best describes the process of oxidation in a redox reaction?

Accepted Answer

Loss of electrons by a substance.

Question 14

Which of the following is a correct statement about catalysts?

Accepted Answer

Catalysts lower the activation energy of a reaction without being consumed.

Question 15

A radioactive isotope has a half-life of $$10$$ years. If you start with $$80\ \mathrm{g}$$, how much remains after $$30$$ years?

Accepted Answer

$$10\ \mathrm{g}$$

Question 16

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

Accepted Answer

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

Question 17

Which of the following best explains why increasing the temperature generally increases the rate of a chemical reaction?

Accepted Answer

It increases the kinetic energy of the molecules, leading to more frequent and energetic collisions.

Question 18

A buffer solution is prepared by mixing equal concentrations of acetic acid ($$\mathrm{CH_3COOH}) $$and sodium acetate ($$\mathrm{CH_3COONa}). $$What will happen to the pH if a small amount of strong acid is added?

Accepted Answer

The pH will decrease slightly, but the buffer will resist large changes.

Question 19

Which of the following is the correct formula for calculating the energy of a photon?

Accepted Answer

$$E = h 
u$$

Question 20

A $$0.50\ \mathrm{mol}$$ sample of an ideal gas is at $$300\ \mathrm{K}$$ and $$2.0\ \mathrm{atm}. $$What is the volume of the gas? ($$R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$})$$

Accepted Answer

$$6.15\ \mathrm{L}$$

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