Q: A solution contains 0.10 M $$\mathrm{Ca$$^{2+}$$}$$ and 0.10 M $$\mathrm{F^-}. $$Given $$K_{sp}$$ for $$\mathrm{$$CaF_2$$} is$$ $$3.9 \times 10$$^{-11}$$, will a precipitate form?

Yes, because $$Q = [Ca$$^{2+}$$][F^-]^2 = 1.0 \times 10$$^{-3}$$ \gg K_{sp}$$

Question 1

Which of the following statements best explains why the solubility of most solid salts increases with temperature?

Accepted Answer

Increasing temperature increases the kinetic energy of water molecules, allowing them to break ionic bonds more easily.

Question 2

A solution is prepared by dissolving 10.0 g of NaCl in 100.0 g of water. Which colligative property will be affected the most by the addition of NaCl?

Accepted Answer

Boiling point elevation

Question 3

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

Accepted Answer

It lowers the activation energy, increasing the rate of both the forward and reverse reactions.

Question 4

A reaction has a rate constant $$k$$ that doubles when the temperature increases from $$25^\circ C to$$ $$35^\circ C. $$Which equation would you use to determine the activation energy $$E_a$$?

Accepted Answer

$$\ln \left( \frac{k_2$}{k_1$} \right) = -\frac{E_a}{R} \left( \frac{1}{T_2$} - \frac{1}{T_1$} \right)$$

Question 5

Which of the following is the correct net ionic equation for the precipitation of silver chloride when solutions of AgNO$$_3$$ and NaCl are mixed?

Accepted Answer

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

Question 6

A buffer solution is made by mixing equal moles of acetic acid ($$\mathrm{CH_3COOH}) $$and sodium acetate ($$\mathrm{CH_3COONa}). $$Which equation would you use to calculate the pH of this buffer?

Accepted Answer

$$\mathrm{pH = p}K_a + \log \left( \frac{[A^-]}{[HA]} \right)$$

Question 7

Which of the following changes will shift the equilibrium of the reaction $$\mathrm{N_2$ (g) + 3H_2 (g) \rightleftharpoons 2NH_3 (g)} to $$the right, according to Le Chatelier's Principle?

Accepted Answer

Increasing the pressure by decreasing the volume

Question 8

A 0.10 M solution of a weak acid ($$\mathrm{HA}) $$has a pH of 3.0. What is the acid dissociation constant $$K_a$$ for this acid?

Accepted Answer

$$K_a = 1.0 	imes 10$$^{-5}$$

Question 9

Which of the following best describes the function of a salt bridge in a galvanic (voltaic) cell?

Accepted Answer

It maintains electrical neutrality by allowing the flow of ions between the half-cells.

Question 10

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

Accepted Answer

10 g

Question 11

Which of the following is the correct expression for the equilibrium constant $$K_c$$ for the reaction $$\mathrm{2SO_2 (g) + O_2$ (g) \rightleftharpoons 2SO_3 (g)}$$?

Accepted Answer

$$K_c = \frac{[SO_3$]^2}{[SO_2$]^2[O_2$]}$$

Question 12

Which of the following statements about entropy ($$\Delta S) is $$correct?

Accepted Answer

The entropy of the universe increases for all spontaneous processes.

Question 13

A solution contains 0.10 M $$\mathrm{Ca$$^{2+}$$}$$ and 0.10 M $$\mathrm{F^-}. $$Given $$K_{sp}$$ for $$\mathrm{$$CaF_2$$} is$$ $$3.9 	imes 10$$^{-11}$$, will a precipitate form?

Accepted Answer

Yes, because $$Q = [Ca$$^{2+}$$][F^-]^2 = 1.0 	imes 10$$^{-3}$$ \gg K_{sp}$$

Question 14

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

Accepted Answer

The hydrogen bonding in ice creates an open lattice structure, making it less dense than liquid water.

Question 15

Which of the following is the correct Nernst equation for a cell at non-standard conditions?

Accepted Answer

$$E = E^\circ - \frac{0.0592}{n} \log Q$$

Question 16

Which of the following is a correct statement about the Arrhenius equation?

Accepted Answer

It shows that the rate constant $$k$$ increases exponentially with increasing temperature.

Question 17

Which of the following best describes the function of a buffer in blood?

Accepted Answer

It resists changes in pH when small amounts of acid or base are added.

Question 18

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

Accepted Answer

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

Question 19

Which of the following statements about nuclear fission and fusion is correct?

Accepted Answer

Nuclear fusion combines light nuclei to form heavier nuclei, releasing energy.

General Chemistry I & II: Course Syllabus and Topic Overview

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