Q: A student mixes acetic acid ($$\ce{CH3COOH}) $$and sodium acetate ($$\ce{NaCH3COO}) in $$water. Which equation should they use to calculate the pH of the resulting buffer solution?

$\text{pH} = \text{p}K_a + \log\left(\frac{[\text{Base}]}{[\text{Acid}]}\

Question 1

A reaction is found to be first order in A and second order in B. Which of the following correctly represents the rate law for this reaction?

Accepted Answer

$$	ext{rate} = k[A][B]^2$$

Question 2

The decomposition of hydrogen peroxide ($$\ce{H2O2}) is $$catalyzed by iodide ions. Which statement best describes the effect of the catalyst on the reaction?

Accepted Answer

It decreases the activation energy ($$E_a) $$and increases the rate of reaction.

Question 3

For the reaction $$\ce{N2O4 (g)  2 NO2 (g)}$$, doubling the coefficients to $$\ce{2 N2O4 (g)  4 NO2 (g)}$$ will have what effect on the equilibrium constant ($$K_{eq}$$)?

Accepted Answer

$$K_{eq}$$ will be squared.

Question 4

A student mixes acetic acid ($$\ce{CH3COOH}) $$and sodium acetate ($$\ce{NaCH3COO}) in $$water. Which equation should they use to calculate the pH of the resulting buffer solution?

Accepted Answer

$	ext{pH} = 	ext{p}K_a + \log\left(\frac{[	ext{Base}]}{[	ext{Acid}]}\

Question 5

Which of the following best describes the collision model for chemical reactions?

Accepted Answer

Reactants must collide with sufficient energy and proper orientation to react.

Question 6

A solution is prepared by dissolving ammonium chloride ($$\ce{NH4Cl}) in $$water. Which statement is true about the acid-base properties of the resulting solution?

Accepted Answer

The solution will be acidic because $$\ce{NH4^+} is a $$weak acid.

Question 7

Which of the following is a correct expression for the solubility product constant ($$K_{sp}) $$for $$\ce{CaF2}$$?

Accepted Answer

$$K_{sp} = [\ce{Ca$$^{2+}$$}][\ce{F^-}]^2$$

Question 8

A reaction has a half-life that does not depend on the initial concentration. Which order is this reaction?

Accepted Answer

First order

Question 9

Which of the following statements about the effect of temperature on reaction rate is correct?

Accepted Answer

Increasing temperature increases the rate constant ($$k) by $$increasing the fraction of molecules with energy greater than $$E_a.$$

Question 10

A student is titrating a weak acid with a strong base. At the equivalence point, which statement is true?

Accepted Answer

The pH is greater than 7 because the conjugate base of the weak acid hydrolyzes.

Question 11

Which of the following is the correct relationship between $$K_a$$, $$K_b$$, and $$K_w$$ for a conjugate acid-base pair?

Accepted Answer

$$K_a 	imes K_b = K_w$$

Question 12

Which of the following best describes the common-ion effect?

Accepted Answer

The addition of an ion already present in solution decreases the solubility of a salt.

Question 13

Which of the following is a correct statement about Le Chatelier's Principle?

Accepted Answer

If the concentration of a reactant is increased, the equilibrium shifts toward the products.

Question 14

Which of the following is true for a buffer solution?

Accepted Answer

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

Question 15

Which of the following is the correct integrated rate law for a first-order reaction?

Accepted Answer

$$\ln([A]_t) = \ln([A]_0) - kt$$

Question 16

Which of the following is a Lewis acid?

Accepted Answer

$$\ce{BF3}$$ because it can accept an electron pair.

Question 17

A solution has $$[\ce{H^+}] = 1 	imes 10$$^{-5}$$ M. What is the pH of the solution?

Accepted Answer

pH = 5

Question 18

Which of the following best describes an amphiprotic substance?

Accepted Answer

It can act as both an acid and a base by donating or accepting a proton.

Question 19

A student mixes $$\ce{AgNO3}$$ and $$\ce{NaCl}$$ solutions. Which of the following will occur if $$[\ce{Ag^+}][\ce{Cl^-}] \u003e K_{sp}$$ for $$\ce{AgCl}$$?

Accepted Answer

A precipitate of $$\ce{AgCl}$$ will form.

General Chemistry Study Notes: Chemical Kinetics, Chemical Equilibrium, Acid-Base Equilibria, and Additional Aspects of Aqueous Equilibria

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