Question 1

A student is investigating the effect of temperature on the rate of a chemical reaction. According to the Arrhenius equation, which of the following best explains why increasing temperature generally increases the reaction rate?

Accepted Answer

Increasing temperature increases the frequency of collisions and the fraction of molecules with energy greater than the activation energy.

Question 2

Which of the following best describes the difference between a strong acid and a weak acid in aqueous solution?

Accepted Answer

A strong acid completely ionizes in water, while a weak acid only partially ionizes.

Question 3

During a titration of a weak acid with a strong base, which of the following is true at the half-equivalence point?

Accepted Answer

The concentration of acid equals the concentration of its conjugate base, and $$\mathrm{pH} = \mathrm{p}K_a.$$

Question 4

A student measures the rate of disappearance of a reactant in a reaction and finds that doubling the concentration of the reactant doubles the rate. What is the order of the reaction with respect to this reactant?

Accepted Answer

First order

Question 5

Given the following rate law: $$	ext{rate} = k[\mathrm{A}]^2[\mathrm{B}]$$, what is the overall order of the reaction?

Accepted Answer

Third order

Question 6

A solution is prepared by dissolving $$0.10$$ mol of acetic acid ($$\mathrm{CH_3COOH}) in$$ $$1.0 L of $$water. The $$K_a of $$acetic acid is $$1.8 	imes 10$$^{-5}$$. What is the pH of the solution? (Assume x$$ \ll 0.10$$)

Accepted Answer

$$\mathrm{pH} \approx 2.87$$

Question 7

Which of the following best explains why a catalyst increases the rate of a chemical reaction?

Accepted Answer

A catalyst provides an alternative pathway with a lower activation energy.

Question 8

A student is asked to determine the $$K_{sp} of$$ $$\mathrm{AgCl}$$ using a saturated solution. Which of the following measurements is most directly needed?

Accepted Answer

The concentration of $$\mathrm{Ag^+}$$ ions in the saturated solution.

Question 9

In a reaction, the rate law is found to be $$	ext{rate} = k[\mathrm{NO}_2]^2. If $$the initial concentration of $$\mathrm{NO}_2 is$$ $$0.10 M $$and the rate constant $$k = 0.54\ \mathrm{M}^{-1}\mathrm{s}^{-1}$$, what is the initial rate?

Accepted Answer

$$0.0054\ \mathrm{M}\ \mathrm{s}^{-1}$$

Question 10

A buffer solution is prepared by mixing equal concentrations of acetic acid and sodium acetate. Which of the following best describes the pH of the buffer?

Accepted Answer

The pH is equal to the $$pK_a of $$acetic acid.

Question 11

During a titration, a student adds $$25.0 mL of$$ $$0.100 M $$NaOH to $$50.0 mL of$$ $$0.100 M $$HCl. What is the pH of the resulting solution?

Accepted Answer

$$\mathrm{pH} = 7.00$$

Question 12

Which of the following statements about solubility and the common ion effect is correct?

Accepted Answer

The solubility of a salt decreases in the presence of a common ion.

Question 13

A student is asked to calculate the equilibrium constant $$K_{eq}$$ for a reaction using the concentrations of products and reactants at equilibrium. Which of the following is the correct expression for $$K_{eq}$$ for the reaction $$aA + bB \rightleftharpoons cC + dD$$?

Accepted Answer

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

Question 14

In a medical laboratory, a spectrophotometer is used to determine the concentration of a colored solution. Which law relates absorbance to concentration?

Accepted Answer

Beer’s Law: $$A = \varepsilon b c$$

Question 15

A student is asked to write the balanced equation for the neutralization of sulfuric acid ($$\mathrm{H_2SO_4}) $$with sodium hydroxide ($$\mathrm{NaOH}). $$Which of the following is correct?

Accepted Answer

$$\mathrm{H_2SO_4} + 2\mathrm{NaOH} \rightarrow \mathrm{Na_2SO_4} + 2\mathrm{H_2O}$$

Question 16

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

Accepted Answer

A catalyst does not affect the equilibrium position; it only increases the rate at which equilibrium is reached.

Question 17

A student is asked to distinguish between a strong base and a weak base using pH measurements. Which of the following would be the best approach?

Accepted Answer

Measure the pH of equal concentrations of each; the strong base will have a higher pH.

Question 18

A solution contains $$0.010 M$$ $$\mathrm{Ba$$^{2+}$$}$$ and $$0.010 M$$ $$\mathrm{SO_4$^{2-}}. $$The $$K_{sp} of$$ $$\mathrm{$$BaSO_4$$} is$$ $$1.1 	imes 10$$^{-10}$$. Will a precipitate form?

Accepted Answer

Yes, because $$Q = [\mathrm{Ba$$^{2+}$$}][\mathrm{SO_4$^{2-}}] = 1.0 	imes 10$$^{-4}$$ \u003e K_{sp}.$$

Question 19

Which of the following is the correct net ionic equation for the reaction between hydrochloric acid and sodium hydroxide?

Accepted Answer

$$\mathrm{H^+} (aq) + \mathrm{OH^-} (aq) \rightarrow \mathrm{H_2O} (l)$$

General Chemistry Laboratory Study Guide: Key Concepts and Lab Skills

Guida di studio - Domande di pratica

Study guide - Flashcard