Q: A solution has $$[H_3O^+] = 2.0 \times 10$$^{-4}$$\ \mathrm{M}. $$What is the pH of this solution?

$$\mathrm{pH} = -\log(2.0 \times 10$$^{-4}$$) = 3.70$$

Q: A student titrates 25.00 mL of H2SO4 with 0.200 M NaOH. It takes 50.00 mL of NaOH to reach the equivalence point. What is the concentration of the H2SO4 solution? (Assume complete dissociation.)

$$\mathrm{M}_1 \times V_1$ \times 2 = M_2$ \times V_2$; M_1$ = \frac{0.200 \times 0.05000}{2 \times 0.02500} = 0.200\ \mathrm{M}$$

Q: A swimming pool has a pH of 7.4. What is the concentration of hydroxide ions, $$[OH^-]$$, in the pool?

$$[OH^-] = 10$$^{-6.6}$$ = 2.5 \times 10$$^{-7}$$\ \mathrm{M}$$

Question 1

Which of the following best describes the difference between a strong acid and a weak acid, according to their behavior in water?

Accepted Answer

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

Question 2

Which equation correctly represents the neutralization reaction between hydrochloric acid and sodium hydroxide?

Accepted Answer

$$\mathrm{HCl\ (aq) + NaOH\ (aq) \rightarrow NaCl\ (aq) + H_2O\ (l)}$$

Question 3

A solution has $$[H_3O^+] = 2.0 	imes 10$$^{-4}$$\ \mathrm{M}. $$What is the pH of this solution?

Accepted Answer

$$\mathrm{pH} = -\log(2.0 	imes 10$$^{-4}$$) = 3.70$$

Question 4

Which of the following statements about the Arrhenius and Brønsted–Lowry definitions of acids and bases is correct?

Accepted Answer

The Brønsted–Lowry definition applies to a wider range of acid–base reactions than the Arrhenius definition.

Question 5

A student titrates 25.00 mL of H2SO4 with 0.200 M NaOH. It takes 50.00 mL of NaOH to reach the equivalence point. What is the concentration of the H2SO4 solution? (Assume complete dissociation.)

Accepted Answer

$$\mathrm{M}_1 	imes V_1$ 	imes 2 = M_2$ 	imes V_2$; M_1$ = \frac{0.200 	imes 0.05000}{2 	imes 0.02500} = 0.200\ \mathrm{M}$$

Question 6

Which of the following best explains why strong acids and bases are strong electrolytes?

Accepted Answer

They completely dissociate into ions in solution, allowing electricity to flow.

Question 7

What is the pOH of a solution with a pH of 5.25 at 25°C?

Accepted Answer

$$\mathrm{pOH} = 14 - 5.25 = 8.75$$

Question 8

Which of the following is an example of water acting as a Brønsted–Lowry base?

Accepted Answer

$$\mathrm{HCl\ (aq) + H_2O\ (l) \rightarrow H_3O^+\ (aq) + Cl^-\ (aq)}$$

Question 9

A swimming pool has a pH of 7.4. What is the concentration of hydroxide ions, $$[OH^-]$$, in the pool?

Accepted Answer

$$[OH^-] = 10$$^{-6.6}$$ = 2.5 	imes 10$$^{-7}$$\ \mathrm{M}$$

Question 10

Which of the following best describes the role of ammonia (NH3) in water according to the Brønsted–Lowry theory?

Accepted Answer

NH3 acts as a base by accepting a proton from water.

Question 11

Which of the following is the correct net ionic equation for the neutralization of HBr with KOH?

Accepted Answer

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

Question 12

A solution has $$[OH^-] = 3.2 	imes 10$$^{-5}$$\ \mathrm{M}. $$What is the pOH of the solution?

Accepted Answer

$$\mathrm{pOH} = -\log(3.2 	imes 10$$^{-5}$$) = 4.49$$

Question 13

Which of the following statements about the ion product constant for water ($$K_w) at 25$$°C is correct?

Accepted Answer

$$K_w = [H_3O^+][OH^-] = 1.0 	imes 10$$^{-14}$$

Question 14

Which of the following best describes a conjugate acid–base pair?

Accepted Answer

They differ by one proton ($$H^+).$$

Question 15

A student adds a strong acid to pure water. Which of the following changes will occur?

Accepted Answer

The $$[H_3O^+]$$ will increase and the $$[OH^-]$$ will decrease.

Question 16

Which of the following is a property of bases?

Accepted Answer

They turn red litmus paper blue.

Question 17

Which of the following best describes the endpoint in an acid–base titration?

Accepted Answer

The point at which the indicator changes color.

Acids and Bases: Definitions, Properties, and Calculations

Guida di studio - Domande di pratica

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