chem exam 2

Which property is not associated with an acid?

has a bitter taste

The conjugate acid of CO₃^2- is HCO₃⁻  

True

The conjugate base of H₂PO₄⁻ is H₃PO₄

false

Consider the three generic weak acids HA, HB, and HC. The images shown here represent the ionization of each acid at room temperature. Which acid has the largest Ka?

HB

Consider the following acids and their dissociation constants,

H₂SO₃(aq) + H₂O(l)  ⇄ H₃O⁺(aq) + HSO³⁻(aq)  Ka=1.2×10⁻²

HS⁻(aq) + H₂O(l)  ⇄ H₃O⁺(aq) + S²⁻(aq)  Ka=1.3×10⁻¹⁹

Which is the stronger acid, H₂SO₃ or HS⁻?

H₂SO₃

Water is amphoteric because it can act as an acid and a base. True/False?

True

Calculate [OH⁻] at 25 °C for each solution and determine if the solution is acidic, basic, or neutral.

[H₃O⁺] = 7.5 × 10⁻⁵ M

acidic

If a solution has a pH of 3, is it considered acidic, basic, or neutral?

acidic

If a solution has a pOH of 3, is it considered acidic, basic, or neutral?

basic

Find the pH of a 0.0010 M HCl solution.

3

Determine the pH of a 0.025 M sulfuric acid (H₂SO₄) solution.

1.3

Find the [H3O+] of a 0.100 M HCN solution. Ka of the acid is 4.9 x 10-10

7.0×10⁻⁶

Find the pH of a 0.0010 M NaOH solution.

11

Find the pH of a 0.225 M KOH solution.

13.35

Find the pH of a 0.100 M NH3 solution. Kb of the base is 1.76 x 10-5.

11.12

C₅H₅NH⁺

Classify this cation as a weak acid or pH-neutral

weak acid

Determine if the solution formed by below salt is acidic, basic, or neutral:

CH₃NH₃NO₃

acidic

HNO₃ has a greater acidity than HNO₂. True/False?

true

Which of the following is an Arrhenius base?

KOH

Which of the following is a Br∅nsted-Lowry base?

H₂O

What is the conjugate acid of H₂PO₄^⁻?

H₃PO₄

Which of the following is NOT a conjugate acid-base pair?

NH₄⁺/NH_2-

Which of the following species is amphoteric?

HPO₄^2-

Arrhenius acid

produce protons in aqueous solution

Arrhenius base

produce hydroxyl ions in aqueous solution

Bronsted-Lowry acid

proton donor

Bronsted-Lowry base

proton acceptor

Calculate the concentration of H₃O^⁺ in a solution that contains 2.5 × 10^-5 M OH^⁻ at 25°C. Identify the solution as acidic, basic or neutral.

4.0 × 10^-10 M, basic

Which of the following acids is the strongest? The acid is followed by its K_a value.

 HClO₂, 1.1 × 10^-2

What is the concentration of hydroxide ions in pure water at 30.0^∘C, if K_w at this temperature is 1.69 × 10^-14?

1.30 × 10^-7 M

Give the characteristics of a strong acid.

• has a large K_a value

• ionizes completely in aqueous solutions

• has equilibrium far to the right

• has a weaker bond to hydrogen

• all of the above

What is the K_w of pure water at 50.0°C, if the pH is 6.630?

5.50 × 10^-14

Which of the following is a Br∅nsted-Lowry acid?

NH₄⁺

What is the conjugate base of HPO_4²⁻ ?

PO₄^3-

Which of the following solutions would have the highest pH? Assume that they are all 0.10 M in acid at 25^∘C. The acid is followed by its K_a value.

HC₆H₅O, 1.3 × 10^-10

Identify the products when hydrochloric acid completely ionizes in water.

H₃O+ and Cl^-

Identify the products that are in equilibrium with NH₃ and H₂O.

NH₄⁺ and ^-OH

Which of the following statements is TRUE?

The conjugate base of a very weak acid is stronger than the conjugate base of a strong acid.

What is the pH of pure water at 40.0°C if the K_w at this temperature is 2.92 × 10^-14?

6.767

Which of the following is TRUE?

An acidic solution has [H₃O⁺] > [OH⁻].

What is the K_w of pure water at 50.0°C, if the pH is 6.630?

5.50 × 10^-14

Calculate the hydronium ion concentration in an aqueous solution with a pH of 9.85 at 25°C.

1.4 × 10^-10 M

Calculate the concentration of H₃O⁺ in a solution that contains 1.8 × 10^-5 M OH⁻ at 25°C. Identify the solution as acidic, basic, or neutral.

5.5 × 10^-10 M, basic

Calculate the hydroxide ion concentration in an aqueous solution with a pH of 9.85 at 25°C.

7.1 × 10^-5 M

Determine the pH of a 0.033 M HNO₃ solution

1.48

Calculate the hydroxide ion concentration in an aqueous solution with a pOH of 8.85 at 25°C.

1.4 × 10^-9 M

Calculate the pH of a solution that contains 7.8 × 10^-6 M OH⁻ at 25°C.

8.89

Calculate the hydronium ion concentration in an aqueous solution with a pOH of 4.33 at 25°C.

2.1 × 10^-10 M

Identify the strongest acid.

2.00 M HCl

Determine the [H₃O⁺] concentration for a 0.200 M solution of HCl.

2.00 × 10^-1 M

Find the percent ionization of a 0.337 M HF solution. The K_a for HF is 3.5 × 10^-4.

3.2%

Determine the pH of a 0.461 M C₆H₅CO₂H M solution if the K_a of C₆H₅CO₂H is 6.5 × 10^-5.

2.26

Determine the K_a of an acid whose 0.294 M solution has a pH of 2.80.

8.5 × 10^-6

Place the following in order of increasing acid strength.

HBrO HBrO2 HBrO4 HBrO4

HBrO < HBrO₂ < HBrO₃ < HBrO₄

A Lewis base

donates an electron pair

Determine the [H₃O⁺] in a 0.265 M HClO solution. The K_a of HClO is 2.9 × 10^-8.

8.8 × 10^-5 M

Which of the following bases is the weakest? The base is followed by its K_b value.

C₅H₅N, 1.7 × 10^-9

Which one of the following salts, when dissolved in water, produces the solution with the highest pH?

CaO

Which one of the following salts, when 1 mole is dissolved in water, produces the solution with a pH closest to 7.00?

KCl

Which of the following is a Lewis acid?

AlBr₃

Which of the following is a Lewis base?

H₂S

If the pKa of HCHO₂ is 3.74 and the pH of an HCHO₂/NaCHO₂ solution is 3.00, which of the following is TRUE?

[HCHO₂] > [NaCHO₂]