Equilibrium & Acids/Bases Master Knowt

What is the pOH of a 5.1 M solution of HCl?

14.71

Which acid is stronger: HClO₂ or HClO₃?

HClO₃

What is the concentration of hydroxide ions in a solution with pH of 6.19?

1.5 × 10⁻⁸ M

What is the percent ionization of 0.25 M ammonia (Kb = 1.8×10⁻⁵)?

0.85%

Given [OH⁻] = 1.3×10⁻⁶ M for 0.025 M weak base, what is pKb?

10.17

For 0.54 M HNO₂ (Ka=4.0×10⁻⁴), what is the calculated pH?

1.83

When solid NaCN is added to water, what happens to the pH?

Becomes greater than 7 (hydrolysis of CN⁻)

Calculate [H⁺] for a solution with pH = 2.84.

1.4 × 10⁻³ M

A 2.4 M weak acid is 0.52% ionized. What is Ka?

6.5 × 10⁻⁵

What is the pH of a 0.045 M solution of Ca(OH)₂?

12.95

For weak acid HX (Ka=5.1×10⁻⁶, 0.17 M), what is the calculated pH?

3.03

What is the percent ionization of 0.20 M HNO₂ (Ka=4.5×10⁻⁴)?

2.8%

Calculate [OH⁻] in 0.015 M CH₃COOH (Ka=1.8×10⁻⁵).

1.9 × 10⁻¹¹ M

If solid Ca(OH)₂ is dissolved until pH = 11.50, what is [OH⁻]?

3.2 × 10⁻³ M

Rank in decreasing acid strength: HCl, HOCl, HOBr, HOI.

HCl > HClO > HBrO > HIO

Which is the weakest base from the given pKa values?

ClO₂⁻

What is the incorrect statement about HCl vs HF?

Only III

What is the pOH of 0.74 M CH₃COOH (Ka=1.8×10⁻⁵)?

11.56

Which of the following cannot act as a Lewis base?

NH₄⁺

For 7.97 M HCOOH that is 0.47% ionized, what is Ka?

1.8 × 10⁻⁴

Calculate the pOH of 0.16 M Ba(OH)₂.

0.49

What is the pH of a 0.271 M HNO₃(aq)?

0.567

A weak acid is 0.66% dissociated with pH=3.04. Find Ka.

6.1 × 10⁻⁶

Calculate the pH of 0.03 M KOH.

12.5

At 60°C, Kw = 9.25×10⁻¹⁴. What is the pH of pure water?

6.617

A solution with pH = 1.6 would be described as:

Very acidic

Calculate the pH of 0.10 M NH₃ (Kb = 1.8×10⁻⁵).

11.12

What is [H₃O⁺] when pOH = 3.62?

4.2 × 10⁻¹¹ M

Match the molecule HClO with its conjugate base.

ClO⁻

What is the pKa when [H₃O⁺] = 2.0×10⁻⁴ M for 0.020 M weak acid?

3.70

Is the autoionization of water endothermic?

Yes, as temperature increases, pH decreases and water remains neutral.

For the equilibrium where [H₃O⁺] and [OH⁻] is calculated in 0.050 M Ba(OH)₂, what are the values?

[H₃O⁺]=1.0×10⁻¹³ M, [OH⁻]=0.10 M

What is the relationship between Kc for CH₄ + H₂O ⇌ CO + 3H₂, given equilibrium data?

42

For the reaction 4NOCl + 2Br₂ ⇌ 4NO + 4BrCl, what is Kc?

1.63

What happens when AgNO₃ is added to Fe³⁺ + SCN⁻ ⇌ FeSCN²⁺?

Shifts right.

What is the reaction quotient (Qc) for Fe³⁺ + SCN⁻ ⇌ FeSCN²⁺?

Qc = [FeSCN²⁺] / ([Fe³⁺][SCN⁻])

Calculate Kc for Fe³⁺ + SCN⁻ ⇌ FeSCN²⁺ given moles in 3 L.

364.8

What are the concentration change terms for 3O₂ ⇌ 2O₃?

O₂: –3x, O₃: +2x

What is the new concentration of [C] if volume is doubled at 200°C for A(g) ⇌ B(g) + C(g)?

0.29 M

What is the best definition of chemical equilibrium?

Forward and reverse reaction rates are equal and constant.

For the reaction I₂(g) ⇌ 2I(g), what happens to [I₂] if the temperature is increased?

[I₂] decreases.

What happens to Kp when the temperature increases for an endothermic reaction?

Kp increases.

What happens to Kp when the temperature increases for an exothermic reaction?

Kp decreases.

For 2NO₂(g) ⇌ N₂O₄(g), what happens when pressure is increased?

Shifts toward N₂O₄ (fewer moles of gas).

What happens when pressure decreases for the same equilibrium, 2NO₂(g) ⇌ N₂O₄(g)?

Shifts toward NO₂ (more moles of gas).

What changes affect the value of Kc?

Temperature only.

What happens to equilibrium when a catalyst is added?

Equilibrium is reached faster; K does not change.

What happens to concentrations of reactants and products at equilibrium when a catalyst is added?

No change.

For N₂(g) + 3H₂(g) ⇌ 2NH₃(g), what happens when H₂ is removed?

Shifts left.

For the same reaction, what happens when NH₃ is removed?

Shifts right.

For N₂(g) + 3H₂(g) ⇌ 2NH₃(g), what happens when N₂ is added?

Shifts right.

For N₂(g) + 3H₂(g) ⇌ 2NH₃(g), what happens when pressure increases?

Shifts right.

For N₂(g) + 3H₂(g) ⇌ 2NH₃(g), what happens when pressure decreases?

Shifts left.

For N₂(g) + 3H₂(g) ⇌ 2NH₃(g), what happens when temperature increases?

Shifts left (endothermic reverse reaction favored).

For N₂(g) + 3H₂(g) ⇌ 2NH₃(g), what happens when temperature decreases?

Shifts right (exothermic forward reaction favored).

What is the relationship between Kp and Kc?

Kp = Kc(RT)Δn.

For N₂O₄(g) ⇌ 2NO₂(g), how does the color change when temperature increases?

Becomes darker brown (more NO₂ formed).

For the same reaction, what happens when the mixture is cooled?

Becomes lighter (more N₂O₄ formed).

What occurs when pressure is increased for N₂O₄ ⇌ 2NO₂?

Shifts left (fewer gas moles).

What happens when pressure decreases for N₂O₄ ⇌ 2NO₂?

Shifts right (more gas moles).

What happens to the equilibrium constant when the temperature is changed?

K changes only with temperature.

What happens to equilibrium concentrations when a solid is added?

No effect.

For a reaction at equilibrium, what happens if more catalyst is added?

No shift; equilibrium is reached faster.

At equilibrium, what is true about the forward and reverse reaction rates?

They are equal.

When a stress is applied to a system at equilibrium, how does the system respond?

It shifts to counteract the change (Le Châtelier’s Principle).

What happens to the value of K when pressure or concentration changes?

K remains constant