12-Week 2026 Review

Equilibrium

100

What is the equilibrium expression for
K_c of this reaction?
SnO₂ (s) + 2 CO (g) ⇌ Sn (s) + 2 CO₂ (g)

[CO²]^2
_______
[CO]²

200

K_c = 47 for the reaction
A ⇌ B.
What is K_c for the reaction
2B ⇌ 2A?

K_c = 1/(47)² = 4.5 x 10^-4

300

An equilibrium contains 0.62M N₂, 0.50M H₂, and 0.24M NH₃. What is K_c for the reaction,
N₂(g) + 3H₂(g) ⇌ 2NH₃(g)

K_c = 0.74

400

For the reaction: 2 NOCl (g) ⇌ 2 NO (g) + Cl₂ (g)

0.500 M of NOCl is placed in a reaction vessel. 0.440 mol of NOCl is found present at equilibrium. Calculate the K_c.

2x = 0.060, x = 0.030

K_c = 5.6 x 10^-4

500

ΔG° = −32.7 kJ/mol for the rxn:
N₂(g) + 3 H₂(g) ⇌ 2 NH₃ (g)

Is the rxn spontaneous forward at 100ºC if:
[N₂] = 2.00M, [H₂] = 7.00M, and [NH₃] = 0.021M?

∆G = ∆Gº + RTlnQ

= -77 kJ

Acid / Bases

100

pH of a 0.01 M NaOH solution

[OH-] = 0.01M
pOH = -log (.01) = 2
pH = 14-2 = 12

200

[OH-] if pH = 4.78

pOH = 14-pH = 9.22
[OH-]=10^-pOH = 6.0 E-10 M

300

Name the 7 strong acids.

HCl; HBr; HI; HNO₃; H₂SO₄; HClO₃; HClO₄

400

pH of a 50 mL sample of 0.005 M HF at the beginning of a titration before NaOH is added. K_a = 1.43x10^-5

ICE Table: HA <-> H₃O⁺ + A^- 
K = x²/(.005-x)
x = [H₃O⁺]
-log (x) = 3.57

500

pH of 0.005 M NH₃ (aq)
K_b = 1.43x10^-5

B <-> OH^- + BH⁺ ICE Table
K = x²/(.005-x)
x = [OH-]
pOH = -log (x); 14-pOH = pH
pH = 10.43

Buffers/Titrations

100

You would add this to a solution of ammonia (NH₃) to make it a buffer.

What is ammonium (NH₄⁺)?

200

What is the pH of a buffer solution containing 0.10 M propionic acid (C₂H₅COOH) (Ka = 1.35x10^-5) and 0.13 M of sodium propionate (NaC₂H₅OO)?

pH = pKa + log (base/acid)

pH = 4.87 + log(.13/.1)
pH = 4.98

300

What is the dominant species present at the equivalence point when titrating HNO₂ with NaOH?

NO₂^-

400

0.200 M of acetic acid (Ka = 1.8x10^-5) is titrated with 0.200 M NaOH. What is the pH at half-eq. point?

pH = pKa = 4.74

500

What is the pH for a buffer containing 1.00 mol NH₄⁺ and 1.00 mol NH₃ when 0.10 mol HCl is added? K_a = 5.9x10^-10

pH = pKa + log (base/acid)
pH = 9.22+log(0.9/1.1)
pH = 9.22 -0.0869
pH = 9.13

Salts and Ksp

100

NaNO₃ is a ______ salt.
KF is a _______ salt.
NH₄Br is a ______ salt.

neutral, basic, acidic

200

The K_sp expression for a saturated solution of Ca₃(PO₄)₂ is:

K_sp= [Ca²⁺]³[PO₄^3-]²

300

Addition of acid will _____ the solubility of BaCO₃.

increase

400

K_sp of MgF₂ = 6.4x10^-9. What is the solubility of MgF₂?

MgF₂ <-> Mg²⁺ + 2F^-
K_sp = [Mg²⁺][F^-]²
K_sp = x(2x)² = 4x³
x = 1.2x10^-3 M

500

Determine K_sp of NiCO₃ if [Ni²⁺] = 3.5x10^-4 M at equilibrium.

NiCO₃(s) <-> Ni²⁺ + CO₃^2-
K_sp = x² =(3.5E-4)²
K_sp = 1.2x10^-7

Misc. & Nav Apps

100

This is an acid that does not fully dissociate.

What is a weak acid?

200

2 NO₂ (g) <--->  N₂O₄ (g)     ΔHº = -58.0 kJ
Name 3 ways to push the rxn forward (right).

add NO₂; remove N₂O₄

increase pressure; decrease volume

decrease temperature

300

What type of titration results in a pH < 7 at equivalence point?

Titrating weak base with strong acid

400

Which direction will the reaction shift when the pressure is decreased on the following system?
3 H₂(g) + N₂(g) <--> 2 NH₃(g)

Left (reactants)

500

On a submarine, to remove CO₂:
MEA + CO₂ ⇌ MEA-CO₂
If ∆Gº = -10.2 kJ/mol, what is the equilibrium constant for this reaction at 298K?

∆Gº = -RT ln K
K = exp (-∆G/RT)
exp(--10,200/(8.314*298)) = 61.4