QCE Chemistry practice questions by topic

Original questions for every topic, with worked explanations and feedback on written answers.

Multiple choice	Worked or timed
Short response	Calculations and explanations on a stimulus
Written answers	Read against the mark points, with your next step

Try 4 questions

Question 1

A sealed flask at constant temperature initially holds only N₂O₄ gas, which reacts by N₂O₄(g) ⇌ 2NO₂(g). The graph shows the concentrations over 80 s. Which statement about the system at 60 s is supported by the graph?

Question 2

Cell potentials of metals A, B and C, each joined to a standard copper half-cell
Metal half-cell	Measured cell potential (V)	Positive electrode
A in 1 mol L⁻¹ A²⁺(aq)	1.10	copper
B in 1 mol L⁻¹ B²⁺(aq)	0.20	metal B
C in 1 mol L⁻¹ C²⁺(aq)	0.47	copper

Students in a Townsville laboratory join half-cells of three unknown metals, A, B and C, each to a standard copper half-cell, E°(Cu²⁺/Cu) = +0.34 V, and record the results in the table. Which two of the metal half-cells would make the cell with the largest E°cell, and what is that value?

Question 3

In a dimly lit laboratory, a student shakes hexane and hex-1-ene separately with orange bromine water at room temperature. Which observation is expected?

Question 4

Equilibrium percentage of ammonia at four temperatures and three pressures
Temperature (°C)	10 000 kPa	20 000 kPa	30 000 kPa
350	30	45	54
400	25	36	46
450	16	27	35
500	10	18	26

The table gives the percentage of ammonia at equilibrium for N₂(g) + 3H₂(g) ⇌ 2NH₃(g) under different conditions. An engineer needs at least 30% ammonia at equilibrium and, of the conditions that achieve this, wants the fastest rate. Which conditions in the table should she choose?

Next step

Take the free test Take the course tour

Questions people ask

Are past papers still useful?

Yes, for timing and question style. Check that a question's subject matter is in the 2025 syllabus before you rely on it.