Question 1
Pure N₂O₄ is sealed in a flask at constant temperature and reacts: N₂O₄(g) ⇌ 2NO₂(g). The graph shows the concentrations of both gases. What is the value of Kc at this temperature?
The SACE Chemistry exam
The examination is 30% of the subject: one 130-minute paper of 120 marks in two question booklets of about 65 minutes each. Questions come in parts of different types, with no multiple choice, and a periodic table and data sheet are provided.
| The examination | 30% of the subject: one 130-minute examination, 120 marks |
|---|---|
| Booklets | Two question booklets, about 65 minutes each |
| Questions | Questions in parts of different types; no multiple choice |
| Provided | A periodic table and data sheet; approved calculators allowed |
| School assessment | 70%: investigations folio 30%, skills and applications tasks 40% |
What the examination asks
- Questions in several parts: equations, explanations, calculations with working, diagrams, and reading data from investigations.
- Some questions draw on more than one topic, and some on science as a human endeavour.
- The data sheet gives a periodic table, SI prefixes, the relationships n = m/M, c = n/V, Q = mcΔT, ΔH = Q/n and pH = −log[H⁺], and the metal activity series. Any other value a question needs is given in the question.
Write to the question
- For a calculation, write each step with its formula, carry the units and give the answer to sensible significant figures.
- For an equation, balance atoms and charge and give state symbols where they matter.
- For explain, give the point, tie it to the substance, conditions or data in the question, then say what it causes.
Try 2 questions
Question 2
| Fuel | ΔcH (kJ mol⁻¹) | M (g mol⁻¹) | Density (g mL⁻¹) |
|---|---|---|---|
| ethanol | −1367 | 46.07 | 0.789 |
| octane | −5470 | 114.22 | 0.703 |
A fleet manager compares ethanol with octane, the main component of petrol, as fuels, using the data in the table. How many times as much heat does one litre of octane release as one litre of ethanol, when each burns completely?
Next step
Questions people ask
Does the SACE Chemistry exam have multiple choice?
No. Every question is answered in writing, in parts. Our four-option questions and timed checks are the course's own way to practise the ideas quickly.
Can I use a calculator?
Yes, an approved calculator, and the periodic table and data sheet are provided.