Edexcel · Timed mock · 2 hours 30 minutes · 120 marks
An original practice paper with the same length, timing and style as Edexcel A-level Paper 3: synoptic questions from across the course, with a strong focus on the core practicals and data analysis.
Before you start
- Answer all questions. You have 2 hours 30 minutes and the paper is worth 120 marks.
- All questions are written questions. Allow a little over one minute per mark, leaving time to check.
- You need a calculator, a periodic table and the data booklet. Any other data you need is given in the question.
- Type your answers in the boxes, or write on paper. Answers typed here are saved in this browser as you go.
- Show your working in calculations: most marks are for the method.
- When you finish, or when time is up, press Finish and mark, then give yourself a mark for each part using the mark scheme.
Here is the first question so you can see the style. The full paper, the timer and the mark scheme are part of Premium.
A student used Hess's law to find the enthalpy change for 2KHCO3(s) → K2CO3(s) + CO2(g) + H2O(l).
Experiment 1: 3.00 g of KHCO3 (Mr 100.1) was added to 30.0 cm3 of 2.0 mol dm−3 HCl (excess) in a polystyrene cup. The temperature fell by 5.2 °C.
Experiment 2: 2.76 g of K2CO3 (Mr 138.2) was added to 30.0 cm3 of the same acid. The temperature rose by 5.4 °C.
Specific heat capacity of the solution = 4.18 J g−1 °C−1.
Calculate ΔH, in kJ mol−1, for KHCO3 + HCl → KCl + CO2 + H2O.
Calculate ΔH, in kJ mol−1, for K2CO3 + 2HCl → 2KCl + CO2 + H2O.
Calculate ΔH for the decomposition of KHCO3.
State two assumptions made in your calculation.
Suggest two improvements to make the results more accurate.
Each thermometer reading is ±0.1 °C. Calculate the percentage uncertainty in the temperature change in Experiment 1.
The full 120-mark paper is part of Premium, with a countdown timer, instant marking of the multiple-choice questions and a full mark scheme for the rest.
This is an original paper written for this site in the style and length of the real exam. It is not a past paper, and this site is not endorsed by AQA or Pearson Edexcel.