Quick answer: The amount of substance, in mol, links mass, particle number, solution volume and gas volume. This Chemistry 11-12 test on ideal gas equation has 8 questions worth 20 marks, to do in 45 minutes: mass of potassium carbonate, formula of an oxide of lead and graph of gas volume. The mark scheme is on a separate page; free printable PDF.
This test covers moles, formulae, the ideal gas equation, atom economy and yield. Show your working and give units. Use R = 8.31 J K⁻¹ mol⁻¹ where needed. The total is 20 marks.
Level: Chemistry grades 11-12 (A Level · IB · Class 11-12) · Curriculum: A Level 3.1.2
Question 1 Mass of potassium carbonate (2 marks)
Calculate the mass of 0.0300 mol of potassium carbonate, K₂CO₃ (Ar: K 39.1, C 12.0, O 16.0). (2 marks)Question 2 Formula of an oxide of lead (3 marks)
A sample of an oxide of lead contains 2.07 g of lead and 0.32 g of oxygen (Ar: Pb 207, O 16.0). Calculate its empirical formula. (3 marks)Question 3 Graph of gas volume (4 marks)
The graph shows the volume of a fixed amount of gas at 100 kPa.- Read the volume at 300 K. (1 mark)
- State the relationship between V and T. (1 mark)
- Calculate the amount of gas, using the point at 400 K. (2 marks)
Question 4 Atom economy of oxygen (3 marks)
Hydrogen peroxide decomposes: 2H₂O₂ → 2H₂O + O₂. The useful product is oxygen (Mr: H₂O₂ 34.0, H₂O 18.0, O₂ 32.0). Calculate the atom economy and say whether it is high or low. (3 marks)Question 5 Molecular formula (2 marks)
A hydrocarbon has empirical formula CH₂ and relative molecular mass 84.0. Deduce its molecular formula. (2 marks)Question 6 Volume of a gas (3 marks)
Calculate the volume in dm³ of 0.500 mol of an ideal gas at 300 K and 200 kPa (R = 8.31 J K⁻¹ mol⁻¹). (3 marks)Question 7 Percentage yield (2 marks)
A chemist expects 6.00 g of product but obtains 4.50 g. Calculate the percentage yield. (2 marks)Question 8 Why atom economy matters (1 mark)
State one advantage of a reaction with a high atom economy. (1 mark)
