A town collects 12 tonnes of glass. Sorting removes 8% as contamination. All remaining glass can replace virgin glass material in this simplified model.
.1
Calculate the mass available to replace virgin material.
[2 marks]
.2
Explain why reducing packaging use can give benefits beyond recycling the same mass.
[2 marks]
4 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
A plant synthesises a gas by 2X(g)+Y(g)⇌2Z(g). At the same temperature the equilibrium yield rises from 48% at low pressure to 72% at high pressure. The maximum possible product mass is 500 kg.
.1
Calculate the extra mass of Z obtained at high pressure.
[2 marks]
.2
Evaluate whether the increased yield alone proves the high-pressure process is preferable.
[2 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Students compare two catalysts for the decomposition of hydrogen peroxide. Each trial lasts 60 s; the same solution volume and concentration are available.
Plan an investigation to compare the rates fairly and assess whether a catalyst is used up.
[6 marks]
4 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
A refinery has 60 tonnes of a long-chain fraction but buyers want only 20 tonnes. Catalytic cracking converts 75% of the 40-tonne surplus into shorter fuel molecules; the rest becomes other useful products.
.1
Calculate the mass of shorter fuel molecules obtained from the surplus.
[2 marks]
.2
Explain why cracking is useful and state one chemical test that distinguishes an alkene product from an alkane.
[2 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Sewage enters a treatment works containing rags, grit, suspended organic solids and dissolved organic material. A student proposes only filtration followed by chlorination.
Explain a more complete sewage-treatment sequence and the roles of microorganisms.
