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 marksHigher5.6.2.5 The effect of changing concentration
AQA Trilogy 8464
Spec and skills
Paper scope: C2
Spec 5.6.2.5
Original practice question
Answer and supported method checks
An equilibrium mixture follows P+Q⇌R in solution. A process continuously removes R while fresh P and Q are supplied. Temperature is constant.
Explain why product removal can increase the total amount of R collected, and why this is not evidence that the equilibrium reaction has become irreversible.
[4 marks]
4 marksFoundation and Higher5.9.1.2 The Earth's early atmosphere
AQA Trilogy 8464
Spec and skills
Paper scope: C2
Spec 5.9.1.2
Original practice question
Answer and supported method checks
A model of early Earth’s atmosphere is based on gases from present-day volcanoes and comparisons with other rocky planets. There are no direct samples of the complete atmosphere from four billion years ago.
Evaluate the strength and limitations of this evidence.
[4 marks]
6 marksFoundation and HigherRequired practical 115.6.1.1 Calculating rates of reactions
AQA Trilogy 8464
Spec and skills
Paper scope: C2
Spec 5.6.1.1
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]
6 marksHigher5.3.2.1 Moles
AQA Trilogy 8464
Spec and skills
Paper scope: C1
Spec 5.3.2.1
Original practice question
Answer and supported method checks
Two separate samples each have mass 8.0 g. One is oxygen gas, O2, and the other is sulfur dioxide, SO2.Ar: O = 16, S = 32.
.1
Calculate the amount of oxygen molecules in the oxygen sample.
[2 marks]
.2
Calculate the amount of sulfur dioxide molecules in its sample.
[2 marks]
.3
Explain which sample contains more molecules and by what factor.
