(Total 11 marks)
Q1
(a) M1 6CO2 + 6H2O → C6H12O6 + 6O2
1
M2 C6H12O6 → 2C2H5OH + 2CO2
Allow C2H6O for ethanol formula
1
M3 2C2H5OH + 6O2 → 4CO2 + 6H2O
M1/2/3 allow multiples
M3 C2H5OH + 3O2 → 2CO2 + 3H2O
1
M4 explains with reference to relevant equations that formation of C6H12O6 takes in 6CO2 and fermentation and combustion of ethanol gives out 6CO2
M4 depends on having appropriate equations in M1/2/3 showing 6 CO2 in and out
1
(b) transport (from South America to Europe) produces CO2 / has C emissions / has larger C footprint
Process to separate ethanol from propanone and butan-1-ol produces CO2 / has C emissions / has larger C footprint
1
(c) M1 685.5 (686), 668(.25), 595(.33…) in third column of table
M1 ignore any minus sign on values
1
M2 depends on their answer to M1 − must be the compound giving most energy per mole of CO2 released (correct M1 would give ethanol)
M2 need evidence of attempt to calculate energy released per C atom (i.e. per mole of CO2 formed)
1
(d) M1 amount propanone = 
(=0.0203 mol)
1
M2 q = M1 × 1786 (= 36.3 kJ = 36300 J)
1
M3 ΔT (=
) = 33.4 (°C) (allow 32.8-33.4)
M3 ignore sign
1
M4 final temperature = (22.3 + M3) = 55.7 (°C) (allow 55-596)
M4 must show a temperature rise
1
Correct answer scores 4 marks
Allow ECF at each stage
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