ChemIIA 2012 final.pdf
Chemistry IIA, IIA(Ecochem), IIA(Mol Drug Des), IIA(Nanosci Mat) June 2012
Allow 45 minutes for this section of the paper. Answer in a separate booklet. Total marks = 30
Calculate the entropy change for burning 1 kg of n-octane(g) to H2O(l) and CO2(g) at 298 K and 1 atm.
One mole of an ideal monatomic gas is expanded from an initial state of 2 atm and 400 K to a final state
of 1 atm and 300 K. Calculate S for the following paths:
Isothermal expansion against 1 atm at 400 K, followed by an isobaric decrease in T to 300 K.
[Total for question 1 = 8 marks]
Calculate the work done at 298.15 K when 1 mole of an ideal gas expands isothermally from 400 kNm-2
to 150 kNm-2 in one stage by a sudden direct reduction in pressure to 150 kNm-2.
Calculate the work done at 298.15 K when 1 mole of an ideal gas expands isothermally by having a
large series of infinitesimal decreases of pressure over a long period from 400 kNm-2 to 150 kNm-2.
[Total for question 2 = 4 marks]
One mole of an ideal monatomic gas is expanded from an initial state of 4 atm and 300 K to a final state
of 2 atm and 300 K. Calculate G for this expansion.
Using the thermodynamic information provided, determine which set of products will be most favoured?
Show your work clearly to receive full credit.
H 2O2 ( g )
2OH ( g ) H 2O( g ) 0.5O2 ( g )
OH ( g ) OH ( g )
Gof(298 K) kJmol-1
[Total for question 3 = 8 marks]
Course ID. 104311, 104312, 104313, 104314
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