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Date May 2015 Marks available 1 Reference code 15M.1.hl.TZ1.16
Level HL Paper 1 Time zone TZ1
Command term Question number 16 Adapted from N/A

Question

Which equation represents the standard enthalpy of formation of liquid methanol?

A.     C(g)  +  2H2(g)  + 12O2(g)CH3OH(l)

B.     C(g)  +  4H(g)  +  O(g)CH3OH(l)

C.     C(s)  +  4H(g)  +  O(g)CH3OH(l)

D.     C(s)  +  2H2(g)  + 12O2(g)CH3OH(l)

Markscheme

D

Examiners report

This was a fair question with half the students answering it correctly. It was a definition question on the standard enthalpy of formation of liquid methanol but almost 40% of the candidates selected choice A where carbon is given in the gaseous state, not its solid under standard conditions.

Syllabus sections

Core » Topic 5: Energetics/thermochemistry » 5.1 Measuring energy changes
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