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Date November 2014 Marks available 1 Reference code 14N.1.hl.TZ0.18
Level HL Paper 1 Time zone TZ0
Command term Question number 18 Adapted from N/A

Question

Consider the values of \(\Delta {H^\Theta }\) and \(\Delta {S^\Theta }\) À for the reaction of nitrogen with oxygen at 298 K.

     \({{\text{N}}_{\text{2}}}{\text{(g)}} + {{\text{O}}_{\text{2}}}{\text{(g)}} \to {\text{2NO(g)}}\)     \(\Delta {H^\Theta } =  + 181{\text{ kJ}}\,{\text{mo}}{{\text{l}}^{ - 1}}\)

          \(\Delta {S^\Theta } =  + 25{\text{ J}}\,{{\text{K}}^{ - 1}}{\text{mo}}{{\text{l}}^{ - 1}}\)

Which statement is correct for this reaction?

A.     \(\Delta {G^\Theta }\) is positive at all temperatures.

B.     \(\Delta {G^\Theta }\) is negative at all temperatures.

C.     \(\Delta {G^\Theta }\)  is positive at high temperatures.

D.     \(\Delta {G^\Theta }\) is positive at low temperatures.

Markscheme

D

Examiners report

[N/A]

Syllabus sections

Additional higher level (AHL) » Topic 15: Energetics/thermochemistry » 15.1 Energy cycles
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