| Date | May 2017 | Marks available | 1 | Reference code | 17M.1.sl.TZ2.14 |
| Level | SL | Paper | 1 | Time zone | TZ2 |
| Command term | State | Question number | 14 | Adapted from | N/A |
Question
Why is the value of the enthalpy change of this reaction calculated from bond enthalpy data less accurate than that calculated from standard enthalpies of formation?
2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g)
A. All the reactants and products are gases.
B. Bond enthalpy data are average values for many compounds.
C. Elements do not have standard enthalpy of formation.
D. Standard enthalpies of formation are per mole.
Markscheme
B
Examiners report
[N/A]
