Paper 3 · June 2009 · Thermochemistry and Energetics
Which statement is true about the enthalpy change of atomisation?
AIt has a positive value.
BIt has a negative value.
CIt is usually found directly from experiments.
DIt is the same as bond energy.
Explanation
The marking scheme gives answer A. The standard enthalpy of atomisation is always endothermic (positive) because energy must be supplied to break bonds and convert an element into gaseous atoms.
ZIMSEC Chemistry Paper 3, June 2009, Q26