A student measures an enthalpy change of for the reaction at

CHEMISTRY · Subjective · A Level · Chemistry · Energetics · Energetics

Problem

A student measures an enthalpy change of

-184\,\text{kJ}

for the reaction

2\,\mathrm{SO_2(g)} + \mathrm{O_2(g)} \rightarrow 2\,\mathrm{SO_3(g)}

298\,\text{K}

. Reference tables list

-198\,\text{kJ}

for the same reaction under standard conditions. Does the student’s result violate the first law of thermodynamics? Briefly state your reasoning and give one plausible experimental factor that could account for the

14\,\text{kJ}

difference.

Related theory

Thermodynamics
Calorimetry
Heat capacity and work
Measurement of $\Delta U$ and $\Delta H$

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