alleryStart learning →How much heat is produced by burning 4.00 mol of acetylene, whose enthalpy of combustion is -1301.1 kJ/mol?
A325 kJ
B1301 kJ
C2602 kJ
D5204 kJ
Answer & Solution
Correct answer: D. 5204 kJ
1. The tabulated value gives minus 1301.1 kJ for every 1 mol of acetylene burned.
2. Enthalpy change is extensive, so multiply by the number of moles burned.
3. That is 4.00 mol times minus 1301.1 kJ per mole.
4. The product is minus 5204.4 kJ, so about 5204 kJ of heat is produced.
5. Dividing rather than multiplying by 4.00 gives 325 kJ, the reversed-factor trap.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 5 "Thermochemistry", section 5.3 Enthalpy_
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