Question: What is the enthalpy change for the reaction: C(s) + O2(g) → CO2(g) if the standard enthalpy of formation of CO2 is -393.5 kJ/mol?

Options:

1. -393.5 kJ/mol
2. 393.5 kJ/mol
3. 0 kJ/mol
4. Not enough information

Correct Answer: -393.5 kJ/mol

Solution:

The enthalpy change for the formation of CO2 from its elements in their standard states is equal to the standard enthalpy of formation, which is -393.5 kJ/mol.