Question

2C(s) + 2H2(g) → C2H4(g): ΔH = +52.4 kJ/mol

Which statement about this reaction is correct?

Answer 1

Answer;

26.2 kJ of energy are absorbed for every mole of carbon reacted

Explanation;

• ΔH is the enthalpy change which is given by subtracting the energy of reactants from the energy of products.
• That is; ΔH = energy of products - energy of reactants
• In this case, it means that C2H4 has more energy than the the reactants. 52.4 J of energy to be precise, this energy is absorbed during the reaction.
• However, Two moles of Carbon  require that much energy, thus one mole will require only 26.2 to react.

Answer 2

Answer: D) 26.2 kJ of energy are absorbed for every mole of carbon reacted.