Question

Rolls
Which reaction shows that the enthalpy of formation of C2H4 IS A Hp = 52.5
kJ/mol?

Answer 1

Answer: 2C(s) + 2H₂(g) + 52.5 kJ → C₂H₄

Answer 2

A. 2C(s) + 2H₂(g) + 52.5 kJ → C₂H₄ shows that the enthalpy of formation of C₂H₄ is 52.5 kJ/mol.

Explanation:

Enthalpy of formation of C₂H₄ is given as 52.5 kJ/mol.

There are 4 options given and they are:

A. 2C(s) + 2H₂(g) + 52.5 kJ → C₂H₄

B. 2C(s) + 4H(g) + 52.5 kJ → C₂H₄

C. 2C(s) + 2H₂(g) → C₂H₄ + 52.5 kJ

D. 2C(s) + 4H(g) → C₂H₄ + 52.5 kJ

Here the reactants absorb some energy from the surroundings and gives the product and it is an endothermic reaction.

So A and B is taken into account, but in B there are 4 H atoms involved in the reaction. So in the reaction A hydrogen molecules are involved and also energy is absorbed by the reactants.

So option A is the answer.