Question

When 1 mole of H2(g) reacts with F2(g) to form HF(g) according to the following equation, 542 kJ of energy are evolved H2(g) + F2(g2HF(g) Is this reaction endothermic or exothermic? What is the value of q?

Answer 1

Answer: The reaction is exothermic. The value of q is  -542 kJ.

Explanation:

Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and  for the reaction comes out to be positive.

Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and  for the reaction comes out to be negative.

Thus $H_2(g)+F_2(g)\rightarrow 2HF(g)$ evolves heat , it is exothermic in nature. The value of q is -542kJ.