Select all the correct answers,
based on the enthalpy changes given for the reactions, which reactions are endothermic?

The reaction for which ΔH is positive are endothermic reactions.

Explanation:

The energy changes occur during the bonds formation and bonds breaking.

There ere two types of reaction endothermic and exothermic reaction.

Endothermic reactions:

The type of reactions in which energy is absorbed are called endothermic reactions.

In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.

For example:

C + H₂O   →  CO  + H₂

ΔH = +131 kj/mol

it can be written as,

C +  H₂O  + 131 kj/mol  →  CO  + H₂