What is known about a reaction with a positive enthalpy?
A. Heat is given off as a product of the reaction.
B. The reaction has a large activation energy.
OC. Heat is required to make the reaction occur.
OD. The reaction will never be spontaneous.
In endothermic reactions, enthalpy is positive, and in exothermic reactions, enthalpy is negative, So, if enthalpy is positive, then it is an endothermic reaction, and hence is required for the reaction to occur.