Chem Enthalpy

Test Preparation SAT Subject Test Preparation
1

<p>My question is about the theory of enthalpy. First its established that if the change in enthalpy is less than 0 it is an exothermic reaction and energy is released.</p>

<p>But the formula is "Change of Enthalpy" = Enthalpy of products-Enthalpy of reactants.</p>

<p>I would have believed that with a release of energy, there is more heat in the product thus when using this equation, an exothermic reaction would actually have a positive enthalpy. But in reality, it is negative. Can anybody explain why this is the case?</p>

2

<p>If heat is released from the reactant(s) as it is converted to product(s), the product(s) will have less heat than they started out with. The heat is released to the environment; so the surroundings would gain some energy, but the products would be at a lower enthalpy than the reactants.</p>