Which describes the enthalpy change associated with an endothermic reaction?
it is negative because the enthalpy of the products is greater than the enthalpy of the reactants.
it is positive because the enthalpy of the products is greater than the enthalpy of the reactants.
it is negative because the enthalpy of the reactants is greater than the enthalpy of the products.
it is positive because the enthalpy of the reactants is greater than the enthalpy of the products.

It is positive because the enthalpy of the products is greater than the enthalpy of the reactants.

Explanation:

1) Per definition, enthalpy of the reaction = enthalpy change

2) Per definition,

enthalpy change = ∑ enthalpy of the products - ∑ entalphy of the reactants

3) Per definition, endothermic reaction ⇒ heat is absorbed

4) heat absorbed ⇒ ∑ enthalpy of the products > ∑ entalphy of the reactants

5) ∑ enthalpy of the products > ∑ entalphy of the reactants ⇒

∑ enthalpy of the products - ∑ entalphy of the reactants > 0

6) ⇒ enthalpy change > 0

Therefore, it has been shown that enthalpy change in and endothermic reaction is positive since the enthalpy of the products is greater than the enthalpy of the reactants.

it is letter B

It is positive because the enthalpy of the products is greater than the enthalpy of the reactants.

you're welcome

nuclear fission produces elements that are heavier than helium.

the elements that are used in nuclear fission and their products are much heavier than helium.