A student conducting a calorimetry investigation determines a negative ∆H. What does the negative value indicate about the reaction?

Answer : The negative value indicate about the reaction is exothermic and heat is released.

Explanation :

Enthalpy of a reaction (ΔH): It is defined as the energy change that takes place during the chemical processes. It is represented as, ΔH.

If the heat is absorbed during the chemical process then the enthalpy of reaction is positive.

If the heat is released during the chemical process then the enthalpy of reaction is negative.

That means,

When the value of enthalpy of reaction is negative then the heat is released and the reaction will be exothermic reaction.

When the value of enthalpy of reaction is positive then the heat is absorbed and the reaction will be endothermic reaction.