Question

Which of the following equations can be used to determine the change in enthalpy of a system? A. `DeltaH_"reaction"=DeltaH_"products"×DeltaH_"reactants"` B. `DeltaH_"reaction"=DeltaH_"products"÷DeltaH_"reactants"` C. `DeltaH_"reaction"= DeltaH_"products"+DeltaH_"reactants"` D. `DeltaH_"reaction" = DeltaH_"products"−DeltaH_"reactants"`

Answer 1

Answer: The correct answer is Option D.

Explanation:

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. It is represented as $\Delta H^o$

The equation used to calculate enthalpy change is of a reaction is:  

$\Delta H^o_{rxn}=\sum [n\times \Delta H^o_f_{(product)}]-\sum [n\times \Delta H^o_f_{(reactant)}]$

Hence, the correct answer is Option D.