Question

The symbol ∆hf° stands for the _____. heat of reaction for a chemical reaction specific heat of a substance standard heat of formation for a compound heat capacity of a substance

Answer 1

ΔHfo stands for standard heat of formation for a compound.

Heat of formation of compound is mathematically expressed as,
∑Hproducts - ∑Hreactants

If value of ΔHfo is negative, it suggest that is exothermic reaction. If ΔHfo is positive, it suggest that it is endothermic reaction.