Answer:
CaF₂+H₂SO₄ → CaSO₄+2HF ΔH = +157.7KJ
Explanation:
Energy changes in chemical reactions is one of the most important issues in thermodynamics especially the enthalpy of reaction (ΔHrxn)
- (ΔHrxn) can be defined as the difference between the total enthalpy of the products and the total enthalpy of the reactants of a certain reaction.
- If ΔH<0 for an exothermic reaction (i.e. heat flows from a system to its surroundings) or in other words, the enthalpy of the products is less than the enthalpy of the reactants
- While, ΔH>0 for an endothermic reaction (i.e. heat flows from the surroundings to a system) that means the enthalpy of the products is greater than the enthalpy of the reactants.
CaF₂+H₂SO₄+157.7KJ → CaSO₄+2HF
- heat flows from the surroundings to a system and so ΔH>0
which can be expressed in alternate form as following
CaF₂+H₂SO₄ → CaSO₄+2HF ΔH = +157.7KJ
