The standard enthalpy of formation of CaSO 4 (s) at 25 ◦ C is − 1432 . 7 kJ mol − 1 .The equation that describes this formation reaction is: (A) CaSO 4 (s) −−→ Ca(s) S(s) 2 O 2 (g) (B) Ca(s) S(s) 2 O 2 (g) −−→ CaSO 4 (s) (C) Ca 2 (aq) SO 2 − 4 (aq) −−→ CaSO 4 (s) (D) CaSO 4 (s) −−→ Ca(s) S(s) 4 O(g) (E) Ca(s) S(s) 4 O(g) −−→ CaSO 4 (s)