Two Solutions, 250

Two solutions, 250.0 mL of 1.00 M CaCl₂(aq) and 250.0 mL of 1.00 M K₂SO₄(aq) , are added to a calorimeter with a total heat capacity, after the solutions are added, of 1.25 kJ/°C and the temperature decreased by 2.40°C. Determine qrxn per mole of CaSO₄(s) formed in the reaction.

A) +12.0 kJ/mol
B) -12.0 kJ/mol
C) +6.00 kJ/mol
D) -6.00 kJ/mol