Question

CaCl2(aq)+Na3PO4(aq) -----------> Ca3(PO4)2(s) +NaCl(aq)4) If the “H” for this reaction is -45.5 kJ/mol, is the reaction endo- or exothermic?

Exothermic

Answer 1

Yes, the - sign tells you it is exothermic. Note that the equation you wrote should be 3NaCl.