How much heat is released when 200 grams of sodium hydroxide dissolve in water?

Question

a) -210 kj b)210kj c)-23kj d)223kj

Can you explain, Please?

Answer 1

The enthalpy of solution of NaOH is - 44.45 kJ / mol

The molecular weight of NaOH is 39.9971 g/mol

(200 g) / (39.9971 g/mol) ≈ 5.000363 moles

(5.000363 moles)(- 44.45 kJ / mol) ≈ - 222.2661 kJ

The - sign indicates that heat is released, so the heat released is 222.2661 kJ, which is closest to your choice d).