A125 ml sample of 1.33 m hcl and 225 ml of 0.625 m naoh, both initially at 24.4 c are allowed to react in a calorimeter. what is the final temperature in the calorimeter? (heat of rxn=-57.2 kj) (ans: 29.9 c)

answer; i believe that the correct answer is (a) potassium(k)

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

the volume increases