Question

The molar heat of fusion of gold is 12.550 kJ mol–1. At its melting point, how much mass of melted gold must solidify to release 235.0 kJ of energy?

Answer 1

1 mole of gold = 197g

12.550 kJ-------------- 197g Au
235.0 kJ--------------------x
x = 3,69g Au

answer: 3,69g Au

Answer 2

Answer;3.67061 kg of gold must be solidified to release 235 kJ of energy.

Explanation:

Molar heat of gold = 12.550 kJ/mol

1 mole of gold releases = 12.550 kJ/mol

Or we can rewrite it as ,1 kJ of energy is given by$[\frac{1}{12.550} mol$

Then 235 kJ of energy will be released by:

$\frac{1}{12.550 kJ}\times 235 kJ=18.72 moles$ of gold

Mass of gold in 18.72 moles = 18.72 mole × 196.08 g/mol =3,670.61 g =3.67061 kg

1 kg = 1000 g

3.67061 kg of gold must be solidified to release 235 kJ of energy.