Answer:
7670 joules
Explanation:
Molar heat → 40.6 kJ / mol
1 mol of water occupies 18 g, but we have only 3.4 g. Let's make a rule of three:
18 g of H₂O release 40.6 kJ of heat
Then, 3.4 g will release (3.4 . 40.6) / 18 = 7.67 kJ
If we convert the kJ to J → 7.67 kJ . 1000 J / 1 kJ = 7670 Joules
We can also do this:
If water is already at 100°C, we apply the latent heat (heat that is relased in a change of state)
Q = 2256 J/g . 3.4 g → 7670.4 J