Question

How much heat energy in megajoules is needed to convert 7 kilograms of ice at -9c to water at 0c

Answer 1

We can solve this by using the formulas provided to us by calorimetry.

The energy (heat) that is needed to change a given mass of some solid into its liquid form is

E=Lm·m (Where Lm is a specific constant for the material/substance and m is the mass)

Lm for solid water (i.e. ice) is 334 $\frac{Kj}{Kg}$

We can now solve for E

E= 334⋅2 Kj =668Kj

This is the minimum energy required to melt 2 kg of ice. Remember that this energy will in no way change the temperature of the water since every amount of this energy is needed just to melt the solid itself. Even more energy would be needed to increase the end temperature.

Answer 2

The latent heat of fusion of water is 344 j/p.This will take 344x300 or 100200 J to melt the ice. once it melted its at oc