Question

How much energy does it take to convert .500 kg of ice at -20°C to steam at 250°C.

Specific heat capacities:
Ice: 2.03 J/g °C
Water: 4.2 J/g°C
Steam: 2.0 J/g C

Answer 1

Use the specific heat equation for each one:

Q = mCT

m is mass
T is change in temp
C is spec heat

You will not only have to calculate three different specific heats, but also do the heat of vaporization and heat of fusion.

Heat of vaporization is 3.33 * 10^5 J/Kg

Heat of Fusion is 2.26 * 10^6 J/Kg

You’ll want to make sure all your units match. So change all Kg to g (or g to Kg)


-20 to 0 = mC(Ice)T

Melt ice (fusion) = m(heat of fusion)

0 to 100 = mC(Water)T

Boil (Vaporization) = m(heat of vaporization)

100 to 250 = mC(Steam)T


Then add each one together