Calculating Heat Required to Change 1.0 kg of Ice to Steam

[Mr. Goosemahn]

Homework Statement

How much heat in kcal is required to change 1.0 kg of ice, originally at -30 degrees C, into steam at 120 degrees C? Assume 1.0 atm of pressure. (Please use the following values for the constants needed in the problem: Latent heat of fusion=79.7 kcal/kg; Specific heat of ice=0.5 kcal/kg/K; Latent heat of vaporization=539 kcal/kg; Specific heat of water 1.0 kcal/kg/K; Specific heat of steam=0.480 kcal/kg)

Homework Equations

Q_melt=mL_fusion
Q_freeze=-mL_fusion
Q_vaporization=mL_vaporization
Q_condensation=-mL_vaporization

The Attempt at a Solution

Quite honestly, I don't even know how to start. I don't see how the 1.0 atm of pressure is involved in the equations.

Could somebody just tell me how to start this off and I'll take it from there.

I've been reading from my book but it's not clear.

I had originally tried to use the equation Q=cmT, with the values plugged in as Q=4186*1*150, giving me 627.9 kilocalories, but this is incorrect.

 

[rl.bhat]

Divide the problen into five sections.
i) Q1 = m*ci*ΔT----(1)
ii) Q2 = m*Lfreeze -----(2)
similarly right the remaining equations and find the total Q..