Chemical Forums

Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: JimJo on July 22, 2008, 12:19:47 AM

Title: Calculate the amount of heat energy problem...
Post by: JimJo on July 22, 2008, 12:19:47 AM

I really don't know how to start this question, please help me.

The latent heat of vaporization of sulphur dioxide is 25.73KJ/mol and the latent heat of fusion is 8.619 kJ/mol. The boiling point of sulphur dioxide is -10.C and its melting point is -73C. In addition, the specific heat capacity of liquid sulphur dioxide is 0.995J/g.C and for the gas the value is 0.622J/g.C. Calculate the amount of heat energy needed to change 2.500kg of solid SO2, which is at its melting point to a gas at 60.C.

Title: Re: Calculate the amount of heat energy problem...
Post by: Yggdrasil on July 22, 2008, 12:39:15 AM

For these types of problems, it is useful to split it up into different stages:

stage 1: calculate the heat needed to melt the SO₂
stage 2: calculate the heat needed to warm the SO₂ from -73^oC to -10^oC
stage 3: calculate the heat needed to evaporate the SO₂
stage 4: calculate the heat needed to warm the SO₂ to 60^oC

There are a few relevant formulas you will need to know, which you should be able to find in your chemistry text.