[xeadgbex]

This is my first time using this forum. Hopefully I can get some help on this one here :]

Phase Change question: How much heat is needed to convert 66.5g C2Cl3F3 from a liquid at 11.15C to a gas at 88C.
Boiling Point: 47.6C
Specific Heat (l): .91J/gK
Specific Heat (g): .67J/gK
Heat of Vapor: 27.49kJ/mol
I calculated 66.5g C2Cl3F3 as being .738 mol

MY ANSWER:
Step 1) q=m x s x deltaT
66.5g x .91 x (320.75k - 284.3k) = 2205.77

Step 2) q=Hvap x mol
27.49 x 66.5g x (1 mol/90g) = 20.29

Step 3) m x s x deltaT
66.5g x .67 x (361.15k - 320.75k) = 1800.02

Add all the answers up and I have 4026.08 which is incorrect. I've been stuck on this for a while..

Any assistance in much appreciated.

[Borek]

I calculated 66.5g C2Cl3F3 as being .738 mol

Check.

[xeadgbex]

This is my first time using this forum. Hopefully I can get some help on this one here :]

Phase Change question: How much heat is needed to convert 66.5g C2Cl3F3 from a liquid at 11.15C to a gas at 88C.
Boiling Point: 47.6C
Specific Heat (l): .91J/gK
Specific Heat (g): .67J/gK
Heat of Vapor: 27.49kJ/mol
I calculated 66.5g C2Cl3F3 as being .355

MY ANSWER:
Step 1) q=m x s x deltaT
66.5g x .91 x (320.75k - 284.3k) = 2205.77

Step 2) q=Hvap x mol
27.49 x 66.5g x (1 mol/187.37g) = 9.76

Step 3) m x s x deltaT
66.5g x .67 x (361.15k - 320.75k) = 1800.02

Add all the answers up and I have 4015.55 which is incorrect. I've been stuck on this for a while..

Any assistance in much appreciated.

I've corrected that error in the quote above. I'm still getting an incorrect answer of 4015.55.. :[

[xeadgbex]

Never mind i've found out what I did wrong. Eq#2's answer was in KJ while one and three were in J. I have to move the dec on EQ 2 to get the correct answer.

Thank you.

[Borek]

I was about to post kJ vs J hint