Tuesday
May 3, 2016

# Homework Help: Chemistry

Posted by Garret on Sunday, September 30, 2007 at 9:21am.

How many kcal of heat energy are required or released when 1.73 moles of butanol , C4H9OH, is warmed from -175.8 degrees F to 360.9 degrees F? The following information concerning butanol applies:
normal melting point: 12.5 degrees C
normal boiling point: 162.8 degrees C
Cp (s) = 2.91 J/g degrees C
Cp (l) = 3.27 J/g degrees C
Cp (g) = 2.36 J/g degrees C

Show the diagram that applies to this substance, including mp, bp, delta Hc, delta Hv, phases involved, starting point and stopping point.

Then calculate the heats needed for for each step and the final heat required or released. State whether required or released in answer.

Ok, I know how to do the staircase diagram with the phases at each level, but I'm not sure how to calculate the heat needed for each step.
• Chemistry - bobpursley, Sunday, September 30, 2007 at 9:29am

when it is solid, liquid, or gas, the heat involved is m*c*deltaTemp

At the transition pointss, melting, and again at boiling, there is a heat

L*mass where L, the latent heat per mass, is either Lv (vaporiation heat/gram) or Lf(melting heat/gram)

We will be happy to critique your work.