[nlb149]

The molar heat capacity CP, m of SO2(g) is described by the following equation over the range 300 K < T < 1700 K:
Cp,m /R = 3.093 + 6.967 x 10^-3 T/K - 45.81 x 10^-7 T^2/K^2 + 1.035 x 10^-9 T^3/K^3

In this equation, T is the absolute temperature in Kelvin. Theratios ensure that CP, m has the correct units. Assuming ideal gas behavior, calculate q, w, delta U, and delta H if 2.25 mol of SO2(g) is heated from 45.5° to 1285°C at a constant pressure of 1 bar. Explain the sign of w.


okay so I know that q = delta H = nR integral of Cp dT from T1 to T2.  I did this and got 1.45 x 10^5 Joules for delta H which according to the back of the book is right.  I'm having trouble taking that and finding delta U or w.  Any ideas?

[Yggdrasil]

Do you know the definition of ΔH (that relates it to ΔU)?  What equations do you know for w?

[nlb149]

 :delta: H =  :delta: U +  :delta:(PV) and U = q + w are the only ones I know. 

[Yggdrasil]

:delta: H =  :delta: U +  :delta:(PV) and U = q + w are the only ones I know. 

Those are the ones to use (also, you need to use the ideal gas law).