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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: diablo on November 01, 2009, 01:17:37 PM

Title: enthalpy change
Post by: diablo on November 01, 2009, 01:17:37 PM

Hi folks, i can't solve this:

calculate the enthalpy change (dH) for 1mol ideal gas, when it changes from 27°C/1atm to 327°C/17atm.
The heat capacity is given as C_p,m = 20,9+0,042T/K (Unit = JK^-1mol^-1)
Solution: dH = 1,19*10⁴J

I tried to find the right formular:

C_p,m = a +bT+c/T² (from atkins)

and because there is no c/T² Term, i changed it into:

dH = Integral(from T1 to T2) of: (a +bT)
--> dH= a(T1-T2)+0,5*b*((T2)² - (T1)²)

now if i put the values into the formular i dont get the right value...

can you please help me?