Thanks 3 Calculate the final temperature of a sample of argo

3. Calculate the final temperature of a sample of argon gas of mass 12.0 g after it is expanded reversibly and adiabatically from 1.00 L at 0.00 °C to 3.00 L. Assume that C,- 2.500R. 4. Find the standard internal energy of formation, , of liquid methyl acetate at 298 K given the standard enthalpy of formation AH442kJ mol. Remember that AF1\" = Uo +A(PV). Assume that all gases involved in the formation reaction are ideal.

Solution

3)Value of gamaa(Y) = Cp/Cv = 2.5R/1.5R = 1.67 (Here Y is assume to be gamaa) .

PV^Y = C

TV^Y-1 = C ; 273(1)^Y-1 = T(3)^Y-1 = T(2.09) ; T = 130.62K

4) 3C(graph)+3H2 (g)+O2 (g) C3H6O2 (l)

Ng = [products] – [reactants] = [0] – [ 4 mol] = -4 mol

H = U + Ng RT
(1 mol)(-442.0 kJ mol-1) = rU + (-4 mol)(8.314 J K-1 mol-1)(1 kJ/1000 J)(298.2 K) fU° = rU = -442.0 kJ + 9.92 kJ = -432.1 kJ

So Value of U = -432.1 kJ