exam2_sol - 1. Calculate H for the reaction C(diamond)...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1. Calculate H for the reaction C(diamond) C(graphite) at the following conditions: A. T=25 0 C, P = 1bar ( ) ( ) 1895 / ff H H gr H diamond J mol ∆= = B. T = 125 0 C, P = 1bar (125 ) (25 ) ( ( ) ( ))(125 25 ) 1653.6 / pp H C H C C graphite C diamond C C J mol + = C. T = 25 0 C, P = 2000 bar This is very similar to your problem 3B from HW3: 00 0 0 () ( ) ( ) ( ) ()( ) ( ) 1512 / gr diamond gr gr diamond diamond gr diamond HP H P H P H P V P P MM HP VP P H P P P Jm o l ρρ +− −− = + =− The thermodynamic properties of graphite and diamond at T = 25 0 C and P = 1 bar are given in the table below. Assume that the densities and the heat capacities of both materials are constant H f , J/mol p C , J K -1 mol -1 density, g/cm 3 C(graphite) 0 8.527 2.25 C(diamond) 1895 6.113 3.51
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2. 100 grams of ethanol (C 2 H 5 OH) are mixed with 100 grams of methanol (CH 3 OH) at T = 10 0 C and form an ideal solution. This is problem 2 from HW 4. A. Calculate G as a result of mixing 00 0 0 11 2 2 1 1 1 2 2 2 1 1 2 2 () ( l n ) ( l n ) ( l n l n ) G n n n n n RT x n RT x nn R T n x n x µµ µ ∆= + + = + + + −+ = + Here n 1 = 100g/46(g/mol)=2.174 mol n 2 = 100g/32(g/mol) = 3.125 mol x 1 = n 1 /(n 1 +n 2 ) = 0.41, x 2 = 1-x 1 = 0.59 so that G = -8440 J B. Calculate A See the solution of the homework problem: G= A = -8440J C. What is the change of the entropy of the surroundings as a result of this process? / surr SH T As we discussed in the class, H=0 in the case where ideal solution is formed, so 0 surr S
Background image of page 2
3.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 5

exam2_sol - 1. Calculate H for the reaction C(diamond)...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online