Chem390_solution_5 - Solution to PS 5 Problem 1(a Standard molar entropy change is given by the total molar entropy for the products minus the

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

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

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

Unformatted text preview: Solution to PS 5 Problem 1 (a) Standard molar entropy change is given by the total molar entropy for the products minus the entropy for the reactants. In[53]:= S HBRg = 198.7 J ê mol ê K; S Br2g = 245.5 J ê mol ê K; S H2g = 130.7 J ê mol ê K; S HBRg − 0.5 ∗ S Br2g − 0.5 ∗ S H2g Out[56]= 10.6 J K mol (b) The entropy of Br2(g) is larger than Br2(l) at the same T and p by the amount of D vap H/ T vap . The large entropy increase in this case is consistentwith the loss of condensed material H Br2 H l LL to produce gaseous HBr. In[57]:= S Br2l = 152.2 J ê mol ê K; S HBRg − 0.5 ∗ S Br2l − 0.5 ∗ S H2g Out[58]= 57.25 J K mol (c) D S(p,T)= D S(1bar,T)+ Ÿ 1 bar p I ∑ p ' S M T „ p ' =D S(1bar,T)- Ÿ 1 bar p H ∑ T V L p ' „ p '. Assuming ideal gas, the second term becomes - Ÿ 1 bar p H R ê p ' L „ p ' = - Rln H p ê 1 bar L . At 5 bar, the entropy increase is the same for the product H total 1 mole L and the reactants H total 1 mole of gas L . Hence the molar entropy change for 5 bar is the same as at 1 bar. Answer : 10.6 J ê K ê mol Problem 2 In[121]:= S trans = Log B 2 π M kB T h 2 3 ê 2 R T 1 bar Æ 5 ê 2 ë NA F ê . constJSI S rot = Log @ T Æ ê H σ Θ rot LD ; S vib = − Log A 1 − Æ −Θ vib ë T E + Θ vib ê T Æ Θ vib ë T − 1 ; S el = Log @ gel D ; (1) The formula above are given in units of R. Below all entropy values are given in units of R.units of R....
View Full Document

This note was uploaded on 05/04/2009 for the course CHEM 3900 taught by Professor Park during the Spring '08 term at Cornell University (Engineering School).

Page1 / 5

Chem390_solution_5 - Solution to PS 5 Problem 1(a Standard molar entropy change is given by the total molar entropy for the products minus the

This preview shows document pages 1 - 3. Sign up to view the full document.

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