This question has multiple parts and is one question on my OWL V2 Chemistry two
ID: 520953 • Letter: T
Question
This question has multiple parts and is one question on my OWL V2 Chemistry two homework. Any help would be appreciated . I'm learning this for a test upcoming next week.
Consider the reaction
CS2(g)+4H2(g) >< is in equilibrium to form CH4(g)+2H2S(g)
Calculate delta H ,delta S , and delta G at 25°C for this reaction
Reactants/ products delta Hf(kJ/mol) delta S
CS2(g) 116.9 237.9
H2(g) 0 130.6
CH4(g) -74.87 186.1
H2S(g) -20.50 205.6
b. Assume delta H and delta S are constant with respect to a change of temperature. Now calculate delta G at 450°C
c.
Compare the two values of delta G . What can you say about the spontaneity of the reaction at 25°C and at 450°C?Pick one
The reaction will be nonspontaneous at both 25°C and 450°C.
The reaction will be spontaneous at both 25°C and 450°C.
The reaction will be nonspontaneous at 25°C, and it will be spontaneous at 450°C.
The reaction will be spontaneous at 25°C, and it will be nonspontaneous at 450°C.
Explanation / Answer
Calculate delta H ,delta S , and delta G at 25°C for this reaction
a)
dH = Hproducts - Hreactants
dH = (CH4 + 2*H2S) - (CS2 + 4H2)
dH = -74.87 + 2*-20.5 - (116.9 + 4*0) = -232.77 kJ/mol
apply:
dS = Sproducts - Sreactants
dS = (CH4 + 2*H2S) - (CS2 + 4H2)
dS = 186.1 + 2*205.6 - (237.9 + 4*130.6) = -163 J/molK
finally
dG = dH - T*dS = -232.77- 298 * (-163 /1000) = -184.196 kJ/mol
b)
T = 450°C = 723 K
dG = dH - T*dS
dG = dH - T*dS = -232.77- 723 * (-163 /1000) = -114.921 kJ/mol
c)
both are negative, so they are both spontaneous at both T
The reaction will be spontaneous at both 25°C and 450°C.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.