Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

f ? G ?=? R T ln K Under conditions other than standard state, the following equ

ID: 852624 • Letter: F

Question

f

?G?=?RTlnK

Under conditions other than standard state, the following equation applies:

?G=?G?+RTlnQ

Part A

C2H2(g)+2H2(g)?C2H6(g)

The equilibrium constant of a system, K, can be related to the standard free energy change, ?G, using the following equation:

?G?=?RTlnK

where T is a specified temperature in kelvins (usually 298 K) and R is equal to 8.314 J/(K?mol).

Under conditions other than standard state, the following equation applies:

?G=?G?+RTlnQ

In this equation, Q is the reaction quotient and is defined the same manner as K except that the concentrations or pressures used are not necessarily the equilibrium values.

Part A

Acetylene, C2H2, can be converted to ethane, C2H6, by a process known as hydrogenation. The reaction is

C2H2(g)+2H2(g)?C2H6(g)

Given the following data at standard conditions (all pressures equal to 1 atm and the common reference temperature 298 K), what is the value of Kp for this reaction? Substance ?G?f
(kJ/mol) C2H2(g) 209.2 H2(g) 0 C2H6(g) ?32.89

Explanation / Answer

Assuming a temperature of 298 K,

K = e^(242,090 J*(1/298K)*(1/8.314))

K = 2.7 X10^42