The G at nonstandard conditions can be found using the equation G=G°+RTlnQ Refer
ID: 1015887 • Letter: T
Question
The G at nonstandard conditions can be found using the equation
G=G°+RTlnQ
Referring to the same reaction
Fe2O3 (s) + 3C (graphite) --> 2 Fe (s) + 3CO (g)
a) show the formula setup for Q (how it depends on concentrations and/or pressures). It is conventional in thermodynamics to use pressure for gases and molarities for aqueous solutions. When set up that way, Q may be a "hybrid" of both pressures and molarities.
b)Calculate the value of G at T = 1000 K and the P of CO = .1 atm
c) calculate the value of G at T= 1000 K and the P of CO=10 atm
d) as we see now, formation of a gas at high pressure has different G from formation of the same gas at low pressure. Explain how the results of parts (b) and (c) make sense using "freedom of molecular motion".
Please explain, Thank you.
Explanation / Answer
Q = [CO]3 since rest of the elements are solids
K= Equilibrium constant = [CO]3
for CO= 0.1 atm, K= (0.1)3= 0.001, deltaG= -RTlnK= -8.314*1000*ln(0.001)= 57431 Joules/mole
for CO= 10 atm K= (10)3= 1000, deltaG= -8.314*1000* 1000 =-8314000 joules/mole
so the process is spontaneous at 10 atm
As pressrue is increased, the entropy decreased, entropy decreases and freedom of molecules is restricted.