Question

Consider the decomposition of a metal oxide to its elements, where M represents a generic metal Find: -Grxn -K -P(o2) M2O3(s)<----> 2M(s) +3/2O2 (g) M2O3= -6.70 M(s)=0 02=0 Please explain

Answer 1

The given reaction is follows:

M2O3(s)<----> 2M(s) +3/2O2 (g)

And given that M2O3= -6.70 M(s)=0 02=0

Calculate the dG0 as follows:

dG0 = dG0 (products) - dG0 (reactants)

= 2 * dG0 (M)+ 3/2 * dG0 (O2) - * dG0 (M2O2)

= 2*0+3/2*0- (-6.70)

=6.70 KJ/ mole

T = temperature, 298K

R= 8.314 J/ mol .K

K = exp (-dG0/RT)

= exp - 6.70 *1000J/ mole/8.314 J/ mol .K *298K

=exp-2.70

= 0.0672

Now calculate P(o2) as follows:

K = p (O2)^3/2

0.0672 = p (O2) ^3/2

Now taking log

log 0.0672 = 3/2 log p (O2)

-1.173*2/3= log p (O2)

p (o2)=10^-0.782

= 0.165 atm