Question

The equilibrium constant, K, for the following reaction is 10.5 at 350 K.

2CH2Cl2(g) CH4(g) + CCl4(g)

An equilibrium mixture of the three gases in a 1.00 L flask at 350 K contains 5.09E-2 M CH2Cl2, 0.165 M CH4 and 0.165 M CCl4. What will be the concentrations of the three gases once equilibrium has been reestablished, if 3.82E-2 mol of CH2Cl2(g) is added to the flask?

[CH2Cl2]

=

M

[CH4]

=

M

[CCl4]

=

M

The equilibrium constant, K, for the following reaction is 1.29E-2 at 600 K.

COCl2(g) CO(g) + Cl2(g)

An equilibrium mixture of the three gases in a 1.00 L flask at 600 K contains 0.192 M COCl2, 4.98E-2 M CO and 4.98E-2 M Cl2. What will be the concentrations of the three gases once equilibrium has been reestablished, if 2.93E-2 mol of Cl2(g) is added to the flask?

[COCl2]

=

M

[CO]

=

M

[Cl2]

=

M

Answer 1

2CH2Cl2(g) <---------------> CH4(g)   +   CCl4(g)      Kc = 10.5

   0.0509                                0.165     0.165    ------------ equilibrium

0.0509 + 2x                           0.165 - x      0.165 - x     ------------- equilibrium re-establish

2x = 0.0382 is given

x= 0.0191

equilibrium concentrations after reestablish

[CH2Cl2] = 0.0509 + 2x = 0.0891 M

[CH4] = 0.165-x = 0.146M

[CCl4] = 0.165-x = 0.146 M

COCl2(g) <------------------------->CO(g)      +     Cl2(g)

0.192                                        0.0498             0.0498 ----------------> equibrium concentration

0.192-x                                   0.0498+x           0.0498+x ---------------> after equibrium reestablishment

but x = 0.0293 is given

after equibrium reestablishment concentrations:

[COCl2] = 0.192-x = 0.163 M

[CO] = 0.0498+x   =0.0791M

[Cl2] = 0.0498+x   =0.0791M