Question

If a mixture of reactants and products contains 0.035 M H20, 0.050 M CH4, 0.15 MCO, and 0.20 M H2. For the reaction: H2O (g) + CH4 (g) = CO (g) + 3 H2(g) Kc = 4.7 at 1400 K. In which direction does the reaction proceed to reach equilibrium? What is the value of Kp? 9. Write the equilibrium constant expression Kc for: C2H4OH (aq) + 0, (aq)=CH-COH (aq) + H2O (0)

Answer 1

Answer : The reaction must shift to the product (right) to be in equilibrium.

The value of $K_p$ is $6.2\times 10^{4}$

Explanation :

Reaction quotient (Q) : It is defined as the measurement of the relative amounts of products and reactants present during a reaction at a particular time.

The given balanced chemical reaction is,

$H_2O(g)+CH_4(g)\rightarrow CO(g)+3H_2(g)$

The expression for reaction quotient will be :

$Q=\frac{[CO][H_2]^3}{[H_2O][CH_4]}$

In this expression, only gaseous or aqueous states are includes and pure liquid or solid states are omitted.

Now put all the given values in this expression, we get

$Q=\frac{(0.15)\times (0.20)^3}{(0.035)\times (0.050)}=0.686$

The given equilibrium constant value is, $K_c=4.7$

Equilibrium constant : It is defined as the equilibrium constant. It is defined as the ratio of concentration of products to the concentration of reactants.

There are 3 conditions:

When $Q>K_c$ that means product > reactant. So, the reaction is reactant favored.

When $Q<K_c$ that means reactant > product. So, the reaction is product favored.

When $Q=K_c$ that means product = reactant. So, the reaction is in equilibrium.

From the above we conclude that, the $Q<K_c$ that means product < reactant. So, the reaction is product favored that means reaction must shift to the product (right) to be in equilibrium.

Now we have to calculate the value of $K_p$

The relation between $K_p$ and $K_c$ are :

$K_p=K_c\times (RT)^{\Delta n}$

where,

$K_p$ = equilibrium constant at constant pressure = ?

$K_c$ = equilibrium concentration constant = 4.7

R = gas constant = 0.0821 L⋅atm/(K⋅mol)

T = temperature = 1400 K

$\Delta n$ = change in the number of moles of gas = [(3 + 1) - (1 + 1)] = 2

Now put all the given values in the above relation, we get:

$K_p=4.7\times (0.0821L.atm/K.mol\times 1400K)^{2}$

$K_p=6.2\times 10^{4}$

Thus, the value of $K_p$ is $6.2\times 10^{4}$