Question

Nitric oxide, an important pollutant in air, is formed from the elements nitrogen and oxygen at high temperatures, such as those obtained when gasoline burns in an automobile engine. At 2000 oC, the K for the following reaction is 0.01.
N2 (g) + O2 (g) « 2 NO (g)

Predict the direction in which the system will move to reach equilibrium at 2000 oC if 0.4 moles of nitrogen and 0.1 moles of oxygen and 0.08 moles of NO are placed in a 1.0 L container. Hint: Calculate Q.

Answer 1

Answer:

Q is 0.5 and K is 0.01, therefore K is less than Q.

the system will proceed in the reverse direction, thereby converting products into reactants. converting Nitric oxide to form oxygen and nitrogen.

Explanation:

Given,

N2 (g) + O2 (g) « 2 NO (g)

K = 0.01

heated temperature = 2000 ⁰C

N2 moles =0.4

O2 moles =0.1

2NO moles = 0.08

Volume of container = 1L

Q is the reaction quotient  of the equilibrium equation. it is use to determined which direction the system will move to by comparing it with the K value.

Q can be calculated by multiplication of mass of reactant divide by mass of product

Q =$\frac{ [N2] *[O2}{2NO}$

the mass of the chemicals are in mole, there is need to convert them to moles/litre

therefore,

for N₂ : 0.4 mole per 1L container = 0.4 mol/L = 0.4M

for O₂ : 0.1 mole per 1L container = 0.1 mol/L = 0.1M

for 2NO : 0.08mole per 1L container = 0.08 mol/L = 0.08M

Q =$\frac{ [N2] *[O2}{2NO}$ = (0.4*0.1)/0.08 = 0.5

finally, we are going to compare the value of Q with K

Note that:

if K>Q , the reaction will proceed forward, converting reactants into product.

if K<Q , the reaction will proceed backward, converting products into reactants.

if K=Q , the system of reaction is already in equilibrium.

since, Q is 0.5 and K is 0.01, therefore K is less than Q.

the system will proceed in the reverse direction, thereby converting products into reactants. converting Nitric oxide to form oxygen and nitrogen.