Question

Nitrogen dioxide is one of the many oxides of nitrogen (often collectively called "NOx") that are of interest to atmospheric chemistry. It can react with itself to form another form of NOx, dinitrogen tetroxide.A chemical engineer studying this reaction fills a 5.0L flask at 10.°C with 1.9atm of nitrogen dioxide gas. He then raises the temperature considerably, and when the mixture has come to equilibrium determines that it contains 1.1atm of nitrogen dioxide gas.The engineer then adds another 0.95 atm of nitrogen dioxide, and allows the mixture to come to equilibrium again. Calculate the pressure of dinitrogen tetroxide after equilibrium is reached the second time. Round your answer to 2 significant digits.

Answer 1

Answer: The partial pressure of nitrogen dioxide after it is reached the second time is 1.454 atm

Step-by-step explanation:

We are given:

Initial partial pressure of nitrogen dioxide gas = 1.9 atm

First equilibrium partial pressure of nitrogen dioxide gas = 1.1 atm

The chemical equation for the reaction of nitrogen dioxide to dinitrogen tetroxide follows:

`2NO_2\rightleftharpoons N_2O_4`

Initial: 1.9

At eqllm: 1.9-2x x

Evaluating the value of 'x'

`\Rightarrow (1.9-2x)=1.1\\\\x=0.4`

So, equilibrium partial pressure of dinitrogen tetroxide = x = 0.4 atm

The expression of
`K_p` for above equation follows:

`K_p=(p_(N_2O_4))/((p_(NO_2))^2)` ..........(1)

Putting values in above expression, we get:

`K_p=(0.4)/((1.1)^2)\\\\K_p=0.3306`

Now, when more nitrogen dioxide is added, equilibrium is re-established:

Partial pressure of nitrogen dioxide added = 0.95 atm

`2NO_2\rightleftharpoons N_2O_4`

Initial: 2.05 0.4

At eqllm: 2.05-2x 0.4+x

Putting values in expression 1, we get:

`0.3306=((0.4+x))/((2.05-2x)^2)\\\\x=2.51,0.298`

Neglecting the value of x = 2.51 because the equilibrium partial pressure of nitrogen dioxide will become negative, which is not possible.

So, the equilibrium partial pressure of nitrogen dioxide after it is reached the second time = (2.05 - 2x) = [2.05 - 2(0.298)] = 1.454 atm

Hence, the partial pressure of nitrogen dioxide after it is reached the second time is 1.454 atm