Question

A rigid vessel at constant temperature initially contains 0.600 atm nitrogen gas and 0.600 atm hydrogen gas. if these gases react to form ammonia and the reaction goes to completion, which choice is closest to the final total pressure after the reaction?

Answer 1

The balanced reaction between nitrogen and hydrogen to form ammoinia is as shown.
 N2 + 3H2=2NH3 
Dividing everything by 3
1/3N2 +  H2 = 2/3NH3
All the hydrogen reacts with 1/3 of 0.5 atm of N2
The amount of product is 2/3 × 0.6 atm = 0.4 atm NH3
The unreacted nitrogen is 2/3 × 0.6 atm =0.4 atm Nitrogen
That adds up to 0.8 atm

Answer 2

The final total pressure after the completion of reaction is $\boxed{0.8{\text{ atm}}}$.

Further Explanation:

Stoichiometry:

The amountof species present in the reaction is determined with the help of stoichiometry by the relationship between reactants and products.

Balanced chemical reaction between nitrogen and hydrogen is as follows:

${{\text{N}}_{\text{2}}} + 3{{\text{H}}_2} \to 2{\text{N}}{{\text{H}}_{\text{3}}}$  

This balanced reaction’s stoichiometry clearly indicates that one mole of nitrogen reacts with three moles of hydrogen to produce two moles of ammonia.

Since pressure is directly related to number of moles of gas, pressure required by hydrogen to react with one mole of nitrogen should be three times of pressure of nitrogen.

Therefore pressure of hydrogen can be calculated as follows:

$\begin{aligned}{\text{Pressure of hydrogen}} &= 3\left( {0.600{\text{ atm}}} \right) \\&= 1.8{\text{ atm}} \\\end{aligned}$  

But pressure of hydrogen in the rigid vessel is 0.600 atm only so it behaves as limiting reactant and its amount will govern the amount or quantity of product formed (ammonia).

Since the ratio of pressures of hydrogen and ammonia is 3:2, pressure of ammonia can be calculated as follows:

$\begin{aligned}{\text{Pressure of ammonia}} &= \left( {\frac{2}{3}} \right)\left( {0.600{\text{ atm}}} \right) \\&= 0.4{\text{ atm}} \\\end{aligned}$  

Pressure of unreacted nitrogen can be calculated as follows:

$\begin{aligned}{\text{Pressure of unreacted nitrogen}} &= \left( {\frac{2}{3}} \right)\left( {0.600{\text{ atm}}} \right) \\&= 0.4{\text{ atm}} \\\end{aligned}$  

Therefore total final pressure after the reaction can be calculated as follows:

$\begin{aligned}{\text{Total final pressure}} &= \left( {0.4 + 0.4} \right){\text{ atm}} \\&= {\text{0}}{\text{.8 atm}} \\\end{aligned}$  

Learn more:

1. Calculate the moles of chlorine in 8 moles of carbon tetrachloride: brainly.com/question/3064603
2. Calculate the moles of ions in the solution: brainly.com/question/5950133

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Mole concept

Keywords: stoichiometry, NH3, H2, N2, pressure, hydrogen, nitrogen, ammonia, 0.4 atm, 1.8 atm, 0.600 atm, 3H2, 2NH3, 0.8 atm.