Ammonia (NH3) reacts with oxygen to form nitric oxide (NO) and water vapor: 4NH3 + 502 4NO + 6H2O b) When 20.0 g NH3 and 50.0 g O2 are allowed to react, which is the limiting reagent? Which reactant is left over and how much left over at the end of reaction? Ans: 2.94 g c) What is the theoretical yield of NO if 20.0 g NH3 and 50.0 g O2 are allowed to react? Ans: 35.29 g d) What is the theoretical yield of H20 if 20.0 g NH3 and 50.0 g O2 are allowed to react? Ans: 31.74 g

Respuesta :

Answer: a) . Ammonia is the limiting reagent

b. Oxygen is left over and 0.1375 g of oxygen is left over.

c. The theoretical yield of [tex]NO[/tex] is 35.29 g.

d. The theoretical yield of [tex]H_2O[/tex] is 31.74 g.

Explanation:

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]  

For [tex]NH_3[/tex]

Given mass of ammonia = 20.0 g

Molar mass of ammonia = 17.031 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of ammonia}=\frac{20.0g}{17.031g/mol}=1.17mol[/tex]

For [tex]O_2[/tex]

Given mass of oxygen gas = 50.0 g

Molar mass of oxygen gas = 32 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of oxygen gas}=\frac{50.0g}{32g/mol}=1.6mol[/tex]

The chemical equation for the reaction is

[tex]4NH_3+5O_2\rightarrow 4NO+6H_2O[/tex]

By Stoichiometry of the reaction:

4 moles of ammonia reacts with = 5 moles of oxygen

So 1.17 moles of ammonia will react with = [tex]\frac{5}{4}\times 1.17=1.4625mol[/tex] of oxygen

As, given amount of oxygen is more than the required amount. So, it is considered as an excess reagent and (1.6-1.4625)= 0.1375 g of oxygen is left unreacted.

Thus ammonia is considered as a limiting reagent because it limits the formation of product.

1. By Stoichiometry of the reaction:

4 moles of ammonia produces = 4 moles of [tex]NO[/tex]

1.17 moles of ammonia will produce = [tex]\frac{4}{4}\times 1.17=1.17moles[/tex] of [tex]NO[/tex]

Mass of [tex]NO=moles\times {\text{Molar Mass}}=1.17\times 30=35.29g[/tex]

Thus Theoretical yield of [tex]NO[/tex] is 35.29 grams.

2. By Stoichiometry of the reaction:

4 moles of ammonia produces = 6 moles of [tex]H_2O[/tex]

1.2 moles of ammonia will produce = [tex]\frac{6}{4}\times 1.2=1.8moles[/tex] of [tex]H_2O[/tex]

Mass of [tex]H_2O=moles\times {\text{Molar Mass}}=1.8\times 18.015=31.74g[/tex]  [tex]H_2O[/tex]

Thus Theoretical yield of [tex]H_2O[/tex] is 31.74 grams.