Question

One reaction that produces acid rain is:3 NO2 + H2O -> NO + 2HNO3When 60 grams of water reacts with NO2, 300 grams of HNO3 is produced, what is the percent yield?

Answer 1

The percentage yield is 71.5%

Step-by-step explanation

Given that

The mass of water reacted is 60 grams

The mass of HNO3 produced is 300 grams (Actual yield)

Follow the steps below to find the percentage yield of the reaction

Step 1; Write the balanced equation of the reaction

`\text{ 3NO}_2\text{ + H}_2O\text{ }\rightarrow\text{ NO + 2HNO}_3`

Step 2; Find the number of moles of water using the below formula

`\text{ mole = }\frac{\text{ mass}}{\text{ molar mass}}`

Recall, that the molar mass of H2O is 18.0 g/mol

`\begin{gathered} \text{ mole = }\frac{\text{ 60}}{\text{ 18}} \\ \text{ mole = 3.33 moles} \end{gathered}`

The moles of water is 3.33 moles

Step 3; Find the number of moles of HNO3 using stoichiometry ratio

In the above equation, 1 mole of water reacted to gives 3 moles of HNO3

Let x represents the number of moles of HNO3

`\begin{gathered} \text{ 1 mole H}_2O\rightarrow\text{ 2 moles HNO}_3 \\ \text{ 3.33 moles H}_2O\text{ }\rightarrow\text{ x moles HNO}_3 \\ \text{ Cross multiply} \\ 1\text{ mole H}_2O\text{ }*\text{ x moles HNO}_3\text{ = 2 moles HNO}_3\text{ }*\text{ 3.33 moles H}_2O \\ \text{ Isolate x moles HNO}_3 \\ \text{ x moles HNO}_3\text{ = }\frac{2\text{ moles HNO}_3*3.33moles\cancel{H_2}O}{1moles\cancel{H_2}O} \\ \\ \text{ x moles HNO}_3\text{ = 2 }*\text{ 3.33} \\ \text{ x moles HNO}_3\text{ = 6.66 moles} \end{gathered}`

Step 4; Find the mass of HNO3 using the formula below

`\begin{gathered} \text{ mole = }\frac{\text{ mass}}{\text{ molar mass}} \\ \text{ cross multiply} \\ \text{ mass = mole }*\text{ molar mass} \end{gathered}`

Recall, that the molar mass of HNO3 is 63.01 grams

`\begin{gathered} \text{ mass = 6.66 }*\text{ 63.01} \\ \text{ mass = 419.65 grams} \end{gathered}`

The mass of H2O is 419.65 grams (theoretical yield)

Step 5; Find the percentage yield of the reaction

`\begin{gathered} \text{ Percentage yield = }\frac{\text{ Actual yield }}{\text{ theoretical yield }}*\text{ 100\%} \\ \\ \text{ Percentage yield = }\frac{\text{ 300}}{\text{ 419.65}}*\text{ 100\%} \\ \text{ Percentage yield = 0.715}*\text{ 100\%} \\ \text{ Percentage yield = 71.5\%} \end{gathered}`

Therefore, the percentage yield is 71.5%