If 24.7 G Of NO And 13.8 G Of $O_2$ Are Used To Form $NO_2$, How Many Moles Of Excess Reactant Will Be Left Over?$2 NO(g) + O_2(g) \rightarrow 2 NO_2(g$\]

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If 24.7 g of NO and 13.8 g of O2 are used to form NO2, how many moles of excess reactant will be left over?

Understanding the Chemical Reaction

The given chemical reaction is: 2 NO(g) + O2(g) → 2 NO2(g)

This reaction involves the combination of nitrogen monoxide (NO) and oxygen (O2) to form nitrogen dioxide (NO2). The balanced equation indicates that 2 moles of NO react with 1 mole of O2 to produce 2 moles of NO2.

Calculating the Number of Moles of NO and O2

To determine the number of moles of excess reactant left over, we need to calculate the number of moles of NO and O2 used in the reaction.

The molar mass of NO is 30.01 g/mol (14.01 g/mol for N and 16.00 g/mol for O).

The number of moles of NO used is: 24.7 g / 30.01 g/mol = 0.823 mol

The molar mass of O2 is 32.00 g/mol (16.00 g/mol for each O atom).

The number of moles of O2 used is: 13.8 g / 32.00 g/mol = 0.431 mol

Determining the Limiting Reactant

To determine the limiting reactant, we need to compare the mole ratio of NO to O2 in the reaction with the mole ratio of NO to O2 used.

The balanced equation indicates that 2 moles of NO react with 1 mole of O2. Therefore, the mole ratio of NO to O2 in the reaction is 2:1.

The mole ratio of NO to O2 used is 0.823 mol : 0.431 mol, which is approximately 1.9:1.

Since the mole ratio of NO to O2 used is greater than the mole ratio in the reaction, O2 is the limiting reactant.

Calculating the Number of Moles of Excess Reactant

Since O2 is the limiting reactant, the amount of NO used will be in excess.

The number of moles of excess NO is: 0.823 mol - 0.431 mol (since 0.431 mol of O2 is used) = 0.392 mol

Therefore, 0.392 mol of NO will be left over as excess reactant.

Conclusion

In this problem, we calculated the number of moles of excess reactant left over when 24.7 g of NO and 13.8 g of O2 are used to form NO2. We determined that O2 is the limiting reactant and that 0.392 mol of NO will be left over as excess reactant.

Calculating the Mass of Excess Reactant

To calculate the mass of excess reactant, we need to multiply the number of moles of excess reactant by the molar mass of the excess reactant.

The molar mass of NO is 30.01 g/mol.

The mass of excess NO is: 0.392 mol x 30.01 g/mol = 11.76 g

Therefore, 11.76 g of NO will be left over as excess reactant.

Calculating the Percentage of Excess Reactant

To calculate the percentage of excess reactant, we need to divide the mass of excess reactant by the total mass of reactants used and multiply by 100.

The total mass of reactants used is: 24.7 g (NO) + 13.8 g (O2) = 38.5 g

The percentage of excess reactant is: (11.76 g / 38.5 g) x 100 = 30.5%

Therefore, 30.5% of the reactants used will be left over as excess reactant.

Conclusion

In this problem, we calculated the number of moles of excess reactant left over when 24.7 g of NO and 13.8 g of O2 are used to form NO2. We determined that O2 is the limiting reactant and that 0.392 mol of NO will be left over as excess reactant. We also calculated the mass and percentage of excess reactant.
Q&A: Understanding the Chemical Reaction and Excess Reactant

Q: What is the chemical reaction between NO and O2 to form NO2?

A: The chemical reaction between NO and O2 to form NO2 is: 2 NO(g) + O2(g) → 2 NO2(g)

Q: What is the limiting reactant in this reaction?

A: In this reaction, O2 is the limiting reactant. This means that the amount of O2 used is less than the amount required to react with all the NO.

Q: How do you calculate the number of moles of excess reactant?

A: To calculate the number of moles of excess reactant, you need to determine the limiting reactant and then subtract the amount of the limiting reactant used from the amount of the other reactant used.

Q: What is the molar mass of NO and O2?

A: The molar mass of NO is 30.01 g/mol and the molar mass of O2 is 32.00 g/mol.

Q: How do you calculate the mass of excess reactant?

A: To calculate the mass of excess reactant, you need to multiply the number of moles of excess reactant by the molar mass of the excess reactant.

Q: What is the percentage of excess reactant?

A: The percentage of excess reactant is calculated by dividing the mass of excess reactant by the total mass of reactants used and multiplying by 100.

Q: Why is it important to determine the limiting reactant and excess reactant?

A: Determining the limiting reactant and excess reactant is important because it helps you understand the reaction and predict the amount of product formed. It also helps you identify the reactant that is in excess and can be recovered or reused.

Q: Can you give an example of a real-world application of determining the limiting reactant and excess reactant?

A: Yes, a real-world application of determining the limiting reactant and excess reactant is in the production of fertilizers. In the production of fertilizers, the limiting reactant and excess reactant are used to determine the amount of product formed and the amount of reactant that can be recovered or reused.

Q: How do you determine the limiting reactant and excess reactant in a chemical reaction?

A: To determine the limiting reactant and excess reactant in a chemical reaction, you need to compare the mole ratio of the reactants in the reaction with the mole ratio of the reactants used. The reactant with the lower mole ratio is the limiting reactant, and the reactant with the higher mole ratio is the excess reactant.

Q: What are some common mistakes to avoid when determining the limiting reactant and excess reactant?

A: Some common mistakes to avoid when determining the limiting reactant and excess reactant include:

  • Not balancing the chemical equation
  • Not calculating the mole ratio of the reactants
  • Not comparing the mole ratio of the reactants in the reaction with the mole ratio of the reactants used
  • Not considering the stoichiometry of the reaction

Q: How do you calculate the yield of a chemical reaction?

A: To calculate the yield of a chemical reaction, you need to determine the amount of product formed and the amount of reactant used. The yield is calculated by dividing the amount of product formed by the amount of reactant used and multiplying by 100.

Q: What is the difference between yield and percentage yield?

A: The difference between yield and percentage yield is that yield is the amount of product formed, while percentage yield is the percentage of product formed relative to the amount of reactant used.