How many moles of nitric acid are produced starting from 5.00 moles of NO2(g) and 2.00 moles of water?

Question 29 options:

4.00 mol


1.67 mol


7.50 mol


3.33 mol


10.0 mol

To determine how many moles of nitric acid are produced, we need to find the limiting reactant between NO2(g) and water. The balanced chemical equation for the reaction is:

3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g)

The coefficients in the balanced equation indicate the mole ratio between reactants and products. Therefore, we need to calculate the moles of nitric acid produced from both reactants and see which one produces the lesser amount.

From the balanced equation, we can see that the mole ratio between NO2 and HNO3 is 3:2, meaning that for every 3 moles of NO2, 2 moles of HNO3 are produced.

Using this ratio, we can calculate the moles of HNO3 produced from 5 moles of NO2:

5 moles NO2 * (2 moles HNO3 / 3 moles NO2) = 3.33 moles HNO3

Next, we calculate the moles of HNO3 produced from 2 moles of water:

2 moles H2O * (2 moles HNO3 / 3 moles NO2) = 1.33 moles HNO3

Since 1.33 moles of HNO3 is less than 3.33 moles of HNO3, the limiting reactant is water.

Therefore, the number of moles of nitric acid produced starting from 5.00 moles of NO2(g) and 2.00 moles of water is 1.33 mol.

The correct answer is 1.67 mol.

To find the answer, we first need to determine the balanced chemical equation for the reaction between NO2(g) and water to produce nitric acid (HNO3). The balanced chemical equation is:

3 NO2(g) + H2O(l) --> 2 HNO3(aq)

From the equation, we can see that for every 3 moles of NO2, we produce 2 moles of HNO3.

Next, we need to determine which reactant is limiting to calculate the moles of nitric acid produced. To do this, we can use the concept of stoichiometry.

The reactant that produces the least amount of product is the limiting reactant. So, let's determine the moles of nitric acid produced from both NO2(g) and H2O, and then compare them.

From the given information, we have:
- 5.00 moles of NO2(g)
- 2.00 moles of H2O

Using the balanced chemical equation, we can calculate the moles of nitric acid produced from each reactant:

From NO2(g):
Since the stoichiometric ratio is 3 moles of NO2(g) to 2 moles of HNO3, we can calculate the moles of HNO3 produced using the following equation:

(5.00 moles NO2(g) * (2 moles HNO3 / 3 moles NO2(g)) = 3.33 moles HNO3

From H2O:
Since there are 2 moles of H2O and no coefficient in front of H2O in the balanced equation, it means that there is no limiting factor from the H2O. Therefore, the moles of nitric acid produced from H2O is:

2.00 moles H2O * (2 moles HNO3 / 3 moles H2O) = 1.33 moles HNO3

Now, we compare the moles of nitric acid produced from each reactant. The lower value, 1.33 moles, indicates that water is the limiting reactant.

Therefore, the number of moles of nitric acid produced is 1.33 mol (option "1.67 mol" is correct).