Question

If 12.2g of 2VH2 reacts with N2 to create 78.9g of 2NH3, how much N2 reacts?

a) 2.6g
b) 5.2g
c) 7.8g
d) 10.4g

Answer 1

To determine the mass of N2 that reacts, we need to convert the given amount of NH3 to moles and then use the balanced chemical equation to find the moles of N2 that react. Finally, we can convert the moles of N2 to grams.

Step-by-step explanation:

First, we need to determine the molar mass of NH3. It consists of 1 nitrogen atom with a molar mass of 14.01 g/mol and 3 hydrogen atoms with a molar mass of 1.01 g/mol each. So, the molar mass of NH3 is 14.01 g/mol + 3(1.01 g/mol) = 17.04 g/mol.

Next, we can use the molar mass of NH3 to convert the given amount of NH3 (78.9 g) to moles. This can be done using the formula: moles = mass / molar mass. Thus, moles of NH3 = 78.9 g / 17.04 g/mol = 4.62 mol.

Since the balanced chemical equation shows that 2 moles of NH3 react with 1 mole of N2, we can say that 4.62 mol of NH3 would react with 4.62 mol / 2 = 2.31 mol of N2. To find the mass of N2, we can use the formula: mass = moles x molar mass. Therefore, mass of N2 = 2.31 mol x 28.02 g/mol = 64.83 g.