Question

Given the following chemical equation, determine how many grams of N2 are produced by 9.27 g of H2O2 and 5.14 g of N2H4.

2H2O2+N2H4=4H2O+N2

Answer 1

Reaction:

2H2O2+N2H4----- > 4H2O+N2

In this problem we use given mass of reactants and find the moles and from moles we calculate the mole of N2. The reactant which gives less number of moles of N2 is called as limiting reactant and the moles of N2 are used to calculated its mass formed since it is the maximum mass that could be formed in this reaction.

Mol = m / molar mass, m is mass in g , and

Mole ratio between

H2O2 : N2 , is 2 : 1

N2H4 : N2 is 1 : 1

n N2 from moles of H2O2 = 9.27 g x (1mol/34.0147g ) x (1 molN2 / 2 mol H2)

            =0.136 mol N2

n N2 from N2H4 = 5.14 g x ( 1 mol/ 32.0452 g ) x (1 mol N2/ 1 mol N2H4)

            = 0.160 mol N2

We can see that H2O2 is limiting reactant. So moles of N2 from it will be used to find mass.

Mass of N2 = mol x molar mass

            = 0.136 mol N2 x 28.0 g / mol

            = 3.82 g N2

Mass of N2 produced = 3.82 g