Question

some rocket engines use a mixture of hydrazine,N2H4 and hydrogen peroxide ,H2O2 as the propellent . the reaction is given by the following equation N2H4 + 2H2O gives N2 GAS + 4 H2O .how much of the excess reactant,remains unchanged? when 0.850 mol of N2H4 is mixed with 17 g of H2O2 ?

Answer 1

Hi,

Let us go through the question once again; some rocket engines use a mixture of hydrazine,N2H4 and hydrogen peroxide ,H2O2 as the propellent . the reaction is given by the following equation N2H4 + 2H2O gives N2 GAS + 4 H2O .

Then you are required to determine how much of the excess reactant,remains unchanged when 0.850 mol of N2H4 is mixed with 17 g of H2O2

So what you need to do is to determine the number of moles of hydrogen peroxide;

moles = mass/molar mass

moles = 17/34

           = 0.5 moles

So excess number of moles that remains unreacted is (0.85 - 0.5) = 0.35 moles.

therefore from this, it is evident that hydrazine was in excess. So the amount of hydrazine remaining unchanged is;

mass= moles x molar mass of hydrazine

         = 0.35 x 32

        = 11.2 grams