Question

A fuel mixture used in the early days of rocketry is composed of two liquids, hydrazine (N2Ha) and dinitrogen tetroxide (N20a), which ignite on contact to form nitrogen gas and water vapor. What is the balanced chemical formula for the reaction?a⅔Hy a. How many grams of nitrogen gas form when 1.00 x 102 g of hydrazine and 2.00x 102 g dinitrogen tetroxide are mixed? b. 2. mb 3.01 28 c. If 93.2 g of nitrogen gas are collected from the reaction, what is the percent yield?

Answer 1

a) The balanced reaction is : 2N2H4 (l) + N2O4 (l) ----> 4N2(g) + 8H2O(g)

Molar mass(g/mol) 32 92 28 18   

b) From the above reaction 2 mol =2x32 g of N2H4 reacts with 1 mole = 92 g of N2O4

M g of N2H4 reacts with 200 g of N2O4

M = ( 2x32x200)/92 = 69.6 g of N2H4

So 100 - 69.6 = 30.4 g of N2H4 left unreacted so it is excess reactant.

Since all of N2O4 completly reacted it is limiting reactant.

Again from the reaction ,

92 g of N2O4 produces 4 mol = 4x28 g of N2

200 g of N2O4 produces ( 200x4x28)/92 = 243.5 g of N2 ---> This is the theoretical yield

c) Percentage yield = ( actual yield / theoretical yield) x 100

= ( 93.2 g / 243.5 g ) x 100
= 38.3 %