Given the following reaction, how many liters of H2 gas are needed to form 35.5 grams of NH3? N2 + 3H2 -> 2NH3

170.4L

Explanation:

The reaction equation is given as:

        N₂  +   3H₂  →    2NH₃  

Mass of NH₃    =  35.5g

Problem:

How many liters of H₂ are needed to produce 35.5g of NH₃  

Solution:

To solve this problem, let us find the number of moles of NH₃;

           Number of moles  =

Molar mass of NH₃   = 14 + 3(1)  = 17g/mol

 So;

            Number of moles  =  = 5.07mole

From the balanced reaction equation:

               2 mole of NH₃   will be produced from 3 mole of H₂  

               5.07mole of NH₃ will produce     = 7.61mole of H₂

At STP;

       1 mole of gas will occupy 22.4L

     7.61 mole of H₂ will occupy 7.61 x 22.4  = 170.4L