7.08 moles of ammonia (NH3) is formed in the following reaction. How many grams of hydrogen reacted?
3H2 + N2 + 2NH3

Mass = 21.24 g

Explanation:

Given data:

Number of moles of ammonia = 7.08 mol

Mass of hydrogen reacted = ?

Solution:

Chemical equation:

3H₂ + N₂      →    2NH₃

Now we will compare the moles of ammonia and hydrogen.

             NH₃        :         H₂  

              2           :         3

          7.08         :        3/2×7.08 = 10.62

Mass of hydrogen:

Mass = number of moles × molar mass

Mass = 10.62 mol × 2 g/mol

Mass = 21.24 g