If I have 85 g of NH3 , how many grams of Nitrogen will result from the decomposition of all of the NH3 molecules?

Mass of nitrogen produce as a result of decomposition of ammonia = 70 g

Explanation:

Given data:

Mass of ammonia = 85 g

Mass of nitrogen produce = ?

Solution:

Chemical equation:

2NH₃    →  N₂  + 3H₂

Number of moles of ammonia:

Number of moles = mass/molar mass

Number of moles = 85 g/ 17 g/mol

Number of moles = 5 mol

Now we will compare the moles of ammonia with nitrogen.

            NH₃         :         N₂

               2           :         1

               5           :      1/2×5 = 2.5 mol

Mass of nitrogen:

Mass = number of moles × molar mass

Mass = 2.5 mol × 28 g/mol

Mass = 70 g