Question

How many molecules of NH3 are produced from 8.01x10-4g of H2

Answer 1

Answer:

1.61 x 10²⁰ molecules

Explanation:

Given parameters:

Mass of the hydrogen gas  = 8.01 x 10⁻⁴g

Unknown

Number of molecules of NH₃ = ?

Solution:

Given reaction:

                     N₂  +  3H₂   →   2NH₃

We have to solve from the known to the unknown

• The known specie is the mass of H₂ ;

             find the number of moles of the specie;

    number of moles = $\frac{mass}{molar mass}$

     Molar mass of H₂ = 2(1) = 2g/mol

   Number of moles  = $\frac{0.0008}{2}$   = 0.0004mol

• 3 moles of H₂   will produce 2 moles of NH₃

      0.0004 moles of H₂ will produce $\frac{0.0004 x 2}{3}$   = 0.00027moles of NH₃

   1 mole of a substance contains 6.02 x 10²³ molecules

     0.00027mole of NH₃ will contain 0.00027 x 6.02 x 10²³

                               = 1.61 x 10²⁰ molecules