How many molecules of NH3 are present in 107.1 g?

37.94  × 10²³ molecules of ammonia.

Explanation:

Given data:

Mass of ammonia = 107.1 g

Number of molecules = ?

Solution:

First of all we will calculate the number of moles of ammonia.

Number of moles = mass/molar molar mass

Number of moles = 107.1 g/  17 g/mol

Number of moles = 6.3 mol

Now we will use the Avogadro number to calculate the number of molecules.

 It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ molecules

6.3 mol  × 6.022 × 10²³ molecules / 1mol

37.94  × 10²³ molecules of ammonia.