In a 5.609g of H20, how many molecules H20
arc
present?

1.88 x 10²³molecules of H₂O

Explanation:

Given parameters:

Mass of H₂O  = 5.609g

Unknown:

Number of molecules of  H₂O  = ?

Solution:

To solve this problem, we need to find the number of moles of given compound first.

 Number of moles  =  

Molar mass of  H₂O = 2(1) + 16  = 18g/mol

 Number of moles  =   = 0.31mole

From mole concept;

            1 mole of a substance contains 6.02 x 10²³molecules

       0.31 mole of H₂O will therefore contain 0.31 x 6.02 x 10²³molecules

                                             = 1.88 x 10²³molecules of H₂O

- lead + phosphoric acid = hydrogen + lead(ii) phosphate