Question

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

Answer 1

1.88 x 10²³molecules of H₂O

Step-by-step 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 =
`(mass)/(molar mass)`

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

Number of moles =
`(5.609)/(18)` = 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