How many molecules of water are there in 8.050 x 103 grams of water?

2.71 × 10²⁰ molecules

Explanation:

Given data:

Mass of water = 8.050 × 10³ g

Number of molecules = ?

Solution;

First of all we will calculate the number of moles of water,

Number of moles = mass/molar mass

Number of moles =  8.050 × 10³ g / 18 g/mol

Number of moles = 0.45 × 10³ mol

1 mole contain 6.022 × 10²³ molecules,

0.45 × 10³  mol × 6.022 × 10²³ molecules / 1 mol

2.71 × 10²⁰ molecules

The number 6.022 × 10²³ is called Avogadro number.

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.