How many atoms of hydrogen are in 2.50g of water

1.67 ×10²³ atoms of hydrogen present in 2.5 g of water.

Explanation:

Given data:

Mass of  water = 2.5 g

Number of hydrogen atoms= ?

Solution:

First of all we will calculate the molar mass of water.

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

The number of atoms will be determine through the Avogadro number.

The number 6.022×10²³ is called Avogadro number and it is the number of atoms or molecules in one gram of atoms of an element or one gram molecules of a compound.

First of all we will calculate the number of moles of water in 2.5 g.

Number of moles = mass /molar mass

Number of moles = 2.5 g / 18 g/mol

Number of moles = 0.139 mol

The number of molecules of water in 10 g.

0.139 × 6.022×10²³ = 0.837 ×10²³molecules

one water molecule contain two hydrogen atoms. For 0.837×10²³ molecules,

0.837×10²³× 2 = 1.67 ×10²³ atoms