Answer:
1.67 ×10²³ atoms of hydrogen present in 2.5 g of water.
Step-by-step 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