Question

Calculate the number of molecules in 3/2 litres of water.

Answer 1

The formula of water is H2O.
Its Mass is (1×2)+16 = 18.
This is 1 mole of water.
1 mole of any substance has 6.023×10²³ ions, particles or molecules.
1.5 litres of water = 1500 g of water.
No. Of moles in 1.5 litres of water = 1500/18 = 83.3....3 moles.
Therefore, 83.3...3 moles of water has 83.3...3 × 6.023×10²³
Which is equal to 5.016444278×10^25 molecules of water in 1.5 litres of water.