Question

How many water molecules are in a bottle of water that contains 500. g?

This is a two part conversion.

(1 mol H2O = 18.02 g) (1 mol = 6.02 x 1023 molecules)

Answer 1

Explanation:

no.of moles of water= mass of water /molar mass of water

molar mass of water= 2(molecular mass of hydrogen) + molecular mass of oxygen

molar mass = 2(1) + (16)

= 2+16

= 18 g/mol

no. of moles= 500g / 18g/mol

= 27.7 moles

Now number of water molecules= no of moles of water× no.of molecules in one mole

number of molecules= 27.7 × 6.02× 10 23

= 1.66× 10 25 molecules