how many water molecules are in a 1.000 L bottle of water? (recall the density of water is 1.00 g/mL.)?

Question

i don't know to do this question....the answer is 3.34X10^25 molecules.

Answer 1

you need to know how many molecules of water are in 1g, it is a known fact and can probably be found in your text book or online (if it isn't given to you in the problem)... then you just multiply that by 1000 to get the number of molecules in 1L.

3.34x10^25 / 1000 = 3.34x10^22 molecules / ml....

Answer 2

1 mole is 18g. 1 mole is 6.23 x 10^23 molecules (Avogadro's number).
So 1000 L= 1000 kg = 55,555 moles= 34.6 x 10^27 molecules.