What is the mass of one mole of water?

Question

atomic mass of water: 18.01528
A student purchases 500.0 grams of drinking water?

then answer the folowing:
1. How many moles of water are contained in the bottle?
2. How many water molecules are contained in the bottle?
3. How many oxygen atoms are contained in the bottle?
4. How many hydrogen atoms are contained in the bottle?

please show work
thank you

Answer 1

Well, if you know the atomic mass, you know the mass of one mol.

One mol = 6.022 *10^23 atoms or molecules, and the molecular mass you have there is the mass of one mol of molecules in a pure sample.

So, one mol H2O is 18.05128 g

What's up with the second question - is it how many moles of water the person has?

In that case, just go with (1 mol/18.01528 g)(500g) = ??? mol

Answer 2

to figure out how many grms of 1 mole of h20 you:

1) double the atomic mass of hydrogen becasue there are to hydrogen atoms in H20 ( you get 2.01588)

2) then you find the mass of oxygen which is 15.9994

3) add the mass of the 2 hydrogens to the mass of the oxygen and you get 18.01528

Answer 3

Mass of one mole of water is 18.01528g

1)
500.0g water *(1 mol/18.01528g water)=27.75 mol water in the bottle

2)
27.75 mol water *(6.022e23 molecules/1 mol)=1.671e25 water molecules

3) One O atom in each molecule so 1.671e25 O atoms in the bottle

4)
Two H atoms in each molecule so 3.343e25 H atoms in the bottle