How many moles of H2O are in 12.7 grams of H2O?

Moles = grams/molar mass

Note that the molar mass of H2O is 18 g/mol.

If you're not sure how to calculate for the molar mass, get a periodic table and look for the individual masses of the elements present in the chemical formula. For instance, in the periodic table,
H has mass of 1 g
O has mass of 16 g
Therefore,
H2O: 2*1 + 1*16 = 18 g/mol

Then to get the number of moles, we divide the given mass by the molar mass:
12.7 / 18 = ?

hope this helps~ `u`

To find the number of moles of H2O in 12.7 grams, you need to use the formula:

moles = mass / molar mass

Step 1: Find the molar mass of H2O.
The molar mass of H2O is calculated by adding the atomic masses of hydrogen (H) and oxygen (O) in the water molecule.

H2O:
- Hydrogen (H) has an atomic mass of 1.00784 grams/mole (approximated as 1 g/mol).
- Oxygen (O) has an atomic mass of 15.999 grams/mole (approximated as 16 g/mol).

So the molar mass of H2O = (2 * 1 g/mol) + 16 g/mol = 18 g/mol.

Step 2: Plug the values into the formula.
moles = 12.7 g / 18 g/mol

Divide 12.7 g by 18 g/mol to find the number of moles.

moles = 0.70556 moles

Therefore, there are approximately 0.71 moles of H2O in 12.7 grams of H2O.