How many moles are in 12.5 g of H2O

0.694 moles

Explanation:

We are given;

Mass of water as 12.5 g

We are required to calculate the number of moles of water;

We need to know the relationship between moles, mass and molar mass of a compound. That is; Number of moles = Mass : Molar mass

In this case;

Mass of water is 12.5 g Molar mass of water is 18.02 g/mol

Therefore;

Moles of water = 12.5 g : 18.02 g/mol

= 0.694 moles

Therefore, moles of water are 0.694 moles