Fundamentals E: Moles and Molar Mass Question #27

[Ben 1B]

What are the steps in solving question E.27 from Fundamentals E: Moles and Molar Mass?
Example:
(a) Calculate the mass, in grams, of one water molecule.
(b) Determine the number of H20 molecules in 1.00 kg of water.

[Daria Azizad 1K]

a.) Start with the molar mass of a single mole of water by adding the individual molar masses of O and H2

16.00+ 1.01*2= 18.02g/mol

In one mole of water, we know there are 6.02E23 molecules of water, therefore the ratio of water to molecules is 1:6.02E23. Use this to convert from g/mol to g/molecule.

(18.02g/mol)*(1mol/6.02E23mlc)= 2.993E-23g/molecule

b.) First convert kg to g (1kg = 1000g). Then, convert grams of water to moles of water, using water's molar mass. Using the same idea in (a), use the ratio of mlc:mol to convert from moles to molecules.

(1000g)*(1mol/18.02g)*(6.02E23mlc/1mol)=3.34E25 molecules