THE MOLE CONCEPT?! i need help....

How many water molecules are contained in 0.15 g of tin (IV) chloride pentahydrate?

I need proper working out for this? and pleaseee explain step by step cause im a beginner.

Thank you so much!

350.7 is the molar mass of the tin (IV) chloride pentahydrate

write out the formula

SnCl4.5H2O
molar mass 350.7 g/mol

first determine the number of moles of SnCl4.5H2O

moles = mass / molar mass
= 0.15 g / 350.7 g/mol
= 4.277x10^-4 moles

Now, each SnCl4.5H20 has 5 H2O molecules bound to it.
So moles H2O = 5 x moles SnCl4.5H2O
= 5 x 4.277x10^-4 mol
= 0.002139 moles of H2O

Then convert moles H2O to molecules H2O
1 mole of anything is 6.022x10^23 units of that anything. This is called avagadros number.

So you can determine the number of H2O molecules by multiplying moles H2O by avagadros number

molecules H2O = moles H2O x 6.022x10^23 molecules/mol
= 0.002139 mol x 6.022x10^23 molecules/mol
= 1.288x10^21 molecules
= 1.3x10^21 molecules (2 sig figs)