4.)How many molecules of water are there in 29.76g of FeCl3 · 6 H2O?

Question

if someone could just tell me how to find molecules of h2o in a hydrate that would help...you dont have to solve it thanx!!

Answer 1

3.98 x 10^23 water molecules.
To know the number of water molecules, get the number of moles first of the hydrated compound then get the number of molecules of the compound by multiplying it with the Avogradro's number 6.02 x 10^23. Finally, multiply the result with the number of water molecules in the compound (ie. for FeCl3 · 6 H2O, there are 6 water molecules).

Answer 2

The chemical formula you have of the hydrate is FeCl3.6H2O.
This means for every mole of the hydrate you have 6 moles of water molecules.
Thus you need to find out, how many moles of the hydrate are there in 29.76g.
Mr of FeCl3.6H2O = 56 + 3(35.5) + 6[ 2(1)+16 ] = 270.5
Moles of hydrate = (29.76)/270.5 = 0.1100 (to 4 s.f)
Moles of water present = 6 x 0.1100 = 0.6600
Hence molecules of water present
= (0.6600) x 6.023x10^23
= 3.98 x 10^23 (to 3.s.f.)

Answer 3

Calculate the molecular weight of the hydrated compound. Then determine the number of moles of it in 29.76 grams. Multiply that by 6 to get the number of moles of water, and multiply that by 6.023E23 to get the actual number of molecules of water.

Answer 4

number of molicules is solved with Avogadro's number-
so 6moles x 6.02 x 10 to the 23rd