Hello, Adama,
We know the mass of both the resulting dehydrated salt and the water removed. We should convert nthese masses into moles of those components.
The molar mass of CsCl is 168.41 g/mole. Water is 18.0 g/mole.
Divide the two masses by their respect molar masses to find moles of each:
CsCl = 1.8115 moles
H2O = 16.308 moles
We need whole numbers, so lets divide moles H2O by moles CsCl: = 9.003 moles H2O/mole CsCl.
That gives us the formula for the hydrate: CsCl*9H2O
=
The name for BaS▪5 H2O is barium sulfide pentahydrate. Use this hint to name RaO▪2 H2O.
The percent composition of each element in BaS*5H2O is found by assuming we have 1 mole of the compound (for convenience). That would mean we have one mole of Ba, one mole of S, 10 moles of H, and 5 moles of O.
Make a table of each element and it's molar mass. Be sure to account for multiple atoms of the same element:
I don't have room for the entire table, but it looks like this:
Add the mass of all the elements to find the molar mass of BaS*5H2O. I got 259.4 g/mole.. Then divide the actual mass of each by the total mass (259.4g, since we assumed 1 mole) to determine percentage of each..
Bob
