[SoupeAuxChoux123321]

Hi everybody Can someone help me with this question please? (I apologise if there are mistakes, English is not my mothertongue )

The hydrated nickel (II) chloride (NiCl2.xH2O) is a green crystalline solid. Heavily heated, a 0.238g sample of this compound dehydrates.
What is the value of x knowing that there remains 0.130g of solid after heating?
Answer:6

Okay so I substracted 0,130g to 0,238g which gives me 0,108g of water. With this and the molar mass, I can easily find the mole number: 6*10^-3. But I Don't really understand know what I have to do

[chenbeier]

You have to calculate the mole of the dry Nickel Chloride . This is equal of the hydrated  one. Convert back to the molar mass of this one and make difference you will get molar mass of x water. Divide by the molar mass of water gives number of water molecule in 1 mole of the salt.