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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: SoupeAuxChoux123321 on August 10, 2019, 08:43:12 AM

Title: finding the stoechiometric coefficient
Post by: SoupeAuxChoux123321 on August 10, 2019, 08:43:12 AM

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 :)

Title: Re: finding the stoechiometric coefficient
Post by: chenbeier on August 10, 2019, 08:57:59 AM

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.