[liukawa]

Hi Guys,

I have a high school question which I need help urgently . Appreciate if anyone can help !

The question is as follows :

"The metal nickel (Ni) has a valency of 2. When excess sodium hydroxide solution was added to a solution of nickel chloride, nickel hydroxide was precipitated. This precipitate was filtered, washed and heated , leaving a residue of 0.747g of pure nickel oxide. This residue, when heated in a steam of hydrogen, gave 0.590g of metallic nickel.

(a) Write equations with state symbols for the three chemical referred to above.

I manage to come up with these 3 equations.

1. NiCL2 +2NaOH   2NaCL + Ni(OH)2

2. Ni(OH)2 + O2   NiO + H2O

3. NiO + H2   Ni +H2O

Are my equations correct?

I can't seem to balance the 2nd equation so i suspect my 2nd equation is wrong...

But I have no idea what equation should be formed....

I will also need to calculate the mass of nickel chloride present in the original solution .

Greatly appreciate if any kind souls can help.

Thanks !

Edit: tags corrected

[Borek]

Nickel hydroxide doesn't react with oxygen, just decomposes.

How many moles of Ni in each step?

[liukawa]

Decompose meaning?

Nickel Hydroxide will decompose to become Nickel and Hydrogen?

Is that right?

[Borek]

Nickel Hydroxide will decompose to become Nickel and Hydrogen?

That would mean oxygen miraculously disappeared.

Your original equation was almost right. Just ignore the oxygen.

[PeonyHamster]

I think the second equation is
Ni(OH)2 -> NiO + H2O

[Borek]

I think the second equation is
Ni(OH)2 -> NiO + H2O

You think right, but it is not you who should answer this question.