[mohnish_khiani]

A sample of impure Magnesium is reacted with diluted Sulphuric Acid to
give the respective salt and Hydrogen.If 1 gram of impure sample gave
298.6 cc of Hydrogen at STP.Calculate the % purity of the sample
(Magnesium = 24,Hydrogen = 1)

[sjb]

A sample of impure Magnesium is reacted with diluted Sulphuric Acid to
give the respective salt and Hydrogen.If 1 gram of impure sample gave
298.6 cc of Hydrogen at STP.Calculate the % purity of the sample
(Magnesium = 24,Hydrogen = 1)

What is the balanced equation for the reaction?

[mohnish_khiani]

Mg(s) + H2SO4(aq) --> MgSO4(aq) + H2(g)

[Borek]

OK so far.

Can you calculate number of moles of hydrogen produced?

[mohnish_khiani]

I was posting this question on behalf of my mother,who is a teacher and had this doubt.I have no idea about this topic.Can someone please give me the solution,it's urgent I am sorry,

Just guessing,I think 1 mole of Magnesium would produce 1 mole of Hydrogen

[Borek]

I was posting this question on behalf of my mother,who is a teacher and had this doubt.I have no idea about this topic.Can someone please give me the solution,it's urgent I am sorry,

We don't give final solutions. Also, we ignore all stories about Moms/Dads/sisters/girlfriends learning/teaching chemistry. You would be surprised what lies people post in hope we will just give them the final answer.

Just guessing,I think 1 mole of Magnesium would produce 1 mole of Hydrogen

That's correct, and we will use of that later, but it is not what I asked to calculate now.

Does your Mom know ideal gas equation?

[mohnish_khiani]

Okay,let me try this one.

 

A pure sample of 1 mole of Magnesium would give 1 mole of Hydrogen. But since 1 mole of magnesium gives 0.2986 moles of hydrogen. The purity of Magnesium would be 29.86%. Am I right ??

[Borek]

298.6 cc of hydrogen is not 0.2986 moles of hydrogen. This is where you need to use the ideal gas equation, or check what is the volume of 1 mole of gas at STP.

Then, you can't directly divide number of moles by mass - you have to convert moles to mass first.