# Calculating what I need for a displacement reaction

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I have some copper sulfate in solution along with various metals which should react and cause a displacement reaction for example

Mg

Zn

Al

If I make up a 0.1 molar solution of copper sulfate at 100ml volume I need 2.49g of copper sulfate in 100ml water.   This is fine.

Now if I wanted to add just enough of one of the above metals to displace all the cooper do I calculate as follows

( I could look this up, but I have an idea of how to do this, so am asking to see if I am on the right track)

So if 1 M of Copper sulfate weighs 249g

if mass of copper is 63.54 g  then calculating the % composition gives

63.54 / 249 = 0.26  x 100 = 26%

So if I have a 0.1 M solution, and used 2.49 g of the copper sulfate do I then work out what 26% of that is with

0.26 x 2.49 = 0.65g

So I need 0.65g of one of the above metals to displace the copper

I think I am nearly there with this,  but given Magnesium , Aluminium and zinc all have different weights do I need to factor in the atomic mass of the element I am using for the displacement ?

Or just weigh out say 0.65g of Magnesium to produce

CuSO_4 5H_2O (solution) + Mg = MgSO4 (solution) + Cu + H20

I am not quite sure what happens to the 5H_2O here.

Am I right on my thinking here ?

Thanks

Paul

Edited by paulsutton

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