Calculate the atom economy for making hydrogen when zinc is reacted with HCL?

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So, there are two parts to this question. 

Firstly, you need to decode the words in the question and transform this into an equation. 

From chemical knowledge, you know: acid + metal --> salt + hydrogen 

So now: HCL + Zn --> ZnCl2 + H2 .... then we balance this to give: 2HCL + Zn --> ZnCl2 + H2 

Secondly, we need to recall the atom economy equation (Mr of desired product / Mr sum of all products  x 100) i.e. what you need/everything produced  x 100  

Desired product Mr i.e. of H2 is: 1 x 2 = 2

All products Mr i.e. ZnCl2 + H2 is: 65 + (2 x 35.5) + (1 x 2) = 138 

2/138 x100 =1.45% :)

Pooja D. GCSE Chemistry tutor, A Level Chemistry tutor, GCSE Biology ...

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