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musti_rashid · May 2, 2012, 08:47 AM

3.0 g of magnesium was added to 12.0 g of ethanoic acid.
Mg + 2CH3COOH → (CH3COO)2Mg + H2

How many moles of hydrogen were formed?

Which mole ratio do I have to use..
2CH3COOH : H2
Or
Mg : H2?

Please help!

Chic_Bowdrie · May 14, 2012, 04:55 PM

Originally Posted by musti_rashid

3.0 g of magnesium was added to 12.0 g of ethanoic acid.
Mg + 2CH3COOH → (CH3COO)2Mg + H2

How many moles of hydrogen were formed?

Which mole ratio do I have to use..
2CH3COOH : H2 or Mg : H2 ??

The answer is determined by whichever reactant is limited, not by the equation's mole ratios. 3g of Mg is equivalent to about 0.12 moles. 12 g of ethanoic acid is 0.2 moles. From the equation, you know that at most 0.1 mole of Mg will react assuming all 0.2 moles of acid are used up. So regardless of which ratio you use, at most 0.1 mole of H2 will be produced.