3g of magnesium reacted w 0.2 moles of ethanoic acid. Calculate the number of moles of magnesium used

0.1 moles of magnesium

Explanation:

Mg(s) + 2CH3COOH(aq) > Mg(CH3COO)2(aq) + H2(g)

Since the reaction is 1:2 in mole ratio,

1 mole of magnesium reacts with 2 moles of ethanoic acid

x moles of magnesium will react with 0.2 moles of ethanoic acid

2x = 0.2

x = 0.2/2 = 0.1 moles of magnesium used