Limited Reactants

Question 1

Which one is the limiting reactant?
“4.8 grams of magnesium is reacted with 7.3 grams of hydrochloric acid. Mg + 2HCl = MgCl2 + H2
Which one is the limiting reactant?”

Answer 1

Mg
Mass = 4.8g
Mr = 24
Moles = 4.8/24 = 0.2

HCl
Mass = 7.3g
Mr = (remember ignore every number) 1 + 35.5 = 36.5
Moles = 7.3/36.5 = 0.2

Since in the formula it is 2HCl then there are 2 as much moles so 0.2 x 2 = 0.4 moles of HCl reacts with 0.2 moles of Mg.

0.2 moles of Mg would need 0.4 moles of HCl. With only 0.2 moles of HCl, this is the limiting reactant.

Question 2

“The amount of product formed is ……………………………….. to the amount of limiting reactant.”

Answer 2

Directly proportional