Limiting reactants

Question 1

what is a limiting reactant?

Answer 1

the reactant that is used up FIRST

Question 2

what do we call it when a reactant is not a limiting reactant?

Answer 2

the reactant is in EXCESS

Question 3

How would you find the limiting reactant?

Answer 3

you woud usually need to work out the mass of each reactant, then figure out which one is less

Question 4

true or false: a question on limiting reactants will usually require you to find the mass of a reactant?

Answer 4

FALSE: they will usually require you to find the maximum mass of product that can be made - you will need to use limiting reactants for this - usually given

Question 5

therefore, what are the steps to finding the unknown mass of a product from the limiting reactant? use the question: if 213g of Cl2 reacts with excess potassium bromide, what is the maximum amount of potassium chloride produced? equation: Cl2 + 2KBr = Br2 + 2KCl

Answer 5

1) find moles of Cl
moles = mass/Mr
moles = 213/71 = 3
2) use molar ratio to find moles of unknown
ratio = 1:2
3:6, so 6 moles of 2KCl
mass = moles x Mr
mass = 6 x 74.5 = 447g
answer = 447g