Topic 3 Limiting reactant

Question 1

What is the limiting reactant

Answer 1

The reactant that is used up in a reaction

Question 2

Why are other reactions added in excess

Answer 2

To make sure that the other reaction is used up

Question 3

What is the amount of product formed directly proportional to

Answer 3

Seamount of limiting reaction

Question 4

Why is the amount of product formed directly proportional to the limiting reactant

Answer 4

Because if you add more reactant there will be more reactant particles to take part in the reaction which means more product particles

Question 5

How to calculate mass of a product formed using mass of the limiting reactant

Answer 5

1). Write out the balanced equation
2). Workout relative formula mass of the reactants and products you want (Mr)
3). Find out how many moles there are a substance you know the mass of - moles = mass/ Mr
4). Use the balanced equation to work out how many miles there will be of the other substance (in this case that’s how many moles of the product will be made of this many moles of reactant
5). Use the number of moles to calculate the mass

Question 6

What is the mass of a product called

Answer 6

The yield of a reaction

Question 7

What are masses you calculate in this way called?

Answer 7

Theoretical yields

Question 8

If you never get 100% of the yield what does this mean about the amount of product

Answer 8

The amount of product you get will be less than you calculated