Topic 3 Limiting reactant Flashcards
What is the limiting reactant
The reactant that is used up in a reaction
Why are other reactions added in excess
To make sure that the other reaction is used up
What is the amount of product formed directly proportional to
Seamount of limiting reaction
Why is the amount of product formed directly proportional to the limiting reactant
Because if you add more reactant there will be more reactant particles to take part in the reaction which means more product particles
How to calculate mass of a product formed using mass of the limiting reactant
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
What is the mass of a product called
The yield of a reaction
What are masses you calculate in this way called?
Theoretical yields
If you never get 100% of the yield what does this mean about the amount of product
The amount of product you get will be less than you calculated
