Quantitative Chemistry Flashcards
How do you work out the percentage of an element by mass?
Total mass of atoms in element/Mr
(X100)
How do you work out the amount of moles in a substance?
Mass/Mr
How to warm out the mass of a substance?
Moles x Mr
What is the limiting reactant?
The reactant which is all used up
What is the excess?
The reactant which is left over
Give three reasons why the mass of product obtained in some reactions is less than would be expected based on a reacting mass calculation:
Reaction did not go to completion
Side reactions occurred
Loss of product during mechanical transfer
How to work out the percentage yield?
Actual yield/Theoretical yield x100
What is the theoretical yield?
The maximum mass of substance obtained based on a reacting mass calculation m
What is water of crystallisation?
Water which is chemically bonded into the crystal structure
What does hydrated mean?
Solid crystals contain water of crystallisation
What does anhydrous mean?
The substance does not contain water of crystallisation
What is dehydration?
The removal of water of crystallisation
How to work out the percentage of water of crystallisation?
Total Mr of water/Mr x100
What happens to metal carbonated when they are heated?
They decompose forming the oxide and releasing Carbon dioxide
