What is the molecular formula?
The exact number of each type of atom in a compound.
E.g - carbon dioxide = CO2 / hydrogen chloride = HCL
What is the relative formula mass?
Mr of a compound - its the relative atomic masses (Ar) of all the atoms in its formula added together.
What’s the empirical formula?
The simplest whole number ratio of each type of atom in a compound.
E.g - C6H12O6 = CH2O - empirical formula of glucose.
What is a mole?
1 mole of any substance is equal to the Ar or Mr in grams.
What are the equations for moles?
Mass = moles X Ar/Mr
Moles = concentration X volume
How can you calculate the amount of product from the limiting reactant?
- Write out a balanced equation.
- Work out relative formula masses (Mr) of the reactant and product you’re interested in.
- Find out how many moles there are of the substance you know the mass of.
- Use the balanced equation to work out how many moles there’ll be of the other substance.
- Use the number of moles to calculate the mass.
What is the limiting reactant?
The reactant that’s used up in a reaction, because it limits the amount of product that’s formed.
What happens to the mass in a chemical reaction?
Its always conserved.
Why would the mass change?
Hasn’t all reacted
If gas gets in and reacts.
If gas leaves, the mass will decrease.
