C3 - Moles & Titration Flashcards
What is the concentration of a substance?
The amount of substance in a given volume
What is one mole of a substance?
The relative atomic mass in grams
What is concentration measured in?
Moles per dm^3
Or
Grams per dm^3
What do titrations tell us?
How much acid is needed to neutralise an alkali or vice versa
Describe how to do a titration
You put some alkali in a flask with some phenolphthalein indicator
Put the acid into a burette and add it to the flask a bit at a time, swirling the flask after every addition
When the indicator changes from pink to colourless, stop adding acid and record how much acid it took to neutralise the alkali
What colour is phenolphthalein in acid and alkali?
It is colourless in acid and pink in alkali
What is the formula triangle that tells us the concentration in moles per dm^3?
Number of moles is over concentration in mol/dm^3 and volume in dm^3
How do you calculate concentration in grams per dm^3?
Multiply the concentration in mol/dm^3 by the relative formula mass to get the concentration in g/dm^3
