Calculations 3

Question 1

Equation for concentration

Answer 1

moles = concentration x volume

Question 2

What does concentration tell you?

Answer 2

how much of something you have in a given volume

Question 3

How do you do a titration?

Answer 3

1. using pipette, add specific volume of acid (or alkali) to conical flask
2. add 2-3 drops indicator
3. fill burette with alkali (or acid), read off initial volume
4. add alkali to acid & look for colour change, continuously swirl to make sure its completely mixed
5. once indicator permanently changes colour, stop burette & read off final volume - end point
6. repeat experiment until you get concordant results, make sure when you get to near previous end point, add alkali drop wise

Question 4

What colours do the indicators go in a titration?

Answer 4

methyl orange - acid=red, alkali=yellow
phenolphthalein - acid=colourless, alkali=pink
universal - don’t use, no clear chnage

Question 5

What is a burette?

Answer 5

holds reactant you know concentration of in titration, accurately measures volume added to conical flask

Question 6

What is a pipette?

Answer 6

accurately adds specific volume of reactant you don’t know concentration of to conical flask

Question 7

What is a conical flask?

Answer 7

holds reaction mixture, conical flask used to minimise splashing

Question 8

What is a white tile?

Answer 8

makes colour change of indicator clear