C4.7 + C4.8 - Titrations (Finished)

Question 1

What do titrations let you find?

Answer 1

Exactly how much acid is needed to neutralise a volume of alkali and vice versa. Can use this to work out the concentration of the acid/alkaline

Question 2

What is the ned point of the reaction (titrations)?

Answer 2

The point at which the acid and alkali have reacted completely

Question 3

How do you carry out a titration?

Answer 3

1) Use a volumetric pipette to add a set volume of alkali to a conical flask
2) Add two or three drops of indicator to the solution
3) Use a funnel to fill a beurette with some acid of known concentration. Record the initial volume of acid in it (measure from the meniscus)
4) Add acid to the alkali a bit at a time giving the conical flask a regular swirl.
5) The indicator will change colour when all alkali has been neutralised
6) Record the final volume of acid in the burette and calculate how much acid was used
7 eh

Question 4

What are two safety measures you can take when doing titrations?

Answer 4

• Wear eye protection

- Fill burette below eye level

Question 5

How can you increase the accuracy of tour titration?

Answer 5

• Take several concordant reeding
• Do a rough titration first to get an approximate idea of where the solution changes colour
• Calculate a mean of results excluding anomalies

Question 6

What are concordant results?

Answer 6

Two or more results within 0.1cm3 of each other

Question 7

Why is universal indicator not good for titrations?

Answer 7

The colour gradually changes but you need a sudden colour change at the end-point to judge when the acid and alkali have reacted

Question 8

What indicator did we use and what are it’s colours? For titration

Answer 8

Phenolphthalein, colourless in acid, pink in alkali

Question 9

Need to revise titration calculations on lerboodle

Answer 9

Ok