C5d- Titrations Flashcards Preview

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Flashcards in C5d- Titrations Deck (13)
1

What are titrations used for?

to find out concentrations of unknown reactants

2

What is the equation linking moles, concentration and volume?

Moles = concentration x volume

3

Interpret a PH curve which starts at ph 4 and ends at ph 12

an alkali has been added to an acid

4

What is the endpoint?

halfway down the vertical line

5

What is the equivalence point?

where the moles of acid is equal to the number of moles of alkali

6

What apparatus do you need in an acid base titration?

burette
conical flask
pipette
pipette filler

7

Why is it important to use a pipette filler?

to stop alkali getting in your mouth

8

What is the method for carrying out a simple acid base titration?

1) place the acid (or alkali) into a burette
2) place some alkali(or acid) into a conical flask using a pipette
3) add a suitable indicator (name it)
4) note the initial reading
5) add acid (or alkali) to the flask until the colour changes. Do this drop wise near the endpoint
6) note the final reading
7) repeat

9

What does concordant mean?

the same

10

What colour do litmus and phenolphthalein turn in alkali?

litmus - blue
phenolphthalein - red

11

What colour do litmus and phenolphthalein turn in acid?

litmus - red
phenolphthalein - colourless

12

Why should an acid base titration use a single indicator rather than a mixed one?

because you want a sudden colour change

13

25cm3 of 0.1 mol/dm3 NaOH is needed to neutralise 25cm3 of a solution of hydrochloric acid. How would you calculate the concentration of the acid?

1) find the known solution (the one with volume and concentration)
NaOH
2) calculate the number of moles of the 'known'
0.100 x (25 ÷ 1000) = 0.0025
3)write down the number of moles of the 'unknown' (the same as known)
0.0025
4) Calculate the concentration of the unknown
conc = moles ÷ volume
0.0025 ÷ 25 = 0.0001
0.1mol/dm3