8D.2 Flashcards

1
Q

what is titration

A

it is a practical method with the aim of measuring volumes of two solutions that react together, and then using that value to then find the concentration of one of the solutions

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2
Q

what are acid alkali tirtrations

A

they are titrations between acid and soluble bases

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3
Q

the colour of the acids and the alkalis are??

A

colourless in this method

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4
Q

what is the outline of the acid-alkali titration method

A
  1. add the acid to the alkali until the equivalence point and when the indicator has reached its endpoint
  2. you are going to record the burette reading using the lowest part of the meniscus
  3. calculate the titrate
  4. repeat the experiment until coordinate results are reached
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5
Q

what is the equivalence point

A

the point where there is the right amount of substance to complete a reaction

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6
Q

what is the endpoint

A

the point where the indicator changes colour. ideally, it should consider the equivalence point

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7
Q

what is a meniscus

A

the curving of the upper surface of a liquid and you should take a reading from the lowest (horizontal) part of it

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8
Q

what is the titrate

A

the volume added from the burette doing titrations

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9
Q

what are concordant results

A

two titrates that are very close to each other within a 0.2 diff

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10
Q

what is the method of acid-alkalis titrations

A

page 220

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11
Q

what is the apparatus used in the acid-alkalis titrations

A

pages 220

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12
Q

why is a white tile use

A

to see the colour change more clearly

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13
Q

why do we add 3 drops of indicator

A

each indicator used in an acid-alkalis base is a week acid, using it will have an effect on the endpoint of titrations, so it is important to use the same and little volume each time for more accurate results

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14
Q

why do we fill the space between the tap and the tip and the burette

A

if this is not done and we turn on the tap some of the liquid will fill the space and won’t enter the conical flask so we won’t have an accurate titrate at the end

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15
Q

why do we set up the burette so its tip is in the conical flask

A

so we would minimize the risk of some of the acid going outside the conical flask

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16
Q

why do we read the burette to the nearest half 0.05 cm at the bottom of the meniscus

A

to increase the accuracy of the reading

17
Q

why do we add the NH2SO3H steadily into the conical flask then while approaching the endpoint we start adding slowly

A

to make sure not to overshoot the endpoint

18
Q

why are we always swirling the conical flask

A

to make sure that the two solutions are always mixing

19
Q

why would we repeat the experiment till we get concordant results

A

to increase the accuracy

20
Q

why do why not rinse the conical flask with both the solution and the distilled water

A

because then we would have an unknown extra amount of sodium being titrated that we don’t know about

21
Q

whta are the two common indicators used in an acid-alkali titration

A
  1. methyl orange

2. phenolphthalein

22
Q

what is the colour of methyl orange in acid

A

red

23
Q

what is the colour of phenolphthalein in acid

A

colourless

24
Q

what is the colour of methyl orange in alkali

A

yellow

25
Q

what is the colour of phenolphthalein in alkali

A

pink

26
Q

what solution combination that phenolphthalein is used in

A

weak acid-strong base

strong acid- strong base

27
Q

what solution combination that methyl orange is used in

A

strong acid-week base

strong acid-strong base

28
Q

what is the weakest acid

A

ethanoic acid

29
Q

whats is the weakest base

A

ammonia

30
Q

what are the example of strong acid

A

HCl, nitric acid

31
Q

what is the example of a strong base

A

sodium hydroxide

potassium hydroxide