10D- comparing pH measurements Flashcards

1
Q

Define commercial indicator

A

An artificially prepared indicator

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2
Q

Define indicator

A

A substance that changes colour to indicate a pH range

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3
Q

Define litmus paper

A

Paper used to indicate the acidity or basicity of a substance

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4
Q

Define natural indicator

A

An indicator made from naturally sourced substances

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5
Q

Define pH meter

A

An instrument used to measure the pH of a substance

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6
Q

Acidity
definition(adj.)

A

-Acidity(adj.)=The
amount of acid in a substance

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7
Q

Alkalinity
definition(adj.)

A

-Alkalinity(adj.)=The
ability to neutralise an acid

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8
Q

Definition of proticity(aka basicity)

A

The number of replaceable hydrogens in the formula of an inorganic acid is called Basicity. Basicity is also known as Proticity

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9
Q

Define super acid

A

Super acid
definition=A superacid can be defined as an acid that is stronger than 100%
sulfuric acid.

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10
Q

Define super base

A

Inchemistry, asuperbaseis an extremely strongbase. There is no commonly accepted
definition for what qualifies as a superbase, but most chemists would
acceptsodium hydroxideas a ‘benchmark’ base just
assulfuric acidis a ‘benchmark’ acid
(seesuperacid).

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11
Q

how can we approximate pH

A

indicators- chemical compounds that change colours depending on the pH they are immersed in

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12
Q

what colour does litmus paper turn

A

blue litmus paper turns red in an acidic solution
red litmus paper turns blue in a basic solution

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13
Q

what are natural indicators

A

an indicator made from naturally sourced substances

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14
Q

what are commercial indicators

A

indicators that are prepared artificially

Felix=Indicators that are synthesised/man made

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15
Q

list some natural indicators

A

red litmus
blue litmus
turmeric
red cabbage juice
Coloured petals of some flowers such as hydrangea

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16
Q

list some commercial indicators

A

phenolphthalein
methyl violet
methyl orange
thymolphthalein
Universal indicator

17
Q

what does red litmus paper indicate

A

acid: red
base: blue
changes colour at pH of=7(CHECK)

18
Q

what does blue litmus paper indicate

A

acid: blue
base: red
changes colour at pH of=7(CHECK)

19
Q

what does turmeric indicate

A

acid: yellow
base: reddish brown
changes colour at pH of=7.4 and 8.6

20
Q

what does red cabbage juice indicate

A

acid: reddish
base: greenish yellow
changes colour at pH of=7

21
Q

what does phenolphthalein indicate

A

acid: colourless
base: pink
changes colour at pH of=8.3-10.0

22
Q

what does methyl violet indicate

A

acid: yellow
base: blue
changes colour at pH of=0.0-1.6

23
Q

what does methyl orange indicate

A

acid: red
base: yellow
changes colour at pH of=3.1-4.4

24
Q

what does thymolphthalein indicate

A

acid: colourless
base: blue
changes colour at pH of= 9.3 - 10.5

25
Q

how can more specific pH measurements be obtained

A

pH meters can be used to provide a specific, quantitative measurement of pH
they measure the difference in electrical potential between two probes due to the concentration of charged particles/ion in the solution

26
Q

what are strong acid pH’s

A

a solution with a pH of 3 or less is considered a strong acid

27
Q

what are strong base pH’s

A

a solution with a pH of 10 or higher is considered to be a strong base

28
Q

what pH does the universal indicator cover

A

0 to 14

29
Q

indicators accuracy and precision

A

low accuracy and low precision
indicators can only approximate pH range and the estimated pH of a given solution may differ greatly between trials

30
Q

calibrated pH meters accuracy and precision

A

high accuracy and high precision

31
Q

what is the accuracy of most pH meters

A

+-0.01 pH units

32
Q

What are the three types of indicators

A

1)natural indicators
2)Commercial indicators
3)pH meters

33
Q

What is a pH meter
and what does it measure, and how does it measure it.

A

-pH meter=
instrument= measures acidity or alkalinity in a solution
-pH meter does
this by reading the hydrogen ion concentration in the solution

34
Q

What is precision
and what is accuracy.

A

-precision and
accuracy=two ways to describe results when completing a process that is
repeated=
-precision=yield
results that are close to each other repeatedly
-accuracy=yield
results being close to the accepted or true value of the test.

35
Q

Colour or
universal indicator across pH

A

Imagine it as a
rainbow, with pH of 7 showing green. Anything less then pH 7 changes
substance colour towards red, and any pH more than 7 changes substance colour
towards purple.