C4: Indicators and pH Flashcards

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1
Q

Acids all taste…

A

sour

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2
Q

Alkalis all feel…

A

soapy

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3
Q

Vinegar, oranges and lemons all contain an acid or alkali?

A

Acid

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4
Q

Toothpaste, soap and bleach all contain an acid or alkali?

A

Alkali

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5
Q

What are the main hazard linked to acids?

A

They are corrosive / irritants (will burn your skin or eyes)

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6
Q

What safety precautions can we take when working with acids and alkalis?

A

Wear safety glasses Wear gloves

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7
Q

Which type of acid is found in your stomach?

A

Hydrochloric Acid

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8
Q

What is the scientific name for acid particles?

A

H+ (hydrogen ions)

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9
Q

What is the scientific name for alkali particles?

A

OH- (hydroxide ions)

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10
Q

What is an indicator?

A

Something that tells us if a substance is an acid or alkali.

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11
Q

How do indicators work?

A

They contain a dye which changes colour in acidic and alkaline conditions.

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12
Q

You add blue litmus paper to an unknown solution and it turns red.

You add red litmus paper to an unknown solution and it stays red.

The substance is…

A

Acidic

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13
Q

You add red litmus paper to an unknown solution and it turns blue.

You add blue litmus paper to an unknown solution and it stays blue.

The substance is…

A

Alkaline

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14
Q

You add blue litmus paper to an unknown solution and it stays blue.

You add red litmus paper to an unknown solution and it stays red.

The substance is…

A

Neutral

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15
Q

If you want to know exactly how acidic or alkaline a substance is then we use which indicator?

A

Universal Indicator

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16
Q

pH1 =

A

Strong acid (red)

17
Q

pH3 =

A

Strong acid (orange)

18
Q

pH5 =

A

Weak acid (orange)

19
Q

pH6 =

A

Weak acid (yellow)

20
Q

pH7 =

A

Neutral (green)

21
Q

pH9 =

A

Weak alkali (blue)

22
Q

pH10 =

A

Weak alkali (purple)

23
Q

pH12 =

A

Strong alkali (purple)

24
Q

pH14=

A

Strong alkali (purple)

25
Q

Give an example of useful neutralisation reactions.

A

Toothpaste is alkaline to neutralise the acids produced by bacteria that cause acid erosion of teeth

Indigestion tablets neutralised excess stomach acids to prevent heartburn/indigestion.