Chapter 19: Water Flashcards

1
Q

Hard water

A

Water that does not easily form a lather in soap

Causes by Ca2+ or Mg2+ ions I’m water

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2
Q

How is Scum formed

A

Calcium or magnesium ions react with stearate ions to form calcium stearate (scum)

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3
Q

Temporary Hardness

A

One that can be removed by boiling water

• Caused by calcium hydrogen carbonate

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4
Q

Permanent Hardness

A

Hardness that cannot be removed by boiling

Magnesium sulfate, calcium sulfate

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5
Q

Methods of Removing Hardness

A

Distillation
Zeolites
Washing soda
Ion-exchange resin

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6
Q

Distilled water

A

Purest form

All dissolved and suspended solids and all dissolved gases removed

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7
Q

Buffer Solution

A

A solution that resists changes in pH

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8
Q

Water Treatments Stages

A
Screening 
Flocculation 
Sedimentation 
Filtration 
Chlorination 
Fluoridation 
pH adjustment
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9
Q

Flocculation

A

The coagulating of small suspended particles in water

Aluminium sulfate

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10
Q

Primary Treatment

A

Screening

Channels Settlement

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11
Q

Secondary Treatment

A

Oxidation and aeration of sewage

Micro-organisms decompose sewage

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12
Q

Tertiary Treatment

A

Prevention of eutrophication by removing nitrates and phosphates

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13
Q

Instruments to Analyse Water

A

pH measurement
AAS - Atomic Absorption Spectrometry
Colorimetry

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14
Q

Colorimetry

A

Amount of absorbance of light is proportional to the concentration of the solution

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15
Q

Free Chlorine

A

Chlorine that exists in the water as hypochlorous acid and hypochlorite ion

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16
Q

What produces hypochlorous acid

A

Calcium hypochlorite

17
Q

Combined chlorine

A

Chemicals combined with ammonia or organic nitrogen compounds in water