, Test for presence of water CH15
if water present if water present
Cobalt (11) chloride paper
& anhydrous copper (11) sulfate
changes from blue to pink changes from white to blue
Tests for purity of water
pure substances have > pure water melts at o
a set mp/bp
> pure water boils at 100
impurities
> lower the melting point of ice
> increase the boiling point of water
Distilled water consists water molecules only , it has no impurities
unlike tap water (has dissolved solids like calcium salts d impurities
like chloride and aluminium ions) Thus to get accurate results
.
distilled water is used in practical chemistry
water from natural resources (rivers & lake)
contain : dissolved metal & plastics - sewage
Oxygen compounds a
↓
harmful >
-
nitrates from >
- phosphates from
microbes fertilisers fertilisers detergent
Benefical substances
in natural sources of water
>Dissolved Oxygen for aquatic life (breathing
-metal compounds provide essential minerals for growth
of plant/animal
,Harmful substances
in natural sources of water
> some metal (from industrial waste) can be toxic
compounds
>
Non-biodegradable plastic harm aquatic life
-
sewage contains harmful microbes that cause disease
> Nitrates& phosphates encourage growth of algae
.
Respiration of algae leads to deoxygenation of water
& damage to aquatic life/eutrophication)
Purification of domestic water ① screening
② coagulant
water passed thru ③ sedimentation
a metalgrid screen ① powdered carbon
cremoves large solids ( ⑤ filtration
↓ ⑥ chlorination
coagulants make fine SC
SC
particles dirtd impurities
of
= C
to clump together
↓
clumped particles
settle to bottom of
tank (sedimentation)
↓
Powdered carbon
removes unpleasant taste
&
odova chlorine added to kill
microbes & prevent
water seeps thry water-borne diseases
sand a gravel layers Cchlorination)
to remove fine
Cfiltration) parties
, Fertilisers (Ns P . K)
are chemical compound containing plant nutrients which are
essential for plant growth
>
- makes them grow faster
F
Fertilisers
>
- increases crop yield
18 -
24 - 12
Nitrogenous fertilisers
contains compounds that produce
ammonium/nitrate ions
Air around earth is called atmosphere
>
Atmosphere protects earth from excessive radiation of sun
and keeps earth warm
composition of clean dry air
~
Nitrogen 78 %
Oxygen 21 %
other gases remaining
(noble gas : argon
(CO2)
first calculate
% of oxygen in the
air
then subtract or
add according
whichever value
ur given
if water present if water present
Cobalt (11) chloride paper
& anhydrous copper (11) sulfate
changes from blue to pink changes from white to blue
Tests for purity of water
pure substances have > pure water melts at o
a set mp/bp
> pure water boils at 100
impurities
> lower the melting point of ice
> increase the boiling point of water
Distilled water consists water molecules only , it has no impurities
unlike tap water (has dissolved solids like calcium salts d impurities
like chloride and aluminium ions) Thus to get accurate results
.
distilled water is used in practical chemistry
water from natural resources (rivers & lake)
contain : dissolved metal & plastics - sewage
Oxygen compounds a
↓
harmful >
-
nitrates from >
- phosphates from
microbes fertilisers fertilisers detergent
Benefical substances
in natural sources of water
>Dissolved Oxygen for aquatic life (breathing
-metal compounds provide essential minerals for growth
of plant/animal
,Harmful substances
in natural sources of water
> some metal (from industrial waste) can be toxic
compounds
>
Non-biodegradable plastic harm aquatic life
-
sewage contains harmful microbes that cause disease
> Nitrates& phosphates encourage growth of algae
.
Respiration of algae leads to deoxygenation of water
& damage to aquatic life/eutrophication)
Purification of domestic water ① screening
② coagulant
water passed thru ③ sedimentation
a metalgrid screen ① powdered carbon
cremoves large solids ( ⑤ filtration
↓ ⑥ chlorination
coagulants make fine SC
SC
particles dirtd impurities
of
= C
to clump together
↓
clumped particles
settle to bottom of
tank (sedimentation)
↓
Powdered carbon
removes unpleasant taste
&
odova chlorine added to kill
microbes & prevent
water seeps thry water-borne diseases
sand a gravel layers Cchlorination)
to remove fine
Cfiltration) parties
, Fertilisers (Ns P . K)
are chemical compound containing plant nutrients which are
essential for plant growth
>
- makes them grow faster
F
Fertilisers
>
- increases crop yield
18 -
24 - 12
Nitrogenous fertilisers
contains compounds that produce
ammonium/nitrate ions
Air around earth is called atmosphere
>
Atmosphere protects earth from excessive radiation of sun
and keeps earth warm
composition of clean dry air
~
Nitrogen 78 %
Oxygen 21 %
other gases remaining
(noble gas : argon
(CO2)
first calculate
% of oxygen in the
air
then subtract or
add according
whichever value
ur given
