539052
HARD WATER
- Soft Water
- Produces a
lather when it
reacts with soap
- comes from peat
or igneous rock
sources, such as
granite but may
also come from
sandstone sources,
since such
sedimentary rocks
are usually low in
calcium and
magnesium.
- Produces a
lather when it
reacts with soap
- Permanently Hard
Water
- Caused by the presence of
dissolved calcium sulfate
- CAN BE SOFTENED BY:
- Adding washing
powder (sodium
carbonate)
- The added carbonate
ions react with the
calcium and magnesium
ions. The calcium and
magnesium ions are no
longer dissolved in the
water.
- The added carbonate
ions react with the
calcium and magnesium
ions. The calcium and
magnesium ions are no
longer dissolved in the
water.
- Running
water through
'ion exchange
columns'
- The columns
have
sodium/hydrogen
ions and
exchange them
for the calcium
and magnesium
ions in the water
- The columns
have
sodium/hydrogen
ions and
exchange them
for the calcium
and magnesium
ions in the water
- Adding washing
powder (sodium
carbonate)
- Caused by the presence of
dissolved calcium sulfate
- Hard Water
- The scum produced
is insoluble
- Forms scale when heated
- Acts as a
thermal insulator
so a kettle (for
example)would
take longer to
boil
- The build up
eventually
results in the
blocking of
pipes
- This reduces
the efficiency of
the appliance,
therefore they
will need to be
regularly
replaced;
costing money
- Acts as a
thermal insulator
so a kettle (for
example)would
take longer to
boil
- Calcium ions are good
for healthy teeth and
bones. People drinking
hard water are less at
risk of developing heart
disease
- Calcium and
magnesium ions
make the water 'hard'
- The calcium
and magnesium
ions are
dissolved from
rocks (such as
limestone, chalk
and gypsum) as
magnesium
sulfate and
calcium sulfate
- The calcium
and magnesium
ions are
dissolved from
rocks (such as
limestone, chalk
and gypsum) as
magnesium
sulfate and
calcium sulfate
- The scum produced
is insoluble
- Temporarily Hard
Water
- CAN BE SOFTENED BY:
- Adding washing
soda (sodium
carbonate)
- The added carbonate ions react
with the calcium and magnesium
ions. The calcium and
magnesium ions are no longer
dissolved in the water
- The added carbonate ions react
with the calcium and magnesium
ions. The calcium and
magnesium ions are no longer
dissolved in the water
- Running water through
'ion exchange columns'
- The columns have sodium
(or hydrogen) ions and
exchange them for the
calcium and magnesium
ions in the water
- The columns have sodium
(or hydrogen) ions and
exchange them for the
calcium and magnesium
ions in the water
- Adding washing
soda (sodium
carbonate)
- Caused by the presence
of hydrogencarbonate
ions
- Removed by boiling
- The hydrogen-carbonate ions
decompose to form calcium carbonate
which is insoluble. This is called
limescale.
- The hydrogen-carbonate ions
decompose to form calcium carbonate
which is insoluble. This is called
limescale.
- CAN BE SOFTENED BY:
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