Transcript No Slide Title

CALCIUM
CARBONATE
A guide for GCSE students
2010
KNOCKHARDY PUBLISHING
SPECIFICATIONS
CALCIUM CARBONATE
INTRODUCTION
This Powerpoint show is one of several produced to help students
understand selected GCSE Chemistry topics. It is based on the requirements
of the AQA specification but is suitable for other examination boards.
Individual students may use the material at home for revision purposes and
it can also prove useful for classroom teaching with an interactive white
board.
Accompanying notes on this, and the full range of AS and A2 Chemistry
topics, are available from the KNOCKHARDY SCIENCE WEBSITE at...
www.knockhardy.org.uk/gcse.htm
All diagrams and animations in this Powerpoint are original and
created by Jonathan Hopton. Permission must be obtained for their
use in any commercial work.
LIMESTONE
Limestone is made of calcium carbonate CaCO3
Origin
Formed in the sea millions of years ago
from the remains of shells
Found in places like the Peak District of Derbyshire
Extraction
Quarried in large amounts
e.g. 150 million tonnes each year in the UK
IT IS AN IMPORTANT RAW MATERIAL
Use
building material and road chippings
neutralising excess acid in lakes and soil
making cement and concrete
added to bread
added to toothpaste
LIMESTONE PRODUCTS ARE VERY USEFUL
… especially in building houses
CEMENT / MORTAR
GLASS
CONCRETE
CARBONATES
Formulae
All carbonates contain the CO3 unit
The compounds are ionic; the formula is found by
balancing the charges of the ions
Carbonate ions have a 2- charge
CO32CALCIUM CARBONATE
CaCO3
SODIUM CARBONATE
Na2CO3
CARBONATES
Formulae
All carbonates contain the CO3 unit
The compounds are ionic; the formula is found by
balancing the charges of the ions
Carbonate ions have a 2- charge
CO32CALCIUM CARBONATE
CaCO3
SODIUM CARBONATE
Na2CO3
CARBONATES
Formulae
All carbonates contain the CO3 unit
Chemical
formula
sodium carbonate
Na2CO3
calcium carbonate
CaCO3
magnesium carbonate
MgCO3
copper carbonate
CuCO3
CARBONATES
Formulae
All carbonates contain the CO3 unit
Chemical
formula
sodium carbonate
Na2CO3
calcium carbonate
CaCO3
magnesium carbonate
MgCO3
copper carbonate
CuCO3
PROCESSING LIMESTONE
Roasting
Heating limestone very strongly makes it break up
The process is known as THERMAL DECOMPOSITION
calcium carbonate
CaCO3
—>
—>
calcium oxide +
CaO
carbon dioxide
+
Calcium oxide is also known as QUICKLIME
CO2
ACTION OF HEAT ON METAL CARBONATES
METHOD
Place a small amount of one of the
solid carbonates in a dry test tube.
Place about 2cm3 of lime water in
another test tube. Heat the solid,
gently at first, then more strongly.
CO2
lime water
metal
carbonate
Test any gas with the limewater.
Appearance
Calcium carbonate
CaCO3
Copper carbonate
CuCO3
Magnesium carbonate
MgCO3
Zinc carbonate
ZnCO3
CO2 produced
Residue
Conclusion
ACTION OF HEAT ON METAL CARBONATES
Appearance
Calcium
carbonate
CaCO3
Copper
carbonate
CuCO3
Magnesium
carbonate
MgCO3
Zinc
carbonate
ZnCO3
CO2 produced
Residue
Conclusion
WHITE
SOLID

WHITE
SOLID
Calcium oxide
formed (needs very
GREEN
SOLID

BLACK
SOLID
Copper oxide
formed
WHITE
SOLID

WHITE
SOLID
Magnesium oxide
formed

YELLOW SOLID
WHICH TURNS
WHITE WHEN COOL
Zinc oxide
formed
WHITE
SOLID
strong heating)
Sodium carbonate (Na2CO3) also decomposes on heating but it requires more heat
than an ordinary bunsen burner can supply.
THERMAL DECOMPOSITION OF CARBONATES
All metal carbonates decompose when heated to form carbon dioxide and a
metal oxide. The process is known as THERMAL DECOMPOSITION
calcium carbonate
—>
calcium oxide
copper carbonate
—>
copper oxide
magnesium carbonate
—>
magnesium oxide
sodium carbonate *
—>
sodium oxide
+
zinc carbonate
—>
zinc oxide
carbon dioxide
+
+
+
carbon dioxide
carbon dioxide
+
carbon dioxide
carbon dioxide
* THE THERMAL DECOMPOSITION OF GROUP I METAL CARBONATES
(SUCH AS SODIUM CARBONATE) REQUIRES A TREMENDOUS AMOUNT OF ENERGY
– A BUNSEN BURNER IS NOT HOT ENOUGH
+
THERMAL DECOMPOSITION OF CARBONATES
All metal carbonates decompose when heated to form carbon dioxide and a
metal oxide. The process is known as THERMAL DECOMPOSITION
calcium carbonate
—>
calcium oxide
copper carbonate
—>
copper oxide
magnesium carbonate
—>
magnesium oxide
sodium carbonate *
—>
sodium oxide
+
zinc carbonate
—>
zinc oxide
carbon dioxide
+
+
+
carbon dioxide
carbon dioxide
+
carbon dioxide
carbon dioxide
* THE THERMAL DECOMPOSITION OF GROUP I METAL CARBONATES
(SUCH AS SODIUM CARBONATE) REQUIRES A TREMENDOUS AMOUNT OF ENERGY
– A BUNSEN BURNER IS NOT HOT ENOUGH
THERMAL DECOMPOSITION OF CARBONATES
Write out the chemical equations
+
CaCO3 —> CaO
+
CO2
+
CuCO3 —> CuO
+
CO2
+
MgCO3 —> MgO
+
CO2
+
Na2CO3 —> Na2O
+
CO2
+
ZnCO3 —> ZnO
+
CO2
THERMAL DECOMPOSITION OF CARBONATES
+
CaCO3 —> CaO
+
CO2
+
CuCO3 —> CuO
+
CO2
+
MgCO3 —> MgO +
CO2
+
Na2CO3 —> Na2O +
CO2
+
ZnCO3 —> ZnO
+
CO2
QUICKLIME
Calcium oxide
CaO
Reacts with water to form SLAKED LIME (CALCIUM HYDROXIDE)
calcium oxide + water ——> calcium hydroxide +
CaO
Use
+
H2O ——>
Ca(OH)2
added to soil to make it less acidic
added to lakes which have been polluted by acid rain
HEAT
SLAKED LIME & LIME WATER
Lime water
is a solution of calcium hydroxide in water
it is an alkali
it is used to test for the gas carbon dioxide
(limewater goes ‘cloudy’ if CO2 is present)
calcium hydroxide + carbon dioxide ——> calcium carbonate + water
Ca(OH)2
+
CO2
——>
CaCO3
+
H2O
LIMESTONE CYCLE
CALCIUM CARBONATE (limestone)
AQUEOUS
CALCIUM
HYDROXIDE
(lime water)
CALCIUM
OXIDE
(quicklime)
SOLID CALCIUM HYDROXIDE (slaked lime)
CEMENT, CONCRETE & GLASS
All three rely on limestone for their manufacture
CEMENT
powdered clay
powdered limestone
mix and roast them in a rotary kiln
CEMENT, CONCRETE & GLASS
All three rely on limestone for their manufacture
MORTAR
cement
sand
water
mortar is a ‘thin’ form of concrete used for bricklaying
CEMENT, CONCRETE & GLASS
All three rely on limestone for their manufacture
CONCRETE
cement - bonds aggregate together
sand
powdered rock or chippings
water - makes it easier to work with
- causes a chemical reaction to harden the cement
allow the mixture to dry slowly (set)
you get a very hard solid
it is much stronger than simple cement
CEMENT, CONCRETE & GLASS
All three rely on limestone for their manufacture
CONCRETE
cement - bonds aggregate together
sand
powdered rock or chippings
water - makes it easier to work with
- causes a chemical reaction to harden the cement
You choose the correct mixture for the job you are doing
foundations, driveways
paths
filling cracks, holes
cement (1)
cement (1)
cement (1)
large chippings (4½)
small chippings (3½)
coarse sand (3)
you must not add too much water otherwise it takes ages to dry
don’t let it set too quickly otherwise it cracks
avoid laying concrete when it is frosty - it disintegrates
For plastering walls GYPSUM is used; it is a form of calcium sulphate
CEMENT, CONCRETE & GLASS
All three rely on limestone for their manufacture
GLASS
made by heating a mixture of…
limestone - calcium carbonate
sand - silica
soda - sodium carbonate
+ small amounts of other chemicals can be added to make special glass
REACTION OF ACIDS WITH CARBONATES
All carbonates react with acids to form a salt, carbon dioxide and water.
It is an example of a NEUTRALISATION REACTION
CARBONATE + ACID —> A SALT + CARBON DIOXIDE + WATER
Everyday examples
Bad
Good
- acid rain attacks limestone rocks in the countryside
- monuments and statues are attacked
- carbonates can neutralise excess acid in the stomach
REACTION OF ACIDS WITH CARBONATES
All carbonates react with acids to form a salt, carbon dioxide and water.
It is an example of a NEUTRALISATION REACTION
CARBONATE + ACID —> A SALT + CARBON DIOXIDE + WATER
THE SALT THAT IS FORMED DEPENDS ON…
THE METAL CARBONATE AND THE ACID USED
REACTION OF ACIDS WITH CARBONATES
All carbonates react with acids to form a salt, carbon dioxide and water.
It is an example of a NEUTRALISATION REACTION
CARBONATE + ACID —> A SALT + CARBON DIOXIDE + WATER
THE SALT THAT IS FORMED DEPENDS ON…
THE METAL CARBONATE AND THE ACID USED
HYDROCHLORIC ACID
NITRIC ACID
SULPHURIC ACID
produces
produces
produces
CHLORIDES
NITRATES
SULPHATES
REACTION OF ACIDS WITH CARBONATES
All carbonates react with acids to form a salt, carbon dioxide and water.
It is an example of a NEUTRALISATION REACTION
CARBONATE + ACID —> A SALT + CARBON DIOXIDE + WATER
calcium +
carbonate
hydrochloric
acid
—>
calcium
chloride
+
carbon +
dioxide
water
sodium +
carbonate
sulphuric
acid
—>
sodium
sulphate
+
carbon
dioxide
+
water
copper +
carbonate
nitric
acid
—>
copper
nitrate
+
carbon +
dioxide
water
HYDROCHLORIC ACID
NITRIC ACID
SULPHURIC ACID
produces
produces
produces
CHLORIDES
NITRATES
SULPHATES
REACTION OF ACIDS WITH CARBONATES
All carbonates react with acids to form a salt, carbon dioxide and water.
It is an example of a NEUTRALISATION REACTION
CARBONATE + ACID —> A SALT + CARBON DIOXIDE + WATER
calcium +
carbonate
hydrochloric
acid
—>
calcium
chloride
+
carbon +
dioxide
water
sodium +
carbonate
sulphuric
acid
—>
sodium
sulphate
+
carbon
dioxide
+
water
copper +
carbonate
nitric
acid
—>
copper
nitrate
+
carbon +
dioxide
water
HYDROCHLORIC ACID
NITRIC ACID
SULPHURIC ACID
produces
produces
produces
CHLORIDES
NITRATES
SULPHATES
REACTION OF ACIDS WITH CARBONATES
All carbonates react with acids to form a salt, carbon dioxide and water.
It is an example of a NEUTRALISATION REACTION
CARBONATE + ACID —> A SALT + CARBON DIOXIDE + WATER
calcium +
carbonate
hydrochloric
acid
—>
calcium
chloride
+
carbon +
dioxide
water
sodium +
carbonate
sulphuric
acid
—>
sodium
sulphate
+
carbon
dioxide
+
water
copper +
carbonate
nitric
acid
—>
copper
nitrate
+
carbon +
dioxide
water
HYDROCHLORIC ACID
NITRIC ACID
SULPHURIC ACID
produces
produces
produces
CHLORIDES
NITRATES
SULPHATES
REACTION OF ACIDS WITH CARBONATES
All carbonates react with acids to form a salt, carbon dioxide and water.
It is an example of a NEUTRALISATION REACTION
CARBONATE + ACID —> A SALT + CARBON DIOXIDE + WATER
calcium +
carbonate
hydrochloric
acid
—>
calcium
chloride
+
carbon +
dioxide
water
sodium +
carbonate
sulphuric
acid
—>
sodium
sulphate
+
carbon
dioxide
+
water
copper +
carbonate
nitric
acid
—>
copper
nitrate
+
carbon +
dioxide
water
HYDROCHLORIC ACID
NITRIC ACID
SULPHURIC ACID
produces
produces
produces
CHLORIDES
NITRATES
SULPHATES
REACTION OF ACIDS WITH CARBONATES
All carbonates react with acids to form a salt, carbon dioxide and water.
It is an example of a NEUTRALISATION REACTION
CARBONATE + ACID —> A SALT + CARBON DIOXIDE + WATER
calcium +
carbonate
hydrochloric
acid
—>
calcium
chloride
+
carbon +
dioxide
water
sodium +
carbonate
sulphuric
acid
—>
sodium
sulphate
+
carbon
dioxide
+
water
copper +
carbonate
nitric
acid
—>
copper
nitrate
+
carbon +
dioxide
water
HYDROCHLORIC ACID
NITRIC ACID
SULPHURIC ACID
produces
produces
produces
CHLORIDES
NITRATES
SULPHATES
REACTION OF ACIDS WITH CARBONATES
magnesium
carbonate
+
nitric
acid
—>
hydrochloric —>
acid
zinc
+
carbonate
magnesium
nitrate
+ carbon
dioxide
+
water
zinc
chloride
+
carbon +
dioxide
water
sodium
carbonate
+
nitric
acid
—>
sodium
nitrate
+
carbon +
dioxide
water
zinc
carbonate
+
sulphuric
acid
—>
zinc
sulphate
+
carbon +
dioxide
water
copper
carbonate
+
sulphuric
acid
—>
copper
sulphate
+
carbon +
dioxide
water
potassium + hydrochloric —>
carbonate
acid
potassium
chloride
+
carbon +
dioxide
water
REACTION OF ACIDS WITH CARBONATES
magnesium
carbonate
+
nitric
acid
—>
hydrochloric —>
acid
zinc
+
carbonate
magnesium
nitrate
+ carbon
dioxide
+
water
zinc
chloride
+
carbon +
dioxide
water
sodium
carbonate
+
nitric
acid
—>
sodium
nitrate
+
carbon +
dioxide
water
zinc
carbonate
+
sulphuric
acid
—>
zinc
sulphate
+
carbon +
dioxide
water
copper
carbonate
+
sulphuric
acid
—>
copper
sulphate
+
carbon +
dioxide
water
potassium + hydrochloric —>
carbonate
acid
potassium
chloride
+
carbon +
dioxide
water
AQA C1.2.1
Calcium carbonate - summary
a)
Limestone, mainly composed of the compound calcium carbonate (CaCO3), is
quarried and can be used as a building material.
b)
Calcium carbonate can be decomposed by heating (thermal decomposition) to
make calcium oxide and carbon dioxide.
c)
The carbonates of magnesium, copper, zinc, calcium and sodium decompose on
heating in a similar way to give carbon dioxide and the metal oxide.
Not all carbonates of metals in Group 1 of the periodic table decompose at the
temperatures reached by a Bunsen burner.
d)
Calcium oxide reacts with water to produce calcium hydroxide, which is an
alkali that can be used in the neutralisation of acids.
e)
A solution of calcium hydroxide in water (limewater) reacts with carbon dioxide
to produce calcium carbonate. Limewater is used as a test for carbon dioxide.
Carbon dioxide turns limewater cloudy.
f)
Carbonates (eg Mg, Cu, Zn, Ca, Na) react with acids to produce carbon dioxide,
a salt and water. Limestone is damaged by acid rain.
g)
Limestone is heated with clay to make cement. Cement is mixed with sand to
make mortar and with sand and aggregate to make concrete.
CALCIUM
CARBONATE
THE END
© 2011 JONATHAN HOPTON & KNOCKHARDY PUBLISHING