gcaco3pps

7/29/2019 gcaco3pps

1/35

CALCIUM

CARBONATEA guide for GCSE students

KNOCKHARDY PUBLISHING 2010SPECIFICATIONS

7/29/2019 gcaco3pps

2/35

CALCIUM CARBONATE

INTRODUCTIONThis Powerpo in t 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.

7/29/2019 gcaco3pps

3/35

LIMESTONELimestone is made of calcium carbonate CaCO3

Origin Formed in the sea millions of years agofrom 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

7/29/2019 gcaco3pps

4/35

LIMESTONE PRODUCTS ARE VERY USEFUL

GLASS

CONCRETE

CEMENT / MORTAR

especially in building houses

7/29/2019 gcaco3pps

5/35

CARBONATESFormulae All carbonates contain the CO3 unit

The compounds are ionic; the formula is found bybalancing the charges of the ions

Carbonate ions have a 2- charge CO32-

CALCIUM CARBONATE

CaCO3

SODIUM CARBONATE

Na2CO3

7/29/2019 gcaco3pps

6/35


The compounds are ionic; the formula is found bybalancing the charges of the ions

Carbonate ions have a 2- charge CO32-

CALCIUM CARBONATE

CaCO3

SODIUM CARBONATE

Na2CO3

7/29/2019 gcaco3pps

7/35


Chemical

formula

sodium carbonate Na2CO3

calcium carbonate CaCO3

magnesium carbonate MgCO3

copper carbonate CuCO3

7/29/2019 gcaco3pps

8/35


Chemical

formula

sodium carbonate Na2CO3

calcium carbonate CaCO3

magnesium carbonate MgCO3

copper carbonate CuCO3

7/29/2019 gcaco3pps

9/35

PROCESSING LIMESTONERoasting Heating limestone very strongly makes it break up

The process is known as THERMAL DECOMPOSITION

calcium carbonate > calcium oxide + carbon dioxide

CaCO3 > CaO + CO2

Calcium oxide is also known as QUICKLIME

7/29/2019 gcaco3pps

10/35

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.

Test any gas with the limewater.

Appearance CO2 produced

Calcium carbonate

CaCO3

Copper carbonate

CuCO3

Magnesium carbonate

MgCO3

Zinc carbonate

ZnCO3

Residue Conclusion

metal

carbonate

lime water

CO2

7/29/2019 gcaco3pps

11/35

ACTION OF HEAT ON METAL CARBONATES

WHITE

SOLID

Appearance CO2 produced

Calcium

carbonate

CaCO3Copper

carbonate

CuCO3

Magnesium

carbonate

MgCO3

Sodium carbonate (Na2CO3) also decomposes on heating but it requires more heat

than an ordinary bunsen burner can supply.

Zinc

carbonate

ZnCO3

WHITE

SOLID

Calcium oxide

formed (needs verystrong heating)

BLACK

SOLIDCopper oxide

formed

WHITE

SOLIDMagnesium oxide

formed

YELLOW SOLID

WHICH TURNS

WHITE WHEN COOL

GREEN

SOLID WHITE

SOLID

WHITE

SOLID

Residue Conclusion

Zinc oxide

formed

7/29/2019 gcaco3pps

12/35

THERMAL DECOMPOSITION OF CARBONATESAll metal carbonatesdecompose when heated to form carbon dioxide and a

metal oxide. The process is known as THERMAL DECOMPOSITION


copper carbonate > copper oxide + carbon dioxide

magnesium carbonate > magnesium oxide + carbon dioxide

sodium carbonate * > sodium oxide + carbon dioxide

zinc carbonate > zinc oxide + 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

+

7/29/2019 gcaco3pps

13/35

THERMAL DECOMPOSITION OF CARBONATESAll metal carbonatesdecompose when heated to form carbon dioxide and a

metal oxide. The process is known as THERMAL DECOMPOSITION


copper carbonate > copper oxide + carbon dioxide

magnesium carbonate > magnesium oxide + carbon dioxide

sodium carbonate * > sodium oxide + carbon dioxide

zinc carbonate > zinc oxide + 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

7/29/2019 gcaco3pps

14/35

THERMAL DECOMPOSITION OF CARBONATESCaCO3 > CaO + CO2

CuCO3> CuO + CO2

MgCO3> MgO + CO2

Na2CO3> Na2O + CO2

ZnCO3 > ZnO + CO2

+

+

+

+

+

Write out the chemical equations

7/29/2019 gcaco3pps

15/35

THERMAL DECOMPOSITION OF CARBONATESCaCO3 > CaO + CO2

CuCO3> CuO + CO2

MgCO3 > MgO + CO2

Na2CO3> Na2O + CO2

ZnCO3 > ZnO + CO2

+

+

+

+

+

7/29/2019 gcaco3pps

16/35

QUICKLIMECalcium oxide CaO

Reacts with water to form SLAKED LIME (CALCIUM HYDROXIDE)

calcium oxide + water > calcium hydroxide + HEAT

CaO + H2O > Ca(OH)2

Use added to soil to make it less acidicadded to lakes which have been polluted by acid rain

7/29/2019 gcaco3pps

17/35

SLAKED LIME & LIME WATERLime 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

7/29/2019 gcaco3pps

18/35

LIMESTONE CYCLE

AQUEOUS

CALCIUM

HYDROXIDE

(lime water)

SOLID CALCIUM HYDROXIDE (slaked lime)

CALCIUM CARBONATE (limestone)

CALCIUM

OXIDE

(quicklime)

7/29/2019 gcaco3pps

19/35

CEMENT, CONCRETE & GLASSAll three rely on limestone for their manufacture

CEMENT powdered clay

powdered limestone

mix and roast them in a rotary kiln

7/29/2019 gcaco3pps

20/35


MORTAR cement

sand

water

mortar is a thin form of concrete used for bricklaying

7/29/2019 gcaco3pps

21/35


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

7/29/2019 gcaco3pps

22/35


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 cement (1) large chippings (4)

paths cement (1) small chippings (3)

filling cracks, holes cement (1) coarse sand (3)

you must not add too much water otherwise it takes ages to dry

dont 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

7/29/2019 gcaco3pps

23/35


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

7/29/2019 gcaco3pps

24/35

REACTION OF ACIDS WITH CARBONATESAll carbonatesreact 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 - acid rain attacks limestone rocks in the countryside

- monuments and statues are attacked

Good - carbonates can neutralise excess acid in the stomach

7/29/2019 gcaco3pps

25/35




THE SALT THAT IS FORMED DEPENDS ON

THE METAL CARBONATE AND THE ACID USED

7/29/2019 gcaco3pps

26/35




THE SALT THAT IS FORMED DEPENDS ON

THE METAL CARBONATE AND THE ACID USED

HYDROCHLORIC ACID produces CHLORIDES

NITRIC ACID produces NITRATES

SULPHURIC ACID produces SULPHATES

7/29/2019 gcaco3pps

27/35




calcium + hydrochloric > calcium + carbon + water

carbonate acid chloride dioxide

sodium + sulphuric > sodium + carbon + water

carbonate acid sulphate dioxide

copper + nitric > copper + carbon + water

carbonate acid nitrate dioxide




7/29/2019 gcaco3pps

28/35













7/29/2019 gcaco3pps

29/35













7/29/2019 gcaco3pps

30/35













7/29/2019 gcaco3pps

31/35













7/29/2019 gcaco3pps

32/35

REACTION OF ACIDS WITH CARBONATESmagnesium + nitric > magnesium + carbon + water


zinc + hydrochloric > zinc + carbon + water


sodium + nitric > sodium + carbon + water


zinc + sulphuric > zinc + carbon + water


copper + sulphuric > copper + carbon + water


potassium + hydrochloric > potassium + carbon + water


7/29/2019 gcaco3pps

33/35

REACTION OF ACIDS WITH CARBONATESmagnesium + nitric > magnesium + carbon + water


zinc + hydrochloric > zinc + carbon + water


sodium + nitric > sodium + carbon + water


zinc + sulphuric > zinc + carbon + water


copper + sulphuric > copper + carbon + water


potassium + hydrochloric > potassium + carbon + water


7/29/2019 gcaco3pps

34/35

AQA C1.2.1 Calcium carbonate - summarya) 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.

7/29/2019 gcaco3pps

35/35

CALCIUM

CARBONATETHE END

2011 JONATHAN HOPTON & KNOCKHARDY PUBLISHING

Documents

gcaco3pps