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Introduction, Burning candle wax in air.

Answer Text:
WATER AND HYDROGEN.
Introduction:
- Water is the most abundant substances on earth;
- It covers about 71% of the earth’s surface;
- Main sources of water include seas, lakes, rivers, oceans.
Burning candle wax in air.
Apparatus:

Procedure.
- The candle is lit under the funnel and the suction pump turned on.
- The set up is left undisturbed for about 15 minutes.
Observations;
- The candle continues to burn.
- Droplets of a colourless liquid in the tube A;
- The colourless liquid turns white anhydrous copper (II) sulphate to blue and blue anhydrous cobalt (II) chloride into pink;
- A white precipitate forms in the calcium hydroxide in tube B;
- Deposits of a black solid on the inner sides of the funnel;
Explanations;
- The suction pump ensures continuous supply of air hence the candle continues to burn;
- Candle wax buns in oxygen to form carbon (IV) oxide and steam;
- The carbon (IV) oxide is sucked out through the apparatus by the suction pump;
- Carbon (IV) oxide forms a white precipitate of calcium carbonate when bubbled through lime water (calcium hydroxide)
- Incomplete combustion of the carbon in the candle wax produces carbon particles which cools and deposits as black solids;
Equations:
As the candle burns:
Carbon + Oxygen → Carbon (IV) oxide;
#C(s) + O_2(g) → CO_2(g)#;
Hydrogen + Oxygen → water
#2H_2(g) + O_2(g) → 2H_2O(g)#;
For the formation of the black deposits (soot)
Carbon + Oxygen → Carbon
+ Carbon (IV) oxide;
#2C(s) + O_2(g) → C(s) + CO_2(g)#;
In the calcium hydroxide:
Carbon (IV) oxide + calcium hydroxide → Calcium carbonate + Water
Colourless Colourless White precipitate
Colourless
#CO_2(g) + Ca(OH)_2(aq) → CaCO_3(s) + H_2O(l)#;
- The steam condenses into water in the boiling tube;
- Water turns white anhydrous copper (II) sulphate to blue and blue anhydrous cobalt chloride paper into pink;
General equation:
Hydrocarbon + Oxygen →Water + Carbon (IV) oxide;
Conclusion:
- Candle wax is a compound of carbon and hydrogen only; and such compounds are defined as
hydrocarbons;
- When burned in air (oxygen) hydrocarbons produce carbon (IV) oxide and steam (water);
- Other examples of hydrocarbons include: petrol; diesel; kerosene etc;