Air
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- Words: 417
- Pages: 12
Air Composition of dry air. 79% : Nitrogen (4/5) 20% : Oxygen (1/5) 0.03% Carbon dioxide 1% Noble gases (mainly Argon)
Laboratory Preparation of Oxygen 1. Decomposion of hydrogen peroxide using Manganese (IV) oxide as catalyst.
Nature of Air: Mixture: Why? 3.
No fixed composition
4. Properties of air is the properties of the components in air 5. The components in air can be separated by physical means like fractional distillation of liquid air.
Fractional Distillation of liquid air Step 1: Purification Step 2: Compression and Expansion Step 3 : Evaporation
Purification ♦ To remove carbon dioxide ♦ To remove water
Otherwise they may form solid which block cooling pipes.
Compression and Expansion ♦ The air is compressed by passing through
coiled pipes and allow to expand .During expansion internal energy of molecules are lost this cools the gas. ♦ A series of compression and expansion eventually cool the air to –200C
Evaporation ♦ The liquid air is allowed to warm up from
-200C. Nitrogen will evaporate first as boiling point is –196C Oxygen will evaporate next as boiling point is –183C.
Uses of oxygen ♦ ♦
♦
Oxy-acetylene flame is used in welding. : property based on oxygen supports combustion. Steel making: oxygen is passed in molten iron to burn off carbon and sulphur which is found in the ore. Hospital,diving etc. :oxygen is needed in respiration ( C6 H12O6 + 6O26CO2+6H2O + heat)
What is Air Pollutants? ♦ State the main atmospheric pollutants ♦ State the sources ♦ Describe the reactions used in possible solutions
to the problems arising from these pollutants ♦ Discuss the effects of the pollutants on health and environment ♦ Importance of ozone layer and the effects of depletion of ozone layer. ♦ Green house gases (sources) and its effects on global warming and its consequences.
Reactions which produces O2 ♦ Heat nitrates
♦ Heat oxides of metal
below Cu in the reactivities series. Nitratesof ♦ Oxidising agents Ca,Mg,Al,Zn.Fe,Pb,Cu Eg Hydrogen peroxide, Produces NO2 and oxides Potassium formed as residue. Permanganate. All nitrates produce 02
Acidic Oxide SO2 CO2
Neutral Oxide C0 NO
NO2 Oxide of Oxide NonOf nonmetal metal Reacts With Base -Salt
Reacts With neither
Basic Oxide Rust MgO Na2O
Amphoteric oxide
Oxide Oxide of Of metal Metal Zn,Al,Pb Reacts Reacts with With Both acid acids Or base ->Salt
Types of reactions involving O2 ♦ Respiration C6H12O6 +O26CO2+ 6H2O+heat ♦ Combustion Fuels
Solid fuel : Liquid fuel : Gas fuel : ♦ Rusting ♦ Oxidation
Coal Petrol Methane ,Hydrogen,
Laboratory Preparation of Oxygen 1. Decomposion of hydrogen peroxide using Manganese (IV) oxide as catalyst.
Nature of Air: Mixture: Why? 3.
No fixed composition
4. Properties of air is the properties of the components in air 5. The components in air can be separated by physical means like fractional distillation of liquid air.
Fractional Distillation of liquid air Step 1: Purification Step 2: Compression and Expansion Step 3 : Evaporation
Purification ♦ To remove carbon dioxide ♦ To remove water
Otherwise they may form solid which block cooling pipes.
Compression and Expansion ♦ The air is compressed by passing through
coiled pipes and allow to expand .During expansion internal energy of molecules are lost this cools the gas. ♦ A series of compression and expansion eventually cool the air to –200C
Evaporation ♦ The liquid air is allowed to warm up from
-200C. Nitrogen will evaporate first as boiling point is –196C Oxygen will evaporate next as boiling point is –183C.
Uses of oxygen ♦ ♦
♦
Oxy-acetylene flame is used in welding. : property based on oxygen supports combustion. Steel making: oxygen is passed in molten iron to burn off carbon and sulphur which is found in the ore. Hospital,diving etc. :oxygen is needed in respiration ( C6 H12O6 + 6O26CO2+6H2O + heat)
What is Air Pollutants? ♦ State the main atmospheric pollutants ♦ State the sources ♦ Describe the reactions used in possible solutions
to the problems arising from these pollutants ♦ Discuss the effects of the pollutants on health and environment ♦ Importance of ozone layer and the effects of depletion of ozone layer. ♦ Green house gases (sources) and its effects on global warming and its consequences.
Reactions which produces O2 ♦ Heat nitrates
♦ Heat oxides of metal
below Cu in the reactivities series. Nitratesof ♦ Oxidising agents Ca,Mg,Al,Zn.Fe,Pb,Cu Eg Hydrogen peroxide, Produces NO2 and oxides Potassium formed as residue. Permanganate. All nitrates produce 02
Acidic Oxide SO2 CO2
Neutral Oxide C0 NO
NO2 Oxide of Oxide NonOf nonmetal metal Reacts With Base -Salt
Reacts With neither
Basic Oxide Rust MgO Na2O
Amphoteric oxide
Oxide Oxide of Of metal Metal Zn,Al,Pb Reacts Reacts with With Both acid acids Or base ->Salt
Types of reactions involving O2 ♦ Respiration C6H12O6 +O26CO2+ 6H2O+heat ♦ Combustion Fuels
Solid fuel : Liquid fuel : Gas fuel : ♦ Rusting ♦ Oxidation
Coal Petrol Methane ,Hydrogen,
