Year 12 Chemistry - Unit One

REVISION POINTS

Chapter 23 – The Earth’s Atmosphere

• Layers of the atmosphere - know the main layers - troposphere, mesosphere, stratosphere, thermosphere, exosphere.
• Main gases that comprise the atmosphere - N₂, O₂, Ar, CO₂, other noble gases, and H₂O_(vap)
• Separation of gases by fractional distillation - have an understanding of how the process works.
• Know some uses of the noble gases.
• Nitrogen - Use of nitrogen in the manufacture of fertilisers, ammonia, nitric acid, explosives; 
• Physical and chemical properties of nitrogen, Industrial preparation of oxygen.Haber process for the preparation of ammonia.Uses of ammonia to make fertilisers and explosives, Nitrogen cycle - be able to explain the function of the denitrifying bacteria, nitrogen fixation.
• Oxygen - Physical and chemical properties of oxygen.Test for oxygen. Laboratory preparation of oxygen.Industrial preparation of oxygen.
• Ozone Discuss the importance of ozone in the upper atmosphere.The chemical reactions for the formation of ozone in the upper atmosphere.The effect os CFCs on ozone.Uses of ozone.
• Carbon dioxide Physical and chemical properties of carbon dioxide.Test for carbon dioxide.Laboratory preparation of carbon dioxide.Industrial preparation of carbon dioxide.
• Carbon monoxide Formation of carbon monoxide by incomplete combustion.Effects of carbon monoxide on animals.
• Carbon cycle.

• Explanation of properties of solids, liquids and gases with respect to volume, attractive forces, density, shape, compressibility, ease of mixing.
• Phase Changes - be able to interpret graphs.
• Be able to define - boiling point, vapour pressure, molar heat of vaporisation and fusion, sublimation.
• Relationship between average K.E. and absolute Temperature.
• Graph of K.E. versus no. of particles; what happens to this curve as T increases?
• Be able to explain vapour pressure and its relationship to b.pt.
• Be able to explain vapour pressure, molar heat of vaporisation/fusion, m.pt, b.pt., as a measure of the strength of the attractive forces.

• Kinetic Theory of Gases - know 5-6 main points; be able to explain behaviour of gases in terms of kinetic theory e.g. ease of mixing, compressibility, variable volume, diffusion of gases, pressure exerted by gas, low density etc.
• Know Boyle’s Law - be able to draw or interpret graphs of Boyle’s Law.
• Be able to do problems involving Boyle’s Law.
• Know Charles’ Law - be able to draw or interpret graphs of Charles’ Law.
• Be able to convert from Celsius to Kelvin and reverse.
• Be able to do problems involving Charles’ Law.
• Know Gay-Lussac’s Law.
• Know Combined Gas Law, general Gas Equation.
• Be able to do problems involving Combined Gas Law and general Gas Equation
• Know relationships between n and V (T,p fixed); Molar volume and Avogadro’s Hypothesis.
• Be able to define Absolute zero, STP, Ideal gas, Real gas.
• Know and be able to use Dalton’s Law of partial pressures particularly where it applies to gases collected over water.
• Be able to do problems involving mass-volume and volume-volume stoichiometry.

• Be able to list some various sources of energy
• Explain the difference between renewable and non-renewable forms of energy
• Be able to list some various forms of energy - heat energy, mechanical energy, sound energy, electrical energy, chemical energy, radiation energy etc.
• Be able to explain what is meant by the heat content or enthalpy of a substance.
• State the law of conservation of energy and be able to explain what is meant by transformations of energy.
• Be able to explain the meaning of the term fossil fuel.
• State the various ranks of coal and be able to explain how they differ in C content, H content, O content, moisture content, volatile content, heating value.
• Be able to list advantages and disadvantages of coal as a fuel
• Be able to explain what is meant by the heating value of coal
• Problems involving the heating value of coal.
• Be able to explain what a bomb calorimeter is
• Discuss the products formed from the combustion of coal and the origin of these products - CO₂, water vapour, SO₂, oxides of nitrogen, ash
• Problems involving calculations of the amount of moisture released, or carbon dioxide released from the combustion of coal.
• Gaseous fuels from coal - coal gas, producer gas and water gas (or SYNGAS)
• Be able to explain how substitute natural gas (methane) can be made from coal; be able to explain the significance
• Be able to explain how liquid fuels can also be made from coal.
• Natural Gas
• Advantages of natural gas
• Be able to explain how methanol can be made from natural gas - how does the shift reaction in this process differ from that used in the manufacture of methane from coal?
• Crude oil
• Be able to write combustion reactions for complete and incomplete combustion.
• Revise the meaning of the terms fractional distillation, catalytic cracking and catalytic reforming.
• Know the meaning of the terms - air:fuel ratio; and lean and rich mixture
• Be able to discuss the pollutants from car exhausts, what causes them and their effect on the environment - carbon monoxide, sulfur dioxide, nitrogen oxides, unburnt hydrocarbons, solid particles.
• Have a very basic understanding of what happens in a simple four stroke engine; the effect of the timing of the spark, compression ratio;
• Know what is meant by the octane rating and the factors that affect it.
• Be able to discuss the effects of the air-fuel ratio on - power, fuel consumption and levels of pollutants;
• Be able to discuss the effect of the type of engine operation (idling, accelerating, decelerating, cruising) on the level of various pollutants emitted.
• Be able to discuss why lead products were added to fuel and why their use has now discontinued. Problems
• Discuss some methods by which pollutant levels in car exhausts are reduced - catalytic converters, exhaust gas re-circulation.