9 Kinetics 0.0 / 5 ? ChemistryKineticsA2/A-levelEdexcel Created by: DaneCreated on: 19-02-20 18:47 Why is the study of the rate of reaction important It helps chemists to control reactions in the laboratory and on a large scale in industry 1 of 29 What is the purpose of the development of new catalysts The aim is to make manufacturing processes more efficient so that they use less energy or produce little or no harmful waste 2 of 29 What is meant by the term chemical kinetics It is the study of the rates of chemical reactions 3 of 29 How did the study of rates of reactions help enviornmental scientists It helped to explain why CFC's and other chemicals are destroying the ozone layer 4 of 29 How is the rate of reaction found By measuring the formation of a product or the rate of removal of a reactant 5 of 29 What is the procedure for finding the rate of reaction It is to measure some property of the reaction mixture such as its volume and see how this property varies with time 6 of 29 What is a useful way of studying the effect of changing the conditions on the rate of reaction It is by finding a way of measuring the rate just after mixing the reactants 7 of 29 What is the general trend of rates of reaction The higher the concentration of the reactants the faster the rate of reaction 8 of 29 What is the general trend of the rate of reaction if the reactants are gaseous The higher the concentration or the pressure the faster the rate of reaction 9 of 29 For a number of chemical reactions what temperature rise is needed to double the rate of reaction 10 degrees celcius 10 of 29 Name some examples of equipment in laboratories which is used to speed up reactions by heating the reactants Bunsen burners, hot plates and hearing mantles 11 of 29 Describe the ability of a catalyst They speed up the rate of a chemical reaction without themselves changing permanently 12 of 29 How does a catalyst work A catalyst works by removing or lowering the barriers preventing reaction, they bring reactants together in a way that makes a reaction more likely 13 of 29 Explain how a catalyst can be selective A catalyst may increase the rate of only one very specific reaction an example being enzymes 14 of 29 Describe the characteristics of a catalyst - Catalysts change the mechanism of reactions but they are not reactants and they do not appear in the overall chemical equation 15 of 29 Secondly - Catalysts can be used over and over again but in practise there is some loss of catalyst 16 of 29 Thirdly - Catalsyts can become contaminated and are hard to recover completely from the products 17 of 29 What is a catalyst A catalyst can spped up the rate of a chemical rection without itself changing into to a different substance 18 of 29 What is a mechanism of a reaction The mechanism of a reaction is a description of a reaction and illustrates the breaking of bonds and the formation of the products 19 of 29 What is meant by the term phase It is one of the three stages of matter 20 of 29 What is a heterogeneous catalyst It is a catalyst which is in a different phase from the reactants 21 of 29 What is one of the targets in the modern chemical industry One of the targets is to develop catalysts that make manufacturing processes more efficient to produce less waste and use less energy 22 of 29 What is the benefit of developing a new catalyst It makes it possible to carry out a reaction at a lower temperature or pressure saving fuel 23 of 29 What is kinetic theory It is a model used to explain the behaviour of gases assuming that molecules in a gas are in rapid random motion and colliding with each other 24 of 29 Name some of the assumptions of the kinetic theory model Gas pressure results from the collision of the molecules with the walls of the container 25 of 29 Secondly There is no loss of energy in the elastic collisions between the molecules and the walls of any container 26 of 29 Thirdly The molecules are so far apart that the volume of the molecules can be neglected in comparison with the total volume of gases 27 of 29 Fourthly The molecules do not attract each other 28 of 29 Fiftly The average kinetic energy of molecules is proportional to their temperature on the kelvin scale 29 of 29
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