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Rates of reactions

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RESEARCH: Chemical engineers exploit chemical reactions to produce materials on a commercial scale. One of their principal activities is the design and operation of chemical reactors. In order to accomplish design goals, the engineer often needs to know the kinetics of a reaction -- the factors that influence the rate of the reaction. In what follows, a brief discussion of the basic ideas in chemical kinetics is presented along with the mathematical models used to study the kinetics of chemical reactions. The close resemblance of the mathematical equations modeling chemical kinetics to those modeling population dynamics will become apparent. Appropriate links to topics in population dynamics will be indicated for you to explore if you so desire. Reaction Rates A chemical reaction involves one or more substances (reactants) that react to produce other substances (products). As the reaction proceeds, some chemical species are depleted while others are formed. Certain laws govern this process, and these laws can be expressed in terms of mathematical equations Balance Laws One of the assumptions made in chemical kinetics is that the number of atoms is preserved, i.e. atoms are neither created nor destroyed. For example, if there are atoms of Oxygen, , present before the reaction begins, then there will be the same number, , of atoms of Oxygen during all stages of the reaction. ...read more.


However if one set of results is entirely different to the other, a third experiment will be performed to replace the anomalous set of results. Safety A pair of goggles will be worn during the heating part of the experiment in order to protect the eyes. An apron will also be worn to protect the skin and clothing. When handling hot beakers and measuring cylinders a pair of tongs will be used. A gauze and heatproof mat will be used while heating to avoid any damage to the equipment. Fair Test In order for my findings to be valid the experiment must be a fair one. I will use the same standard each time for judging when the X has disappeared. I will make sure that the measuring cylinders for the hydrochloric acid and thiosulphate will not be mixed up. The amount of hydrochloric acid will be 5cm each time, and the amount of thiosulphate will be fixed at 50 cm3. During the heating stage of the experiment,a constant temperature will be used throughout. All of these precautions will make my final results more reliable and keep anomalies at a minimum so thus make the entire investigation more successful. Prediction I predict that as the temperature is increased the rate of reaction will increase. ...read more.


and so time would have been lost (or made up) from the time I observe the first changes in the solution to the time I stop the clock. My own human reaction time may have been quicker or slower from experiment to experiment. Another factor that could have been effecting the progress of my experiment was the fact that after taking the conical flask out of the waterbath I did not check the temperature again to make sure bath had maintained its acuracy. Any drop in temperature may have caused a varriation in my results. If I carried out this investigation again I think I would pay more attention to degrees of accuracy, I would also like to investigate the effects of concentration on the rate of a reaction as this would supply a more varried aray of data and may help me to understand different aspects of the 'collision theory'. Although there are aspects that need improving in the experimentation rea of my coursework I am pleased with the overall product I have produced. I believe some aspects of my experiments were sucessful allowing a fairly high degree of accuracy, for instance I always took full care to make sure that the conical flask used was thoroughly cleaned in between each experiment and the area in which I worked was a safe environment, all these factors will help me improve any future investigations I carry out. ...read more.

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