Relationship Between Surface Area and Rate Of Reaction Essay -- GCSE C

An Experiment To Investigate The Relationship Between Surface Area and Rate Of Reaction Introduction The rate of reaction (reaction velocity) may be defined as the rate of change of concentration of a stated reactant or product. The rate of a reaction is found by measuring the amount of a reactant used up per unit of time or the amount of a product produced per unit of time. A reaction can be made to go faster or slower by changing a number of factors. In order for a reaction to occur certain things are necessary: particles must collide with each other and the collision must have enough energy for the reaction to occur. If this happens the original bonds are broken and new bonds are formed - so that new products are formed. Successful collisions (those with sufficient energy) can be increased (or decreased) by a number of factors. These key variables consist of temperature, concentration, surface area and use of and type of a catalyst. To examine the relationship between the rate of reaction and surface area I must choose to vary only surface area keeping the other variables constant. Surface area of solid - The surface area has an effect on the rate of reaction. If the solid has a large surface area per unit mass then there are more opportunities for collisions to occur between the solid and liquid. This is because there is more chance for collisions to occur. If the surface area per unit mass is small, collision can only occur with the outer atoms and is therefore limited. The diagram below illustrates this: This relationship is proportional i.e. as one doubles so does the other. The temperature of the reaction - When the temperature is low, the particles in the reaction do not have much energy and move slowly so collision... ...nes which can be explained by the fact that the surface area of the chips was constantly changing throughout the reaction, as it was reacted with the acid, and so did the surface area to volume ratio. Also as the marble was used up the reaction would slow, as there would be less marble remaining to react with the acid reducing the chances of a collision occurring. The evidence is sufficient to imply that my hypothesis is correct but I think to prove it successfully further evidence would be necessary. I could have checked the rates of reactions I produced as a result of my experiment by carrying out a different test. If I had examined my results by doing a test measuring the mass change of the calcium carbonate I could have checked that I came up with sufficiently similar final rates of reaction, however I did not have time for this or to use a wider range of values.