Investigation into how to measure the rate of a chemical reaction and :: GCSE Chemistry Coursework Investigation

Investigation into how to measure the rate of a chemical reaction and how to change the rate of a reaction. Investigation into how to measure the rate of a chemical reaction and how to change the rate of a reaction My task is to produce a piece of coursework investigating rates of reaction, and the effect different changes have on them. The rate of reaction is the rate of the loss of a reactant or the rate of formation of a product during a chemical reaction. There are five factors which affect the rate of reaction according to the collision theory of reacting particles: temperature, concentration (of solution), pressure (in gases), surface area (of solid reactants) and catalysts. I have chosen to investigate the effect of temperature and concentration on a reaction. This is because it is the most practical to investigate. I am investigating the chemical reaction of two substances. The substances being; Sodium thiosulphate and Hydrochloric acid. As a word equation this is: NaSO + 2HCl ----------------> 2NaCl + HO + SO + S sodium + hydrochloric -------------> sodium + water + sulphur + sulphur thiosulphate acid chloride dioxide When these two solutions are mixed together, the mixture gradually goes cloudy, because sulphur is made. I am going to carry out the experiment of changing the temperature (whilst everything else remains constant). My starting temperature will be room temperature because it tends to be constant and it is more practical and will not need to be monitored. When the temperature is varied a water bath will be used to heat up the acid and thiosulphate to the necessary temperature. Prediction According to the kinetic theory all matter is made up of tiny, invisible particles that move all the time. When the temperature is increased around or on these particles, the faster they move. Heavier particles move more slowly than light ones at a given temperature. This theory defines the difference between solids, liquids and gases; in a gas the particles move freely and at random in all the space available. In solids, particles only vibrate around fixed positions and in liquids the particles have some freedom and can move around each other. Using the kinetic theory we can explain changes in state of substances as they are heated and cooled. The kinetic theory can most importantly be used to explain the factors affecting rate of reaction, this is called the Collision theory. The collision theory explains that chemical reactions occur when particles of the reactants collide. Molecules obey Newton's Laws of motion. They undergo elastic collisions with other molecules and the walls, but otherwise exert no forces on each other.