The effects of temperature on the rate of reaction of sodium thiosulphate with hydrochloric acid
Planning
Background
Chemical reactions occur when two or more reactants come into contact with each other. These reactants can produce one or more products and reactions can vary greatly depending on the reactants and the environments which they are in. For example some experiments are exothermic as they produce heat while others are endothermic as they cool their surroundings because they need the heat to react. Some reactions can take place in an unmodified environment e.g. room temperature, normal atmospheric pressure and normal light conditions while others do need these environmental factors changed in order for the experiment to actually happen. These surrounding conditions can also be changed in order to change the rate of reaction. There are other factors that can affect an experiment's rate of reaction and they are concentration, surface area and the presence of a catalyst. Temperature has a very large effect on many reactions. Increasing the temperature of either one or more of the reactants or the temperature in which the reaction is taking place will speed up any reaction.
The increase in rate of reaction is based on the collision theory and activation emery. The collision theory's foundation is the kinetic theory which states that all substances have particles in them that are in a specific shape or form and vibrate or move at a certain speed and it is these particles' form and movement that partly dictate the properties of the material. The different states of matter affect the formation of the particles and their movement.
Fig 1
The collision theory states that for a chemical reaction to occur particles of two or more reactants must collide and this collision must be at or above a certain speed and orientation for the reaction to take place.
It is the speed at which they collide that can be easily changed by varying the temperature because the higher the temperature of the reactant(s) the faster its particles are moving and therefore the higher speed at which a collision may take place.
As stated above, depending on the reactants, there is a speed barrier which must be crossed in order for the reaction to take place. This is the minimum amount of chemical potential energy needed to cause a chemical reaction. This barrier is called activation energy. In order to increase the chemical potential energy stored in the chemical bonds of the reactants they can be heated or be put into a more pressurised environment which changes their kinetic energy. An increase of temperature increases the kinetic energy stored in a reactant therefore increasing the average kinetic energy of particles which results in more collisions causing a reaction. Kinetic energy is the principal source of the chemical potential energy stored in a substance and the chemical potential energy must reach the activation energy level. Once the activation energy level is reached the reactants are automatically converted into the products. The higher the activation energy the slower the rate of reaction and the level of the activation energy depends on the reaction.
Planning
Background
Chemical reactions occur when two or more reactants come into contact with each other. These reactants can produce one or more products and reactions can vary greatly depending on the reactants and the environments which they are in. For example some experiments are exothermic as they produce heat while others are endothermic as they cool their surroundings because they need the heat to react. Some reactions can take place in an unmodified environment e.g. room temperature, normal atmospheric pressure and normal light conditions while others do need these environmental factors changed in order for the experiment to actually happen. These surrounding conditions can also be changed in order to change the rate of reaction. There are other factors that can affect an experiment's rate of reaction and they are concentration, surface area and the presence of a catalyst. Temperature has a very large effect on many reactions. Increasing the temperature of either one or more of the reactants or the temperature in which the reaction is taking place will speed up any reaction.
The increase in rate of reaction is based on the collision theory and activation emery. The collision theory's foundation is the kinetic theory which states that all substances have particles in them that are in a specific shape or form and vibrate or move at a certain speed and it is these particles' form and movement that partly dictate the properties of the material. The different states of matter affect the formation of the particles and their movement.
Fig 1
The collision theory states that for a chemical reaction to occur particles of two or more reactants must collide and this collision must be at or above a certain speed and orientation for the reaction to take place.
It is the speed at which they collide that can be easily changed by varying the temperature because the higher the temperature of the reactant(s) the faster its particles are moving and therefore the higher speed at which a collision may take place.
As stated above, depending on the reactants, there is a speed barrier which must be crossed in order for the reaction to take place. This is the minimum amount of chemical potential energy needed to cause a chemical reaction. This barrier is called activation energy. In order to increase the chemical potential energy stored in the chemical bonds of the reactants they can be heated or be put into a more pressurised environment which changes their kinetic energy. An increase of temperature increases the kinetic energy stored in a reactant therefore increasing the average kinetic energy of particles which results in more collisions causing a reaction. Kinetic energy is the principal source of the chemical potential energy stored in a substance and the chemical potential energy must reach the activation energy level. Once the activation energy level is reached the reactants are automatically converted into the products. The higher the activation energy the slower the rate of reaction and the level of the activation energy depends on the reaction.
