In this experiment I shall be investigating how temperature affects the rate of reaction
Rates of reaction
The Factors that affect the rate of reaction are temperature, surface area, concentration, catalysts, light and pressure
Surface area – Surface area is the amount of solid surface that is available for reaction - Only affects solids so this will not affect our experiment
- When the surface area increases the rate of reaction increases as there is more surface area for the particles to work on, thus, there are more collisions per second
- Example : It is easier to light a fire with small pieces of stick than using large blocks of wood
Concentration - Concentration is the amount of molecules of a substance in a given volume
- Concentration affects solids, gases and liquid so this will affect our experiment - When the concentration increases the rate of reaction increases as there are more molecules present, therefore there are more collisions between molecules (Collision theory) - Example : zinc reacts fairly slowly with dilute hydrochloric acid but when the acid is concentrated, the rate of reaction increases.
Catalysts - A catalyst is a substance which speeds up the rate of reaction without itself going undergoing any permanent chemical change – this means only small amounts of catalysts are needed to speed up reactions
- When a catalyst is involved in an experiment there is less energy needed for the reaction therefore there is more collisions per second - We will not be using catalysts in our experiment - Example : Decomposing hydrogen peroxide
solution at room temperature is very slow, but using a small amount of manganese oxide greatly increases the reaction rate and oxygen is given off rapidly
Light - Light is a form of energy and it causes many chemical reactions to take place.
- Light does not affect our experiment
- Example : Photosynthesis
Collision theory is used to explain how different factors affect the rate of a chemical reaction. For a reaction to take place the reactant particles must collide with each other with adequate energy (activation energy), this energy is used to break the bonds between the particles. If the particles do not have enough energy they will bounce off each other without reacting. By increasing the temperature the particles gain more energy and move faster causing more collisions per second.
These previous experiments give us background information on rates of reaction:
Acid and limestone
CaCO3(s) + 2HCL(aq) CaCl2(aq) + H2O(l) + CO2(g)
Apparatus – Conical flask, hydrochloric acid, marble chips, cotton wool and scales
In this experiment we mix a certain mass of large marble chips with a certain volume of hydrochloric acid in a conical flask and use cotton wool to trap the acid spray. As the...