Rates 1 Flashcards
Key aspects of collision theory
For a reaction to be successful, particles must collide with enough energy to react and with the correct orientation.
Definition of Activation Energy
The minimum amount of energy required for a reaction to take place
Definition of Rate of Reaction
The amount of reactant used up, or the amount of product produced, in a given amount of time
Four conditions that affect the rate of reaction
Surface Area (of a solid)
Temperature
Concentration (of a gas or solution)
Presence of a Catalyst
Definition of Catalyst
A substance which speeds up a chemical reaction by lowering the activation energy, remaining unchanged by the reaction
Effect of surface area on rate of reaction
If we increase the surface area of a solid reactant, more reactant particles are exposed to each other, leading to an increase in the frequency of collisions (and hence the frequency of successful collisions).
Effect of temperature on rate of reaction
If we increase the temperature, reactant particles have more kinetic energy so more particles have sufficient energy to react successfully. Therefore the frequency of successful collisions increases.
Definition of concentration
A measure of how many particles are dissolved in a given volume of water (or other solvent)
Effect of concentration on rate of reaction
If we increase the concentration there are more reactant particles in a given volume, so particles collide more frequently. This increases the frequency of successful collisions
Four methods for measuring rate of reaction
- Measure the volume of gas produced over time
- Measure how long it takes for a colour change to occur
- Time how long it takes for a reactant to react away (disappear)
- Record the mass lost from a reaction over time
Exothermic Reaction
Releases energy to the environment
Endothermic Reaction
Absorbs energy from the environment
