There are four factors that increase the number of collisions of particles in an experiment...
1) Higher Temperature
- At a higher themperature, the particled move more quickly as they have more energy.
- This causes them to collide more frequently.
2) Higher Concentration or Pressure
- If a solution is more concentrated, there are more particles, meaning they are more likely to collide. The same principle works for gases under pressure.
3) Larger Surface Area
- Having a larger surface area means that there is a greater area for the paricles to collide with.
- They increase the number of collisions by lowering the activation energy.
Energy Transfer in Reactions
Bond Breaking ---> Energy must be supplied for the bonds in molecules to break. This means that breaking bonds is endothermic.
Bond Forming ---> Energy is given out from the molecule when a bond is formed, so this process is exothermic.
- In an exothermic reaction, energy is released because more bonds are made than broken.
- The temperature of the surroundings will rise because energy is given out.
- In an endothermic reaction, energy is taken in because the energy needed to break bonds is greater than the energy needed to make them.
- The surrounding temperature will fall because the energy is taken in.
The change in energy is called an enthalpy change and is measured in /\H (kJ/mol).