Rate of reactions

• The combustion of hydrocarbons is exothermic, meaning heat it given out and the temperature in the surrounding rises.
• Breaking chemical bonds is and endothermic reaction.
• Making bonds is an exothermic reaction.
• Fossil fuels are easy to ignite/burn and they are capable of releasing large amounts of energy as heat.
• Endothermic reactions are less common than exothermic ones.
• The reaction between nitrogen and oxygen is exothermic.
• The heat of combustion is the energy change of a reaction when a substance is burnt.
• Polystyrene cups are good insulators.
• Polystyrene cups are used to measure the temp rise in exothermic reactions between solutions.
• When fuels are burnt, energy is needed to ignite them. This is called the activation energy.
• All reactions require activation energy.
• The things that affect reaction rates are: temperature, surface area, concentration, catalysts, and light.
• The rate of reaction increases when the surface area of a solid reactant is increased.
• The rate of a reaction increases when the concentration of a reactant in a solution increases.
• The rate of a reaction increases when the temperature increases.
• A small amount of catalyst can produce a large change in the rate of a reaction.
• If solid pieces have more surface area and are smaller, it increases the frequency of collisions.
• A more concentrated solution means that there are more particles per unit of volume. This increases the collision frequency rate.
• When the temperature is raised, the particles move faster, increasing the rate of collision.
• The more collisions, the faster the reaction.
• A catalyst increases the rate of reaction by reducing the amount of activation energy needed for the reaction and increasing frequency of collisions.