C3.2

Cards (13)

Endothermic reaction 
A reaction that takes in energy from the surroundings so the temperature of the surroundings decreases
Exothermic reaction 
A reaction that transfers energy to the surroundings so the temperature of the surroundings increases
Exothermic reactions 
Combustion
Many oxidisation reactions
Neutralisation
Endothermic reactions 
Thermal decomposition
Reaction of citric acid and sodium hydrogencarbonate
Everyday examples of exothermic reactions
Self-heating cans (e.g. for coffee)
Hand warmers
Activation energy 
Minimum amount of energy that particles must have to react
Chemical reactions 
1. Reacting particles collide with each other
2. Reacting particles have sufficient energy
Reaction profile 
Shows the relative energies of reactants and products
Shows the activation energy
Shows the overall energy change of a reaction
The arrow in a reaction profile shows the overall energy change
Activation energy 
The energy needed for a reaction to occur
During a chemical reaction
1. Energy must be taken in to break bonds in the reactants
2. Energy is released when bonds in the products are formed
Energy needed to BREAK bonds 
Greater than energy RELEASED
Energy needed to BREAK bonds 
Less than energy RELEASED