Chaper 5

Transfer thermal energy to the surroundings leading to an increase in temperature of the surroundings

Takes in thermal energy from surroundings leading to a decrease in temperature of the surroundings

Endothermic process -> energy must be supplied to break existing bonds - Overall enthapy change: positive -> energy used to break bonds is greater than energy released by forming them

Exothermic process -> energy is released when new bonds are formed - Overall enthapy change: is negative -> energy released by forming bonds is greater than energy used to break them

Overall amount of energy given out or taken in during a reaction

Combustion - Reacting with oxygen Hand warmers Self-heating cans Neutralisation - When acid reacts with alkali

Sports injury packs Thermal decomposition reactions - Adding heat to make a chemical compound Photosynthesis

The energy required for a reaction to occur - For a reaction to occur, particles need to collide with sufficient amount of energy. The minimum energy required to particles to react upon collision is the activation energy

• Exothermic reactions TRANSFER ENERGY to the surroundings -> so the product molecules have less energy than the reactions • The minimum energy needed for the reaction to start “ Activation energy “

• Endothermic reactions take in energy from the surroundings -> so the product molecules have more energy than the reactants • The minimum energy for the reaction to start is called the “ activation energy “