1) Energy transfer during exothermic and endothermic

• When chemical reactions occur, energy is transferred from the chemicals to or from the surroundings.
• Therefore, many reactions are accompanied by a temperature change.
• Exothermic reactions are accompanied by a temperature rise
• They transfer heat energy from the chemicals to the surroundings, i.e. they give out heat energy.
• Exothermic reactions are used in products like self-heating cans (for coffee) and hand warmers
• .Endothermic reactions are accompanied by a fall in temperature. 
• Some sports injury packs use endothermic reactions.
• If a reverelible reaction is exothermic in one direction, then it is endothermic in the opposite direction. .The same amount of energy is transferred in each case.
• Exothermic reactions are accompanied by a temperature rise. Endothermic reactions are accompanied by a fall in temperature.