Endothermic and Exothermic Reactions
Exothermic & Endothermic
Exothermic Reactions An exothermic reaction is one which releases heat energy to the surroundings Temperature increases Hot
Exothermic Reactions Examples include: Burning of fuels. Explosives. Reaction of acids with metals. Magnesium reacting with acid Thermit reaction
Charcoal burning A candle burning. A kettle boiling Ice melting Activity Say whether these processes are exothermic. Charcoal burning A candle burning. A kettle boiling Ice melting A firework exploding yes yes no no yes You have to put heat in for boiling and melting. You get heat out from all the other processes
Exothermic Reactions Magnesium + Hydrochloric acid 25o C 45o C Heat energy given out Gets hot Hydrochloric acid
Endothermic Reactions An endothermic reaction is one which takes in heat energy from the surroundings Temperature decreases Cold
Endothermic Reactions Endothermic reactions cause a decrease in temperature. Endothermic chemical reactions are relatively rare. A few reactions that give off gases are highly endothermic - get very cold. Dissolving salts in water is another process that is often endothermic.
Endothermic Reactions Endothermic reactions cause a decrease in temperature. Ammonium nitrate Water Heat energy taken in as the mixture returns back to room temp. Cools Starts 25°C Cools to 5°C Returns to 25°C
Endothermic and exothermic reactions Step 1: Energy must be SUPPLIED to break bonds: Step 2: Energy is RELEASED when new bonds are made: A reaction is EXOTHERMIC if more energy is RELEASED then SUPPLIED. If more energy is SUPPLIED then is RELEASED then the reaction is ENDOTHERMIC