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Whenever chemical reactions occur, energy is transferred to or from the surroundings.
An exothermic reaction is one which transfers heat energy to the surroundings
An endothermic reaction is one which takes heat energy from the surroundings
Exothermic process: a physical or chemical change that releases heat energy
Burning fossil fuels is an exothermic reaction.
reaction
Exothermic Change - heat Exothermic Change - heat is given off and the is given off and the temperature risestemperature rises
Reactants Products
A + B AB
Forming a Chemical Bond - Releases Energy
EXOTHERMIC EXAMPLES
A candle flame
Rusting iron
Burning sugar
Glow sticks
Fire crackers
Some hand warmers
Burning Wood
Freezing Water
Endothermic process: a physical or chemical change that requires (or absorbs) heat
energy
Photosynthesis is an endothermic reaction
(requires energy input from sun)
reaction
Endothermic reaction - Endothermic reaction - heat is taken in and the heat is taken in and the temperature may droptemperature may drop
Reactants Products
AB A + B
Breaking a Chemical Bond - Absorbs Energy
ENDOTHERMIC EXAMPLES
Baking bread
Cooking an egg
Photosynthesis
Melting Ice
Cold packs from nurse