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lesson on exo and endo reactions
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Exothermic and Exothermic and Endothermic Endothermic
ReactionsReactions
Learning OutcomesLearning Outcomes Describe the term Describe the term exothermicexothermic as a process as a process
or chemical reaction which transfers energy, or chemical reaction which transfers energy, often in the form of heat, to the surroundings often in the form of heat, to the surroundings and may be detected by an increase in and may be detected by an increase in temperature, eg the reaction between temperature, eg the reaction between sodium hydroxide and hydrochloric acid.sodium hydroxide and hydrochloric acid.
Describe the term Describe the term endothermicendothermic as a process as a process or chemical reaction which transfers energy, or chemical reaction which transfers energy, often in the form of heat, from the often in the form of heat, from the surroundings and may be detected by an surroundings and may be detected by an decrease in temperature, eg the dissolving of decrease in temperature, eg the dissolving of ammonium nitrate in water.ammonium nitrate in water.
ExothermicExothermic Process Process or or chemical reactionchemical reaction which which
transfers energy, often in the form of heat, transfers energy, often in the form of heat, toto the surroundings. the surroundings.
May be detected by an May be detected by an increaseincrease in in temperature.temperature.
eg. reaction between eg. reaction between sodium hydroxidesodium hydroxide and and hydrochloric acidhydrochloric acid..
ExamplesExamples
2Mg +O2Mg +O2 2 2MgO 2MgO
Zn + CuSOZn + CuSO44 ZnSO ZnSO44 + Cu + Cu
NN22 + 3H + 3H22 2NH 2NH33
HCHCll + NaOH NaC + NaOH NaCll + H + H22OO
CaCOCaCO33 + 2HC + 2HCll CaC CaCll 22 + + HH22O + COO + CO22
Useful Exothermic Useful Exothermic ReactionsReactions
combustion of fuels
Air bags in cars
self heating cans
Hand warmers
EndothermicEndothermic Process Process or or chemical reactionchemical reaction which transfers which transfers
energy, often in the form of heat, energy, often in the form of heat, fromfrom the the surroundings. surroundings.
May be detected by an May be detected by an decreasedecrease in in temperature.temperature.
eg. the eg. the dissolvingdissolving of of ammonium nitrate in ammonium nitrate in waterwater..
ExamplesExamples
CaCOCaCO33 CaO + CO CaO + CO22
HH22 + I + I22 2HI 2HI
NN22 + O + O22 2NO 2NO
mixing of solids ammonium mixing of solids ammonium thiocyanatethiocyanate and Barium hydroxide and Barium hydroxide
Useful Endothermic Useful Endothermic ReactionsReactions
photosynthesis
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