exothermic and endothermic reactions Flashcards
Energy is ________ in chemical reactions.
conserved
what is an exothermic reaction?
transfers energy to the surroundings so the temperature of the surroundings increases.
examples of exothermic reactions
combustion, many oxidation reactions and neutralisation.
examples of everyday uses of exothermic reactions
self -heating cans and hand warmers.
what is an endothermic reaction?
takes energy in from the surroundings so the temperature of the surroundings decreases.
examples of endothermic reactions
thermal decompositions and the reaction of citric acid and sodium hydrogen carbonate.
example of an everyday use of endothermic reaction
a sports injury pack.
what is the activation energy?
the energy needed for a reaction to occur.
On a reaction profile, what is the activation energy shown as?
shown as the distance from the energy of the reactants to the top of the curved line showing the energy.
On a reaction profile, if the reactants have more energy than the products what does this mean?
then energy has been released and the reaction is exothermic.
On a reaction profile, if the products have more energy than the reactants what does this mean?
then energy has been taken in and the reaction is endothermic.
to break bonds what is needed?
energy
what is released as bonds are made?
energy
In an __________ reaction, the energy ________ from forming new bonds is _______ than the energy needed to break existing bonds.
In an exothermic reaction, the energy released from forming new bonds is greater than the energy needed to break existing bonds.
In an __________ reaction, the energy ______ to break existing bonds is _______ than the energy released from forming new bonds.
In an endothermic reaction, the energy needed to break existing bonds is greater
than the energy released from forming new bonds.
