energy and change Flashcards
heat of reaction (ΔH)
the energy absorbed or released in a chemical
reaction.
exothermic reactions
reactions that release energy.
ΔH < 0
endothermic reactions
reactions that absorb energy.
ΔH > 0
activation energy
the minimum energy needed for a reaction to take place.
activated complex
the unstable transition state from reactants to products.
reaction rate
the change in concentration of reactants or products per unit
time.
catalyst
a substance that increases the rate of a chemical reaction
without itself undergoing a permanent change.
A reversible reaction:
A reaction is reversible when products can be converted
back to reactants and vice versa.
Chemical equilibrium
It is a dynamic equilibrium when the rate of the forward
reaction equals the rate of the reverse reaction.
Le Chatelier’s principle:
When the equilibrium in a closed system is disturbed, the
system will re-instate a new equilibrium by favouring the reaction that will oppose the
disturbance.
acid
proton (H+ ion) donor.
base
proton (H+ ion)
acceptor.
hydrolysis
the reaction of a salt with water
equivalence point of a titration
the point at which the acid/base has
completely reacted with the base/acid.
endpoint of a titration
the point where the indicator changes colour.
