20 terms

# AQA Rates of reaction & Equilibrium

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temperature
increases the kinetic energy of the molecules
catalyst
A substance that speeds up a chemical reaction but does not get used up.
stirring
stirring increases the rate at which particles dissolve by increasing the kinetic energy of the sample
concentration
increases the number of collisions between molecules
surface area
increases the surface for the reaction to take place
precipitate
solid product formed by reacting two solutions
activation energy
The minimum energy particles must have to react.
effect of catalysts on rate
These provide an alternative reaction route which has a lower activation energy.
effect of surface area on rate
A larger surface area will allow for more collisions and so increase the rate.
effect of concentration on rate
Increases the number of collisions because there are more reagent particles in the same volume.
exothermic
When energy from a reaction is given out to surrounds.
endothermic
When energy for a reaction is taken in from the surroundings.
chemical reaction
This involves the making and or breaking of chemical bonds.
examples of exothermic reactions
Combustion of Fuels, Corrosion of Metals, Reaction Between Acid and Alkali, Respiration
examples of endothermic reactions
Thermal decomposition, photosynthesis, denaturing an enzyme.
closed system
A system where no substances can get in or out.
dynamic equilibrium
A system where both the forward and reverse reactions are taking place simultaneously and at the same rate.
enzymes
Molecules that act as catalysts in biological systems.
Le Châtelier's principle
If a change is made to the conditions of a system at equilibrium, then the position of the equilibrium moves to oppose that change in conditions.
Rate of reaction equation