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Rates of chemical reactions 6.4 (Temperature: (Increasing temperature =…
Rates of chemical reactions 6.4
Fast and slow chemical reaction
how fast the reaction occurs = rate of reaction
Some reactions are fast and some slow e.g. Explosion of a gas (fast) Rusting (slow)
Controlling the rate of chemical reactions
The rate of almost everything can be increased or deceased e.g. When you heart pumps faster to speed up the rate of respiration, and the opposite.
Factors that affect the rate of reaction are:
Temperature
Concentration of the reaction
Surface area (small or large)
Agitation (mixing/stirring)
Catalysts (chemical helpers)
Temperature:
Increasing temperature = increasing rate of reaction
the particles get more energy colliding harder, breaking the bonds more, then the atoms can rearrange more easily
The heat speeds up particles therefore them bumping into each other more frequently, so more reactions happen
Concentration:
The concentration refers to the amount of substance in a volume of liquid.
The concentration is high if you put 20 tsp of sugar in 1L of water instead of 1tsp
increasing the concentration of the reactant will increase the rate of reaction as the particles are more likely to collide
Surface area:
The smaller the surface area the quicker the reaction will take place, this is because if there was I large surface area it will only react with the outside of it
Agitation:
Stirring/Agitation reactants can also increase the rate of reaction
Agitation makes sure that the reactants are kept in contact
By stirring it flushes away the products that are surrounding the reactants slowing the reaction, so then the can react
Catalysts:
Catalysts are chemicals that speed up the chemical reaction
they reduce the amount of energy that is required to convert the reactants into products
they make it easier for the reactant molecules to combine and form products