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Factors Affecting Reaction SpeedSeveral factors affect the speed of the reaction include the concentration, the nature of the reacting substances, temperature and catalyst.
A. CONCENTRATION
From various experiments showed that the greater the concentration of substances that react faster the reaction takes place. The greater the concentration of more and more substances that react so makinbesar possibility of collision thus the greater the likelihood of reactions.


B. NATURE OF THE SUBSTANCE OF THE REACT
The nature of a substance reacting easy difficulty will determine the speed of the reaction.
In general, it is stated that:-
The reaction between ionic compounds generally take place quickly.This is caused by the presence of attractive forces between the ion-ion opposite.
Example: Ca2 + (aq) + CO32 + (aq) ® CaCO3 (s)This reaction takes place quickly.

 - The reaction between covalent compounds are generally slow.This is due to the reaction is the energy required to break the covalent bonds found in molecules reacting substances.
Example: CH4 (g) + Cl2 (g) ® CH3Cl (g) + HCl (g)This reaction is slow reaction could be accelerated if the energy as the sun.


C. TEMPERATURE
In general, the reaction will go faster when the temperature is raised. With increasing temperature, the kinetic energy of the molecules of a substance that reacts to rise so that more molecules have energy equal to or greater than Ea. Thus, more molecules can reach a state of transition or in other words, the reaction rate becomes larger. Mathematically the relationship between the values ​​of the reaction rate constant (k) with respect to temperature is expressed by the Arrhenius formulation:
k = A. e-E/RT
where:
k: reaction rate constantA: Arrhenius constant of the typical cost for each reactionE: activation energyR: universal gas constant = 0.0821.atm/moloK = 8314 joules / moloKQ: reaction temperature (oK)


D. Catalyst
The catalyst is a substance added to a reaction with a view to enlarge the reaction rate. Catalysts are sometimes involved in the reaction but did not undergo a permanent chemical change, in other words at the end of the reaction the catalyst will be found back in shape and the same amount as before the reaction.
The function of the catalyst is to increase the reaction velocity (speed of reaction) to reduce the activation energy of a reaction and the formation stages of a new reaction. By decreasing the activation energy at the same temperature the reaction can take place more quickly.