rate of reaction?

Question

what are the factors that effect the rate of reaction?
How does concentration effect the rate of reaction?

Answer 1

Temperature: Conducting a reaction at a higher temperature puts more energy into the system and increases the reaction rate. The influence of temperature is described by the Arrhenius equation, whose result is factored into the equation by k. As a rule of thumb, the reaction rate doubles for every 10 degrees Celsius increase in temperature.

Concentration: As reactant concentration increases, the frequency of collision increases and so therefore does the frequency of collisions having sufficient energy to cause reaction.

Pressure: The rate of gaseous reactions usually increases with an increase in pressure. Increase in pressure in fact is equivalent to an increase in concentration of the gas.

Light: Light is a form of energy. It may affect the rate or even course of a reaction. For example when methane reacts with chlorine in the dark, the reaction rate is very low. It can be sped up when the mixture is put under diffused light. In bright sunlight, the reaction is explosive.

Order: The order of the reaction has a major effect on its rate. The order of a reaction is found experimentally, and, for most basic reactions, is an integer value.

A catalyst: The presence of a catalyst increases the reaction rate in both the forward and reverse reactions by providing an alternative pathway with a lower activation energy.
The nature of the reactants: If a reaction involves the breaking and reforming of bonds (complex) compared to just the forming of bonds (simple) then it generally takes longer. The reactants position in the reactivity series also affects reaction rate.

Surface Area: In reactions on surfaces, which take place during heterogeneous catalysis, the rate of reaction increases as the surface area does. The larger the surface area compared to the volume, the faster a reaction can take place, as more simultaneous reactions can occur

Answer 2

Temperature
Concentrations of reactants
Catalysts
Surface area of a solid reactant
Pressure of gaseous reactants or products


Increasing the concentration of the reactants will increase the frequency of collisions between the two reactants. So this is collision theory again. You also need to discuss kinetic theory in an experiment where you vary the concentration. Although you keep the temperature constant, kinetic theory is relevant. This is because the molecules in the reaction mixture have a range of energy levels. When collisions occur, they do not always result in a reaction. If the two colliding molecules have sufficient energy they will react.

If reaction is between a substance in solution and a solid, you just vary the concentration of the solution. The experiment is straightforward. If the reaction is between two solutions, you have a slight problem. Do you vary the concentration of one of the reactants or vary the concentration of both? You might find that the rate of reaction is limited by the concentration of the weaker solution, and increasing the concentration of the other makes no difference. What you need to do is fix the concentration of one of the reactants to excess. Now you can increase the concentration of the other solution to produce an increase in the rate of the reaction.

Answer 3

there are several factors which can effect the rate of a chemical reaction, the temperature, air pressure, surface area and concentration.
from the collision theory, it suggets that increased concentration will increase the rate of reaction because a higher concentration means more number of reactatn's molecules in a fixed space, this will then increase their chance of collision. in order for a chemical reaction to occur the reactants must come to contact first, thus increased concentration will increase the rate of reaction, however, increased concentration will not change the equilibrium constant which i will meantion in the next chapter. ^^

Answer 4

reaction cost shows the cost that reactants flow to products and reaction time shows the time it takes. reaction time and reaction cost are inversely proportional, and whilst the cost will improve, the time decreases.

Answer 5

I concurr with Dangerous Mindz.

Answer 6

light a candle then put your hand over the flame and try to convince your mind that the flame does not exsist then you tell me the answer!