The reaction rate

The reaction rate or speed of reaction specifies the number of chemical reactions taking place per unit time. The reaction rate expressed molarity of solute in reaction generated reaction per second. Perkaratan iron is an example of a slow chemical reaction, while the explosion of gunpowder or fireworks is an example of a rapid reaction.
The rate of the reaction studied by the branch of chemistry called chemical kinetics.A formal definition
For a chemical reaction
aA + bB \ rarr pP + qq
with a, b, p, and q is the coefficient of the reaction, and A, B, P, and Q are substances involved in the reaction, the reaction rate in a closed system is

    v = - \ frac {1} {a} \ frac {d [A]} {dt} = - \ frac {1} {b} \ frac {d [B]} {dt} = \ frac {1} { p} \ frac {d [P]} {dt} = \ frac {1} {q} \ frac {d [Q]} {dt}
where [A], [B], [P], and [Q] states the concentration of such substances.Factors that affect reaction rates
The reaction rate is influenced by several factors, among others:The surface area of ​​the touch
The surface area of ​​the touch has a very important role in many, resulting in faster reaction rates. Likewise, if the smaller surface area of ​​the touch, the smaller inter-particle collisions that occur, so that the reaction rate was smaller. The characteristics of the treated pieces were also influential, namely the more subtle pieces, then the less time it takes to react, while the coarse pieces, then the longer it takes to react.Temperature
Temperature also played a role in affecting the rate of reaction. If the temperature in a reaction that berlangusng raised, it causes the active particles move so collisions are more frequent, causing the reaction rate increases. Conversely, if the temperature is lowered, the particles grew more active, so the smaller the rate of the reaction.Catalytic
A catalyst is a substance that accelerates the rate of a chemical reaction at a certain temperature, without changing or unused by the reaction itself. A catalyst role in the reaction but not as a reactant or product. The catalyst allows the reaction go faster or enable the reaction at lower temperatures due to the changes that triggered the reagent. Catalysts provide a pathway option with a lower activation energy. The catalyst reduces the energy required for the reaction.
The catalyst can be divided into two main groups: homogeneous catalysts and heterogeneous catalysts. The catalyst is a heterogeneous catalyst is in a different phase to the reactants in the reaction dikatalisinya, whereas homogeneous catalysts are in the same phase. One simple example of heterogeneous catalysis is that the catalyst provides a surface on which the reactants (or substrates) temporarily trapped. Bond in the substrates to be weak enough so that the formation of new products. Bond only between the product and the catalyst are weaker, and eventually released.
Homogeneous Catalysts generally react with one or more reactants to form a perantarakimia which then react to form the final reaction product, in a process to recover the catalyst. Here's a common scheme catalytic reactions, where C represents the catalyst:

    A + C \ rarr AC ... (1)
    B + AC \ rarr AB + C ... (2)
Although the catalyst (C) consumed by reaction 1, but then produced again by reaction 2, so for the overall reaction being:

    A + B + C \ rarr AB + C
Several catalysts have been developed which include Ziegler-Natta catalysts are used for the mass production of polyethylene and polypropylene. Catalytic reaction of the best known is the Haber process, which is the synthesis of ammonia using iron as a catalyst usual. Catalytic converter which can destroy the product emission vehicles most difficult to overcome, is made of platinum and rhodium.Molarity
Molarity is the number of moles of solute per unit volume of solvent. His relationship with the rate of the reaction is that the greater the molarity of a substance is, the faster the reaction. Thus at low molarity of a reaction will run slower than a high molarity.Concentration
Because the reaction rate equation is defined in the form konsentrsi with increasing concentrations of the reactants then it also speeds up the reaction. This means that the higher the concentration, the more available reactant molecules collide thus the more likely that the reaction rate also increased.Reaction rate equation
For a chemical reaction
aA + bB \ rarr pP + qq
relationship between the reaction rate is molarity

    \, V = k [A] ^ {n} [B] ^ {m}
with:

    V = rate of reaction
    k = reaction rate constant
    m = Order of reaction of substances A
    n = Order of reaction substance B
Order of reaction substance A and substance B can only be determined through experiments.