The reaction rate for chemical change to occur is the speed at which the chemical reactants disappear and form new products (Brady & Senese, 2009). The reaction rate can be measured by considering the amount of production of new products and the consumption of the chemical reactants per unit of time. The rate of reaction is not similar for all chemical reaction processes and this rate can be affected by different factors. The five factors that affect reaction rate will be discussed in the proceeding sections.
Chemical nature of reactants
The rate of reaction for a chemical change is dependent on the natural chemical composition of the reactants involved in the reaction process (Brady & Sense, 2009). By nature, some reactants undergo changes faster than others when all other environmental conditions are controlled. These reaction processes can be described as inherently fast or slow depending on the chemical nature of the reactants. The chemical nature is defined as the reactant’s ability to lose electrons easily and undergo other changes in its chemical bonds (Brady & Senese, 2009).
Ability of reactants to collide with each other
In order for reactants to undergo transformation, the collision of the particles of all reactants is a prerequisite for the chemical reaction to occur (Brady & Senese, 2009). If the particles of the reactants have fewer opportunities to collide with each other, the reaction rate becomes slow. In line with this, the physical state of the reactants can determine the opportunities for collision of the reactants (Brady & Senese, 2009). For this reason, chemical reactions are best induced when chemicals are in liquid solutions or in gas phases in which the particles are given more opportunities to collide and makes the reaction faster.
The concentration of chemical reactants has a direct relationship with the reaction rate. As mentioned in the previous paragraph, reaction rate is faster when there are more opportunities for particle collision. In the same manner, a more concentrated chemical reactant has more particles that will allow an increased number of collisions within a given space (Brady & Senese, 2009). Thus, reaction rate also speeds up in this condition.
When the temperature increases, the energy and speed of the particles also increase (Brady & Senese, 2009). An increase in energy of the particles will decrease the time needed for particles to start colliding with each other. Similarly, an increase in the speed will result in a higher number of collisions in the particles of involved reactants. For these reasons, chemical reaction rate increases in conditions with a high temperature.
Catalysts are substances that cause acceleration in the rate of chemical reactions (Brady & Senese, 2009). These substances can alter the reaction rate without changing its chemical composition at the end of the chemical process. Their main function is to redirect the energy pathway during chemical reactions, and consequently, initiates a faster time for particles to start colliding with each other.
Chemical reactions occur at different speeds. The reaction rate can be affected by the chemical nature of reactants, collision of reactants, concentration of the reactants, temperature, and availability of catalysts. These factors can either speed up or slow down the reaction rate depending on the conditions for chemical reaction to occur.
Brady, J. E. & Senese, F. (2009). Chemistry: The study of matter and its changes (5th ed.). John Wiley and Sons