The four basic parameters that influence reaction rate are reactant concentration, the physical condition of the reactants, surface area, temperature, and the presence of a catalyst. If you change any one of these factors, then you can expect the reaction rate to change.
In general, higher temperatures mean faster reactions, but there is a limit to how high you can go before you start damaging the chemicals involved. Colder temperatures means slower reactions, but there is no way around this limitation. Also, higher concentrations of reactants will always lead to faster reactions.
Physical conditions such as pressure or vacuum will also influence reaction rates. As pressure increases, so does the likelihood that molecules will collide with each other more often and thus find an alternative path through the molecule list that doesn't involve reacting. A vacuum will work in the opposite direction by increasing the probability that molecules will stay near their original position instead of colliding with others particles.
Surfaces play an important role in reaction dynamics. Reactants will tend to stick to surfaces like glue, preventing them from participating in the reaction. This is why cleaning your reactor vessel inside out with ethanol or similar products will help remove any products that may have formed on its interior surface.
The following elements influence reaction rates:
Reactions occur when two reactant molecules collide with the least amount of energy and in the proper direction. If any one of these factors is changed, then the reaction will proceed at a different rate.
The rate of a chemical reaction can only be determined by experiment. You cannot predict how fast a reaction will go based on knowledge of its components because many other factors are involved. For example, two compounds with the same molecular weight but different structures (bases vs acids) would be expected to react with water under similar conditions at about the same rate because they have equal numbers of electrons in their valence shells. However, experiments have shown that this is not always the case; some bases hydrolyze faster than others do. This difference in reaction rates can be explained by considering the type of bond that exists between each base and water. Hydrogen bonds are much stronger than ionic bonds so it takes more energy to break them. This means that bases with strong hydrogen bonds like ammonia and uric acid will react faster with water than bases like tyrosine which have weak ionic bonds.
Acids also have weaker hydrogen bonds than bases so they will react faster with water.
The chemical reactions that occur in a solution are influenced by the concentration of reactants, temperature, the physical state of reactants and their dispersion, the solvent, and the presence of a catalyst. All these factors play important roles in determining the rate at which a reaction will take place.
In general, the faster the reaction, the greater the influence of each of the factors listed above. However, there are some reactions where some factors have a much more significant effect than others. For example, two molecules of water (H2O) can be converted into one molecule of oxygen gas (O2) and one molecule of hydrogen gas (H2), or they can be combined to form one molecule of hydroxide ion (OH-) and one molecule of water. Which of these processes will occur quickly depends on the concentration of water relative to oxygen and hydrogen gases as well as the temperature of the mixture. At high concentrations of water, gaseous oxygen and hydrogen will be present instead. As we lower the concentration of water, it becomes more likely that we will find itself in a situation where both products are dissolved in water, indicating that oxidation takes place by means of OH- ions.
There are various elements that influence reaction time:
Concentration of the reactant Increasing the concentration of one or more reactants frequently accelerates the reaction. This happens because a higher concentration of a reactant causes more collisions with that reactant in a given time period. These collisions can lead to additional reactions between the reactant and other reactants or products.
Decreasing the concentration of one or more reactants slows down the reaction. This happens because a low concentration of a reactant means that there are fewer collisions with that reactant in a given time period. These collisions can only lead to reactions with other reactants or products.
Changing the location of one or more reactants may also change the rate at which the reaction occurs. For example, if you were to increase the temperature of one or more reactants then this would likely cause the reaction to go faster. This is because at high temperatures, molecules need less time to collide with each other before another collision occurs. Thus, they are involved in many reactions at once.
Decreasing the temperature of one or more reactants would slow down the reaction. At lower temperatures, molecules take longer to collide with each other; therefore, they are involved in fewer reactions per unit of time.
Adding catalysts to a reaction mixture often speeds up the reaction process. A catalyst is a substance that increases the rate of a reaction without being consumed by it.
As the temperature drops, so does the pace of the reaction. Catalysts can reduce activation energy while increasing reaction rate without being spent in the process. Variances in reaction rates can be caused by differences in the intrinsic structures of reactants. Factors such as temperature, pressure, and concentration can all affect the rate of a reaction.