Josh
October 2, 2014 Period 3
Introduction:
In reference to the collision theory, molecules act as small spheres that collide and bounce off each other, transferring energy among themselves when the collide. In order for a reaction to occur, there must be collisions between molecules. Through experimentation, factors are discovered that influence the reaction rates of chemical reactions include the concentration of reactants, temperature, surface area, the physical state of reactants, and a catalyst. This experiment regarding the factors that affect reaction rate tests the effects of increased concentration and temperature of the hydrochloric acid solution (HCl) and also the effect of increased surface area of magnesium metal (Mg). When glow sticks are immersed in a hot water bath, it is proven that they glow with greater intensity. This proves that an increased temperature has an effect on the reaction itself, allowing molecules that make up the liquid inside the glow stick to move with greater speed, resulting in more collisions. The balanced equation for this reaction would be: Mg (s) + 2 HCl (aq) = MgCl2 (aq) + H2 (g)
Purpose:
The objective of this laboratory experiment is to observe and record the effect of reactant concentration, reactant surface area and reactant temperature on the overall rate of reaction.
Hypothesis:
During this experiment, acids of different concentration are utilized, and the different reaction rates calculated. When the reactant’s concentration increases, there are more atoms per space for a collision to occur. A prediction for the effect of concentration on reaction rate would be that the higher the concentration of the reaction, the faster the reaction time. As the temperature of the reaction rate increases, the molecules will move faster, also resulting in more collisions and perhaps a faster reaction rate.
References: Hebden Chemistry 12: Workbook for Students, Unit 1: Reaction Kinetics, pg. 1-36 Heath Chemistry Laboratory Experiments, Experiment 18 A: Factors Affecting Reaction Rate, pages. 192-196 Factors Affecting Reaction Rates http://chemwiki.ucdavis.edu/Physical_Chemistry/Kinetics/Factors_That_Affect_Reaction_Rates This website was used on October 3, 2014 to help develop a better understanding of collision theory in order to explain the various factors affecting the rate of reaction.