Lab 2 Some Factors Affect Reaction Rate Essay

Words: 1254
Pages: 6

Bingying Jiang
CHM 152ll
April 25, 2013
Some Factors that Affect the Rate of a Reaction
Chemical reactions occur at different rates. In this experiment I will consider some of the key factors that influence the rate of a reaction: *  nature of reactants - particle size *  temperature *  catalysts According to the collision theory, the rate of a reaction depends on the frequency of collisions between reacting particles. The more frequent the collisions, the faster the rate of the reaction. However, in order for the collisions to be effective, the particles must collide with sufficient energy (activation energy). Furthermore, the particles must collide with the proper orientation.
The factors that
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Therefore, the higher the temperature is, the larger the rate of reaction will be. When there is a decrease in temperature the rate of reaction decreases. In this case, the particles will have less energy, which will prevent the particles to move quickly and collide with one another. When the temperature of the water was 35°F it took 120 seconds for the Alka Seltzer tablet to dissolve. While, when the temperature increased to 81°F the reaction took only 33 seconds, and it took only 18 seconds for the tablet to fully dissolve in 150°F water.
In second case, the more surface contact between the reactants, the higher the rate of reaction. The less surface contact, the lower the rate of reaction. When chunks of Alka Seltzer were placed in the water, the surface contact increased, and it only took 25 seconds for the tablet to dissolve. Lastly, the crushed tablet had the most surface area, and dissolved in 18 seconds.
In the last case, a chemical reaction with no catalyst would have a lower rate of chemical reaction, compared to a reaction with a catalyst, since a catalyst is defined as a substance that speeds up the rate of a chemical reaction without being used up in the reaction itself. Catalysts work by lowering the activation energy required for the Alka Seltzer molecules to interact with water and dissolve. NaCl only used 28s, and Vinegar used 30s. The NaCl was more effective in