Chem 230 Lab Exam 1| 72 Questions| With Complete Solutions

What is the purpose of Lab 1: Kinetics correct answer: To examine the four factors that influence the reaction rate of a chemical reaction What conditions influence the rate of reaction of a chemical process? correct answer: 1. Concentration of reactants 2. Temperature 3. Presence of a catalyst 4. Physical state of the reactants (including surface area) What effect did the concentration of reactants have on the reaction rate? What is the reason for the effect? correct answer: - As the concentration of the reactants INCREASES, there are more molecules per unit of volume, thus increasing the chance that an effective collision between molecules will occur What effect did the temperature have on the reaction rate? What is the reason for the effect? correct answer: - Increasing the temperature of a chemical reaction INCREASES the average kinetic energy of the molecules, therefore, the number of collisions with SUFFICIENT ENERGY to cause a reaction to occur will also INCREASE. What effect did the catalyst have on the reaction rate? What is the reason for the effect? correct answer: - A catalyst will speed up the chemical reaction BUT it WILL NOT be consumed in the reaction. - A catalyst effectively provides a path with a LOWER activation energy for the reaction to proceed to completion. What effect did the physical state of reactants have on the reaction rate? What is the reason for the effect? correct answer: - The physical state of the reactions affects the rate of a reaction by changing the number of atoms or molecules on the surface where they an collide. - If the reaction occurs in the LIQUID STATE: the molecules are freer to move an more collisions will occur... VERSUS - If the reaction occurs in the SOLID STATE: the collisions are limited to the atoms on the surface. **Note: Smaller particles have more surface area per gram**