Chemical Reactions Laboratory 2
- University of Waterloo credit: 0.25
- European Credit Transfer and Accumulation System (ECTS) credit: 3.0
- Prerequisite: CHEM 121L
- Corequisite: CHEM 125
- Textbook: CHEM 125L laboratory manual.
The CHEM 125L laboratory course is related to the lecture course, CHEM 125, but is a separate course and is graded independently. Experiments are designed to give students hands on experience which will support and enhance the concepts presented in CHEM 125, as well as the opportunity to strengthen laboratory skills and improve analysis techniques.
The following laboratory experiments are scheduled for the term:
1. Spectrophotometric Analysis: The chemistry of the Breathalyzer® reaction
This experiment determines the ethanol content of an unknown liquid sample utilizing a redox reaction between ethanol and potassium dichromate. A series of ethanol standard solutions are prepared and used to create a standard absorbance curve using a spectrophotometer. Using this standard curve, the concentration of the unknown is calculated.
2. Introduction to Calorimetry
This experiment introduces the use of calorimetry, measuring energy changes in reactions, as an analysis tool. A variety of reactions are performed and temperature changes are recorded to determine how the release or absorption of heat can be used to determine heat capacity, specific heat, molar enthalpy or reactant concentrations.
3. Factors affecting Reaction Rates: The iodide-persulphate reaction
A clock reaction is used to monitor and calculate the rate and rate constant of the iodide-persulphate reaction. With the experimental data obtained the effect of reactant concentrations, temperature, ionic strength and use of catalysts on the rate of reaction and the rate constant are observed.
4. pH Chemistry: Acid-base titrations and buffer solutions
This experiment introduces the fundamental concept of pH chemistry. The titration of a weak acid with a strong base and a weak base with a strong acid is monitored using a pH meter. Buffer solutions are prepared and subjected to different environments to observe the buffering capacity of various solutions. Measured pH values are compared to calculated theoretical values.
5. Titration analysis: Assessing the effectiveness of Antacids
This experiment introduces the technique of back-titration in which a known excess of acidic titrant is added to a commercial antacid sample and the excess acid is back-titrated with standardized NaOH, in order to determine which antacid neutralizes the most stomach acid. Students will need to overcome a variety of sample preparation and analysis issues that are common when working with over the counter products.
Please remember that the Undergraduate Calendar is always the official source for all course descriptions.