A student-prepared silver−silver chloride reference electrode is described. The chemical deposition of AgCl(s) onto Ag(s) is accomplished in 30−50 s by placement of a Ag(s) wire in laundry bleach. An autopipettor tip with an agarose gel plug serves as the electrode housing; the agarose gel contains predissolved KNO 3 . Reference electrode preparation is completed in about 10 min, allowing enough time for laboratory exercises that utilize the electrode. Preparation and operation of the electrode and recovery of the Ag(s) are designed to teach a number of important chemistry principles.

The acid ionization constant, K a , of acetic acid and the base ionization constant, K b , of ammonia are determined easily and rapidly using a datalogger, a pH sensor, and a conductivity sensor. To decrease sample preparation time and to minimize waste, sequential aliquots of a concentrated standard are added to a known volume of water and measurements are made after each addition. In this laboratory exercise, students show that K a and K b are constants, compare and contrast pH and conductivity approaches, and evaluate how solution components (weak acid alone and weak acid plus conjugate base) affect the results.

In this general chemistry laboratory exercise, the absorbance of [CoCl(iPrOH)3]+, where iPrOH is isopropyl alcohol, is used to determine the equilibrium constants for its reaction with methanol to form [CoCl(iPrOH)2(MeOH)3]+ in the temperature range ∼10 to 20 °C. The absorbance versus concentration calibration plot is determined by sequential additions of a concentrated [CoCl(iPrOH)3]Cl standard to iPrOH. The equilibrium mixture is cooled in a CaCl2–ice bath, and measurements of temperature and absorbance are made at various time intervals as the solution warms to room temperature. The variation in the equilibrium constant as a function of temperature is used to determine the Gibbs energy, enthalpy, and entropy.

In most general chemistry laboratories, the heat capacity of a calorimeter is determined by measuring the temperature changes that occur when a known mass of water at a higher temperature is added to a known mass of water (or solution) in the calorimeter at room temperature. Another approach is to add a known quantity of electrical energy and measure the temperature change.

In this laboratory experiment, students apply a mass-based approach to determine the Henry’s law constant for CO2 using a small bottle of a diet carbonated beverage. The calculations are challenging; therefore, team-based learning is encouraged. Our students reported values of 0.033 ± 0.003 mol/(L·atm) at room temperature (18–21 °C); when surveyed, these students indicated a high degree of enthusiasm and engagement and development of teamwork abilities.