Featured in PASCO’s College Chemistry Instructor Guide

College Chemistry Instructor Guide

(PS-3803A)

College Instructor edition with 36 experiments covering introductory and general chemistry topics.

Breathalyzer Test

Lab Summary

Use a colorimeter to determine the concentration of an ethanol solution using the Breathalyzer™ test: chemical oxidation of ethanol by acidic dichromate.

Theory

Students understand the chemical oxidation of ethanol by acidic dichromate, as used in Breathalyzer tests for alcohol, and determine the concentration of an ethanol solution.

Method

Students gain experience conducting the following procedures:

  • Carrying out a reaction between ethanol and potassium chromate that uses a catalyst and hot water bath to increase the rate of reaction.
  • Developing a calibration curve using spectroscopic measurements to use for calculating the concentration of an ethanol solution.
  • Advanced preparation of solutions.

Sensors / Equipment Used:

PASPORT Colorimeter Sensor

(PS-2121)

Our PASPORT Colorimeter records all 4 wavelengths simultaneously--no need to guess at wavelength to get a quality measurement.

Materials Used:

Erlenmeyer flask, 125-mL - 7
Volumetric flask, 100-mL 
Graduated pipet, 10-mL 1
Graduated pipet, 5-mL 
Pipet, plastic, 1-mL 
Graduated cylinder, 100-mL 
Beaker, 25-mL - 2
Beaker, 100-mL 
Beaker, 400-mL - 2
Beaker, 250-mL 
Beaker, 1-L 
Ring stand 
Clamps, utility - 2
Hot plate 
15% Sulfuric acid (H2SO4)  -800 mL
Silver nitrate (AgNO3), 15% - 10 mL
5.10 × 10-2 M Potassium dichromate (K2Cr2O7) - 30 mL
Ethanol solution, unknown concentration - 5 mL
Marking pen 
Wash bottle with distilled water 

The Associated Bundle:

Advanced Chemistry Standard Sensor Bundle

(PS-2928A)

Contains the probeware for completing experiments in the College Chemistry lab manual.

Interface Required

This experiment may require software and an interface for data collection.