Unit 8 Electrochemistry Applications Lesson 4 Electrochemistry in

Unit 8: Electrochemistry Applications Lesson 4: Electrochemistry in Real Life

A. The Breathalyser • Alcohol consumed moves from the stomach into the blood stream, and some of it moves from the blood stream into the lungs. • The movement of alcohol between the blood and the alveoli in the lungs is an equilibrium process, so the ratio of alcohol in the breath to alcohol in the blood is a constant. • Exhaled air is mixed with a standardized solution containing K 2 Cr 2 O 7 and H 2 SO 4. . .

The Breathalyser, continued • If ethanol is present, it will be oxidized according to the reaction: C 2 H 5 OH + K 2 Cr 2 O 7 + H 2 SO 4 → CH 3 COOH + Cr 2(SO 4)3 + K 2 SO 4 + H 2 O • The reduced form of chromium is the Cr 3+ ion, which is dark green. • The greater the intensity of the green colour, the greater the breath alcohol content (BAC).

Brain Break! Double Shutter

B. Batteries and Fuel Cells Lead-Acid Storage Battery (pg. 230) Zinc-Carbon Battery (pg. 231) Alkaline Dry Cell (pg. 232) Fuel Cells (pg. 233) • Read your assigned section and write down the battery or cell’s: • Basic structure (including what is used as the anode, the cathode, and the electrolyte solution) • Advantages and/or disadvantages • Common uses • Form a group of four, and explain to each other what you’ve learned. Take notes on what the others share with you!

Homework: • Review your notes on the four different batteries/cells. There will be a quiz next class!