4D50.42 - Diffusion of Ammonia and Hydrogen Chloride (FOR USE IN LECTURE HALLS ONLY)
Demonstrate the inverse relationship between molecular velocity and molecular mass.
OverviewDemonstrate the inverse relationship between molecular velocity and molecular mass.
Pull out the glass tube, chemical vessels, and corks out. Put out the safety materials (goggles, gloves, neutralizing baking soda and dilute HCl) including signs. Put out chemicals, and cut a length of pH paper to line the glass tube.
Right before class, pour meager amounts of acid and base (~3cc each) in the vessels and place the corks w/ cotton on the hooks in the vessels. The corks should just fit.
Tape the pH strip so it's upright, this way the meeting gases will create an angled union point on the paper, depending on the respective weight of the gases. The heavier gas will travel farther on the bottom of the tube, while the light will travel farther on the top.
Draw students’ attention to the pH paper in the tube. Simultaneously place the corks in opposite ends of the tube. It will take ~7 minutes for the gases to meet as seen on the pH paper (vivid pink and green), ~10minutes for the cloud to form.
You are dealing with concentrated acid and base, if you spill please neutralize with a dilute acid or base. Wear safety protection.
When finished, leave the corks in the tube, the demolab will disassemble and clean the system.
The Hydrochloric acid will begin fuming on contact with air
DO NOT BREATHE THE FUMES
DO NOT GET THE FUMES IN YOUR EYES
WEAR EYE AND HAND PROTECTION.