Physical Science Institute
Summer 2013
States of Matter
Predict, Observe, Explain-Part 1
PREDICT
When ammonia gas (NH3) reacts with hydrogen chloride gas (HCl) they react chemically and produce a white solid
(NH4Cl).
The diagram below shows a glass tube in which ammonia (NH3) gas is introduced in the left side of the tube and
hydrogen chloride (HCl) gas is introduced in the right side of the tube. Both gases are at room temperature. The glass
tube is then sealed at both ends.
Predict where the two gases—NH3 and HCl—will meet by drawing a vertical line where you think the white solid (NH4Cl)
will form.
OBSERVE
Watch the following YouTube video of this demonstration: Pontociência - Cinética dos gases
http://www.youtube.com/watch?v=Lzt9v-eo_zY
Draw a vertical line in the diagram below to show approximately where the gases meet as shown in the previous video.
EXPLAIN
Explain the results of this demonstration using the Kinetic Molecular Theory.
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