Chemistry Is A Gas

Blake, Thelma B. Louis Worth Experimental School

Objectives: The student will be able to apply the conventional gas laws in the determination of volume changes resulting from changes in temperature, pressures, or number of moles of the gas. Apparatus Needed: Hypodermic Spring Scale, weights or books, hot plates, gas can, glass tubing, rubber stopper, 500 ml beakers, 125 ml flasks, tongs, clamps, gloves, and balloons. Recommended Strategy: The following strategies demonstrate the use of Boyle's Law which is P1V1=P2V2.

1. Hypodermic Syringe Scale (Elasticity of a Gas Apparatus): Use
weights or books on top of the syringe scale to measure pressure
with this additional weight.
2. Can Carbonated Water: You've seen Boyle's Law in action when you've
shaken a can of pop. As you open it the liquid ends on you and your
3. Atmospheric Pressure: Use a gas can and boil a few ounces of water
in it, remove from heat and close the can. Let the can cool. The
steam in can cools, condenses, reducing the vapor pressure inside
the can; the normal external atmospheric pressure is greater than
the internal pressure and the can collapses. Air pressure is a force
that acts on the outside surface.

The following strategies demonstrate the use of Charles' Law
V1T2=V2T1. 1. Temperature-Volume Demonstration: The temperature-volume
relationship of a gas can be seen by inverting a round-bottom thick
wall flask having a piece of glass tubing inserted in a rubber
stopper in its neck into a beaker of cold water. First boil a small
amount of water in the flask and immerse the flask into the beaker
of cold water. The water level in the flask increases. When an
additional amount of hot water is poured over the flask, it will
cause the water level inside to decrease.
2. Demonstrations with Balloon: Cover the mouth of a small flask with
a rubber balloon and gently heat the flask. The balloon will
inflate. Use another small flask and let a small amount of water
boil in it. Remove from heat and place a balloon over the mouth of
the flask. The balloon is drawn into the flask.
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