Balloon Racing (Comparing the Strengths of Different Acids)
- Page ID
- 127574
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Required Training |
Required PPE |
---|---|
UC Lab Safety Fundamentals |
Lab coat, safety glasses/goggles, nitrile gloves |
Equipment |
Chemicals |
Two balloons |
Two 0.5 gram portions of magnesium metal turnings |
2 Large test tubes |
20 mL 3N HCl |
2 short pieces of wire |
20 mL 3N Acetic acid |
Procedure:
1) Fill two balloons with magnesium turnings.
2) Fill one test tube with 20 mL 3N acetic acid and a second test tube with 20 mL 3N hydrochloric.
3) Mount the balloons to their respective test tubes and wrap the wire around the lip to make sure it does not fly off.
4) Lift the balloon to drop all of the magnesium turnings into the acid in both test tubes at the same time.
5) Note the rate at which both reactions progress and once completed, the final volumes on the balloons.
Discussion:
HCl (aq) + H2O → H3O+(aq) + Cl-(aq) Ka>>1
HOAc(aq) + H2O → H3O+(aq) + OAc-(aq) Ka = 1.8*10-5
Mg(s) + 2 H3O+(aq) → Mg2+(aq) + H2(g) + 2 H2O
The rate at which the acetic acid balloon will progress is slower than the rate of the hydrochloric acid balloon; however, since the acids are of equivalent molarity, the final volume of the balloons (the moles of hydrogen gas produced) will be the same.
Hazards:
Should the balloon fail, a vigorous reaction would proceed, open to the environment. For this reason, carefully ensure the wire will hold the balloon to the test tube, and wear PPE including a lab coat, goggles and gloves.
SOP:
Corrosive – Acetic Acid, Hydrochloric Acid
Disposal (by Storeroom):
Return acids to the storeroom. More acid than magnesium should be left unreacted, so neutralize the acids with an appropriate media such as sodium bicarbonate, and flush down the drain with copious amounts of water.