3.3.4 CIA Demonstration: Self-Inflating Hydrogen Balloons

Question 1

CIA Demonstration: Self-Inflating Hydrogen Balloons

Answer 1

• The chemical reaction of magnesium and hydrochloric acid produces hydrogen gas, which can be collected in balloons.
• The sizes of the four balloons reflect the stoichiometry of this reaction.

Question 2

note

Answer 2

• The chemical reaction of magnesium (Mg) and hydrochloric acid (HCl) produces hydrogen gas (H2), which can be collected in balloons.
• Each flask contains one-tenth molehydrochloric acid. This amount of hydrochloric acid reacts with one-twentieth mole magnesium metal to produce one-twentieth mole hydrogen gas. If less magnesium is present, less hydrogen gas will be produced.
• The sizes of the four balloons reflect the stoichiometry of this reaction.
• In the first two reactions, magnesium is the limiting reagent. Less than one-twentieth mole hydrogen gas is produced in each of these reactions. This is reflected in the sizes of the attached balloons relative to the third balloon.
• The third reaction contains the exact stoichiometric ratio of magnesium to hydrochloric acid. The magnesium and the hydrochloric acid react completely, producing one-twentieth mole hydrogen gas.
• In the fourth reaction, hydrochloric acid is the limiting reagent. After all of the hydrochloric acid is consumed, one-twentieth mole hydrogen gas is produced, and one-twentieth mole magnesium metal remains. Since the same amount of hydrogen gas is produced in this reaction and in the third, the balloons inflate to roughly the same size.