Question 1

What does Henry's law state?

Accepted Answer

At constant temperature, the solubility of a gas in a liquid is directly proportional to the partial pressure of that gas above the liquid. If the pressure is increased, the dissolved amount increases in the same proportion for the same gas-liquid pair.

Question 2

Why is partial pressure used for a gas mixture?

Accepted Answer

In a mixture, each gas has its own partial pressure. The dissolving gas follows Henry's law through its own partial pressure, not through the total pressure of all gases combined. For CO2 in a CO2-N2 mixture, the relevant value is P_CO2.

Question 3

How does the piston help in this experiment?

Accepted Answer

The piston changes the space above the liquid and represents a change in the pressure of the gas. In the mixture stop, equal numbers of CO2 and N2 molecules are shown, so their partial pressures are equal and P_total is 2P_CO2.

Question 4

Does Henry's law apply to every kind of dissolution?

Accepted Answer

No. This lab focuses on the solubility of a gas in a liquid. The statement is not being used here to describe the dissolution of a solid or a liquid as if all dissolution followed the same law.

Henry's Law: Gas Diving Into a Liquid

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