Biological Systems MCAT Practice Exam

According to Henry's Law, what factors influence the amount of gas that can dissolve in a liquid?

1. Temperature and pressure alone

2. Solubility of gas and partial pressure of gas

3. Atmospheric pressure and gas density

4. Volume of liquid and concentration of solute

The correct answer is: Solubility of gas and partial pressure of gas

The correct choice focuses on the key principles outlined in Henry's Law, which states that the amount of a gas that dissolves in a liquid at a constant temperature is directly proportional to the partial pressure of that gas above the liquid. This means that both the solubility of the gas in the liquid and the partial pressure exerted by the gas are crucial factors. The solubility of a gas refers to its ability to dissolve in a particular solvent under given conditions, which varies based on the nature of the gas and the solvent. On the other hand, the partial pressure of the gas is a measure of its concentration in the gaseous phase, and an increase in this pressure will typically increase the amount of gas that can dissolve in the liquid. The interplay between these two factors explains why different gases have differing solubilities in the same liquid and why increasing the pressure of a gas over a liquid enhances its dissolution. Other choices mention factors that are not pertinent to Henry's Law. For instance, while temperature can affect gas solubility generally (with higher temperatures usually resulting in lower solubility for gases), it is not included in the direct statement of Henry's Law. Additionally, atmospheric pressure and gas density do not specifically address the solub