, ZOL2601 Assignment 2 (COMPLETE ANSWERS)
Semester 1 2026 - DUE 23 March 2026; 100% Correct
solutions and explanations.
Question 1
The amount of gas that can dissolve in water is influenced by several important factors.
These factors determine whether more gas will dissolve in the water or whether the gas
will escape from the water. The four main factors are temperature, pressure, the nature of
the gas, and the nature of the solvent.
Temperature
Temperature has a significant effect on the solubility of gases in water. As the
temperature of water increases, the solubility of gases generally decreases. This means
that warmer water holds less dissolved gas than colder water. When water is heated, the
gas molecules gain energy and move more rapidly, making it easier for them to escape
from the liquid into the atmosphere. This is why cold water can contain more dissolved
oxygen than warm water, which is important for aquatic organisms that rely on oxygen in
water.
Pressure
Pressure also influences how much gas can dissolve in water. When the pressure of a gas
above the water increases, more gas dissolves in the water. This relationship is explained
by Henry’s Law, which states that the solubility of a gas in a liquid is directly
proportional to the pressure of that gas above the liquid. Under high pressure, gas
molecules are forced into the liquid more easily, increasing the amount of dissolved gas.
Conversely, when the pressure decreases, the dissolved gas tends to escape from the
water.
Nature of the Gas
The chemical properties of the gas itself also affect how well it dissolves in water. Some
gases dissolve more easily than others depending on their molecular structure and
polarity. Gases that can interact strongly with water molecules, such as carbon dioxide or
ammonia, tend to dissolve more readily. In contrast, gases that are non-polar or have
weak interactions with water molecules, such as nitrogen or oxygen, are generally less
soluble.
Nature of the Solvent
Semester 1 2026 - DUE 23 March 2026; 100% Correct
solutions and explanations.
Question 1
The amount of gas that can dissolve in water is influenced by several important factors.
These factors determine whether more gas will dissolve in the water or whether the gas
will escape from the water. The four main factors are temperature, pressure, the nature of
the gas, and the nature of the solvent.
Temperature
Temperature has a significant effect on the solubility of gases in water. As the
temperature of water increases, the solubility of gases generally decreases. This means
that warmer water holds less dissolved gas than colder water. When water is heated, the
gas molecules gain energy and move more rapidly, making it easier for them to escape
from the liquid into the atmosphere. This is why cold water can contain more dissolved
oxygen than warm water, which is important for aquatic organisms that rely on oxygen in
water.
Pressure
Pressure also influences how much gas can dissolve in water. When the pressure of a gas
above the water increases, more gas dissolves in the water. This relationship is explained
by Henry’s Law, which states that the solubility of a gas in a liquid is directly
proportional to the pressure of that gas above the liquid. Under high pressure, gas
molecules are forced into the liquid more easily, increasing the amount of dissolved gas.
Conversely, when the pressure decreases, the dissolved gas tends to escape from the
water.
Nature of the Gas
The chemical properties of the gas itself also affect how well it dissolves in water. Some
gases dissolve more easily than others depending on their molecular structure and
polarity. Gases that can interact strongly with water molecules, such as carbon dioxide or
ammonia, tend to dissolve more readily. In contrast, gases that are non-polar or have
weak interactions with water molecules, such as nitrogen or oxygen, are generally less
soluble.
Nature of the Solvent
