, ZOL2601 Assignment 2 Semester 1 2026 - DUE 23 March 2026
Question 1
The amount of gas that dissolves in water is affected by several environmental
and chemical factors. The four main factors that influence gas solubility in water
are temperature, pressure, salinity, and the nature of the gas.
1. Temperature
Temperature has an inverse relationship with the solubility of gases in water. As
the temperature of water increases, the solubility of gases decreases. This occurs
because higher temperatures increase the kinetic energy of gas molecules,
allowing them to escape more easily from the water into the atmosphere.
Conversely, colder water can hold more dissolved gas, such as oxygen.
2. Pressure
Pressure has a direct relationship with the solubility of gases in water. When the
pressure above the water increases, more gas molecules are forced into the
water, which increases the amount of gas that dissolves. This principle is
described by Henry’s Law, which states that the amount of gas dissolved in a
liquid is proportional to the pressure of that gas above the liquid.
3. Salinity
Salinity refers to the amount of dissolved salts in water. As salinity increases, the
solubility of gases in water decreases. This is known as the “salting-out effect.”
The dissolved salt ions compete with gas molecules for space among water
molecules, leaving less space for gases to dissolve.
4. Nature of the Gas
Different gases dissolve in water at different levels depending on their chemical
properties. Gases that react with water or are more chemically soluble tend to
dissolve more easily. For example, gases like carbon dioxide dissolve more
readily in water compared to gases such as oxygen or nitrogen because they can
interact chemically with water molecules.
Question 1
The amount of gas that dissolves in water is affected by several environmental
and chemical factors. The four main factors that influence gas solubility in water
are temperature, pressure, salinity, and the nature of the gas.
1. Temperature
Temperature has an inverse relationship with the solubility of gases in water. As
the temperature of water increases, the solubility of gases decreases. This occurs
because higher temperatures increase the kinetic energy of gas molecules,
allowing them to escape more easily from the water into the atmosphere.
Conversely, colder water can hold more dissolved gas, such as oxygen.
2. Pressure
Pressure has a direct relationship with the solubility of gases in water. When the
pressure above the water increases, more gas molecules are forced into the
water, which increases the amount of gas that dissolves. This principle is
described by Henry’s Law, which states that the amount of gas dissolved in a
liquid is proportional to the pressure of that gas above the liquid.
3. Salinity
Salinity refers to the amount of dissolved salts in water. As salinity increases, the
solubility of gases in water decreases. This is known as the “salting-out effect.”
The dissolved salt ions compete with gas molecules for space among water
molecules, leaving less space for gases to dissolve.
4. Nature of the Gas
Different gases dissolve in water at different levels depending on their chemical
properties. Gases that react with water or are more chemically soluble tend to
dissolve more easily. For example, gases like carbon dioxide dissolve more
readily in water compared to gases such as oxygen or nitrogen because they can
interact chemically with water molecules.
