Question

What theory could be used to determine the amount of oxygen that is dissolved in water at sea level? A. Henry's law B. Boyle's law C. Raoult's law D. Le Châtelier's principle

Short answer

A. Henry's law

Step-by-step solution

- Understand the Problem

The task is to determine which theory or law applies to calculating the amount of oxygen dissolved in water at sea level.

- Identify Possible Theories

Examine the given options: Henry's law, Boyle's law, Raoult's law, and Le Châtelier's principle.

- Review Henry's Law

Henry's law states that the amount of gas that dissolves in a liquid is directly proportional to the partial pressure of that gas above the liquid, holding temperature constant.

- Review Boyle's Law

Boyle's law relates the pressure and volume of a gas, stating that the pressure of a given mass of gas is inversely proportional to its volume, at constant temperature.

- Review Raoult's Law

Raoult's law deals with the vapor pressure of ideal mixtures and the lowering effect caused by the addition of a non-volatile solute.

- Review Le Châtelier's Principle

Le Châtelier's principle predicts how a chemical system at equilibrium will respond to a change in concentration, temperature, and pressure.

- Select the Appropriate Theory

Based on the definitions, Henry's law is specifically about the solubility of gases in liquids under pressure, which fits the requirement of determining dissolved oxygen in water at sea level.

Key concepts

Gas Solubility

Gas solubility refers to the ability of a gas to dissolve in a liquid. Imagine mixing sugar in water.
The sugar dissolves quite easily.
Gases work similarly, even though they are much harder to see. The amount of gas that can dissolve in a solution depends on several factors: pressure, temperature, and the nature of the gas and liquid.
According to **Henry's Law**, one of the crucial factors affecting gas solubility is **partial pressure**.
The higher the pressure of the gas above the liquid, the more gas will dissolve.
This principle is why carbonated drinks fizz when you open them.
When the pressure is released, the dissolved gas escapes.

Partial Pressure

Partial pressure is the pressure that one gas in a mixture would exert if it occupied the entire volume on its own.
When looking at a liquid-gas scenario, like oxygen in water, the partial pressure of oxygen determines how much oxygen will dissolve in the water.
If you imagine a sealed bottle of water and oxygen, the oxygen inside the bottle creates its own pressure.
This pressure pushes oxygen molecules into the water.
According to Henry's Law, the concentration (C) of dissolved gas is proportional to its partial pressure (P):
\[ C = kP \]Here, **k** is **Henry's Law constant**, which varies for different gases and temperatures.
Increasing the partial pressure increases the dissolved gas concentration proportionally.
This relationship is critical for calculating dissolved oxygen levels in scenarios like ocean water at sea level.

Ocean Dissolved Oxygen

Dissolved oxygen in oceans is essential for marine life.
Fish and other aquatic creatures rely on it for survival.
The amount of dissolved oxygen can fluctuate due to various factors like temperature and the partial pressure of oxygen in the atmosphere.
At sea level, the atmosphere exerts a certain pressure on the ocean's surface.
According to Henry's Law, this atmospheric pressure determines how much oxygen gets dissolved.
Warmer water holds less oxygen because gas molecules have more energy to escape into the atmosphere.
On the flip side, colder water can hold more oxygen.
Understanding these principles helps explain why you might see more marine life in cooler waters with higher dissolved oxygen levels.
So keep Henry's Law in mind when studying different ecosystems and how they support life.