Question

a. What is meant by the solubility of a substance? b. What condition(s) must be specified when expressing the solubility of a substance?

Short answer

a. Solubility is the maximum amount of solute that can dissolve in a solvent at a specific temperature. b. Temperature and amount of solvent must be specified.

Step-by-step solution

Title - Define Solubility

Solubility is the maximum amount of solute that can dissolve in a given amount of solvent at a specific temperature to form a saturated solution.

Title - Specify Conditions

When expressing the solubility of a substance, two main conditions must be specified: 1. Temperature: Solubility usually increases with temperature. 2. Amount of Solvent: The amount of solvent in which the solute is dissolved must be indicated, typically in grams of solute per 100 grams of solvent.

Key concepts

Solubility of a Substance

Solubility refers to the capacity of a substance, called the solute, to dissolve in a solvent. The result is a homogeneous mixture known as a solution.
The amount of solute that can dissolve in the solvent up to the point it can't dissolve anymore varies and is specific to the substance. This limit is called the maximum solubility.
For instance, when no more sugar can dissolve in water, that solution becomes saturated. Beyond this point, any additional sugar will just settle at the bottom.

Solute and Solvent

The solute is the substance that is being dissolved. Examples of solutes include:

• Sugar in tea or coffee.
• Salt in water.
• Carbon dioxide in carbonated drinks.

The solvent is the substance that does the dissolving. It's usually present in greater quantity than the solute. Some common solvents are:

• Water, often called the 'universal solvent' because it can dissolve so many substances.
• Alcohol, commonly used to dissolve substances to create tinctures and other solutions.
• Acetone, used in nail polish remover to dissolve nail polish.

Role of Temperature in Solubility

Temperature significantly impacts the solubility of most substances. For many solids dissolved in liquids, solubility increases with an increase in temperature. Consider these points:

• When preparing a hot cup of tea, sugar dissolves more readily in hot water than in cold.
• Raising the temperature allows for more interactions between solute and solvent particles, leading to increased dissolution.

However, gases behave differently:

• Cold sodas stay fizzy but become flat when warm because carbon dioxide, the dissolved gas, is less soluble at higher temperatures.
• Aquatic life thrives at optimal temperatures because too much dissolved oxygen can escape when water warms.