Question

What is the difference between a solute and a solvent?

Short answer

A solute is a substance that gets dissolved in a solvent, typically present in a smaller amount, and can be a solid, liquid, or gas. On the other hand, a solvent is a substance in which a solute is dissolved, generally present in larger quantities and can also be a solid, liquid, or gas. For example, in a saltwater solution, salt is the solute, and water is the solvent.

Step-by-step solution

Defining a Solute

A solute is a substance that is dissolved in a solvent to create a solution. It is typically present in a smaller amount compared to the solvent and can be a solid, liquid, or gas. Examples of solutes include salt and sugar.

Defining a Solvent

A solvent is a substance in which a solute is dissolved to form a solution. It is generally present in a larger quantity than the solute and can also be a solid, liquid, or gas. The most common solvent is water, as many substances dissolve in water, making it a universal solvent.

Differences Between a Solute and a Solvent

1. A solute is the substance that gets dissolved in a solution, while a solvent is the substance in which the solute gets dissolved. 2. The solute is usually present in smaller amounts, and the solvent is present in larger amounts within a solution. 3. The solute does not change its physical state after dissolving in the solvent, whereas the solvent changes its state to dissolve the solute.

Example: Saltwater

In a saltwater solution, salt is the solute because it is the substance being dissolved, and water is the solvent because it is the substance in which the salt is being dissolved. In this example, there is a smaller amount of salt compared to water, so it's clear that salt acts as the solute and water acts as the solvent.

Key concepts

Solution Chemistry

When we talk about solution chemistry, we're exploring the branch of chemistry that deals with the study of solutions; that is, homogeneous mixtures composed of two or more substances. In a solution, a solute is the substance that is dissolved, while the solvent is the substance that does the dissolving.

For a better understanding, imagine making lemonade. The sugar you stir into the water acts as the solute, and the water is the solvent. The resulting sweet liquid is a homogenous mixture or a solution. Solutions are crucial in various scientific processes and industrials applications because the properties of solutions, such as boiling point and freezing point, vary from those of the solute and the solvent.

Concentration and Saturation

The concentration of a solution tells us how much solute is present compared to the solvent. It can be expressed in various units, such as molarity or mass percent. The saturation point of a solution occurs when no more solute can dissolve; any additional amount will simply accumulate as excess.

Electrolytes and Nonelectrolytes

Additionally, in solution chemistry, solutes are classified as electrolytes or nonelectrolytes. Electrolytes are substances that, when dissolved in water, result in a solution that can conduct electricity. Non-electrolytes do not impart this conductive ability to the solution.

Dissolving Process

Understanding the dissolving process helps in grasping how a solution forms. This process involves the breaking and forming of bonds between molecules or ions of the solute and the molecules of the solvent.

Steps in the Dissolving Process

Initially, the solute particles detach from each other. Then, the solvent molecules cluster around the solute particles, which is referred to as solvation when the solvent is water. During solvation, the molecules of the solvent interact with and stabilize the solute particles, dispersing them into the solvent.

Factors Affecting Dissolving

Several factors can influence this process, such as temperature, agitation and surface area, and the nature of the solute and solvent. Increased temperature generally speeds up the dissolving process, agitation helps distribute the solute particles throughout the solvent, and a larger surface area (e.g., crushing a solid solute) allows the solvent to interact with more particles simultaneously.

Universal Solvent

Water is often referred to as the universal solvent because it dissolves more substances than any other liquid. This is primarily due to water's polar nature—its molecule has a positive charge on one side and a negative charge on the other side, allowing it to interact with various solutes.

Why is Water Considered Universal?

Because of its polarity, water can dissolve ionic compounds, like salt, by surrounding and separating their positively (cations) and negatively charged (anions) particles. Water can also dissolve many covalent bond substances by forming hydrogen bonds with them.

Importance in Biological Systems

The property of being a universal solvent makes water essential in biological systems, where it transports nutrients and waste products, participates in chemical reactions, and helps regulate body temperature. However, despite its reputation, water can't dissolve everything. Substances like oils and other non-polar compounds do not mix well with water because they lack the charge features necessary to interact effectively with water molecules.