Problem 55 - Chemistry Matter and Change

Question

What is the difference between a solute and a solvent?

Step-by-Step Solution

Answer

The solute is dissolved, and the solvent dissolves it.

Step 1: Define Solute

A solute is a substance that is dissolved in a liquid to form a solution. It is usually present in a smaller amount compared to the solvent. For example, in a saltwater solution, the salt is the solute.

Step 2: Define Solvent

A solvent is a substance that dissolves a solute, resulting in a solution. It is usually present in a larger amount. In many solutions, like saltwater, water is the solvent.

Step 3: Compare Solute and Solvent

The solute is the substance that gets dissolved, while the solvent is the substance that does the dissolving. The key difference is the function and typical concentration within the solution.

Key Concepts

Solute

The term "solute" refers to the component in a solution that is present in a smaller amount and is dissolved by the solvent. When you dissolve sugar in water to make a sweet drink, the sugar is the solute. It becomes dispersed at a molecular level throughout the solvent.

Here are some key points about solutes:

• They can be solid, liquid, or gas.
• In a sugar-water solution, sugar is the solute.
• When a solute dissolves, it spreads uniformly throughout the solvent.

Understanding the role of the solute is crucial, as it determines the nature of the solution that is formed.

Solution

A solution is a homogeneous mixture composed of two or more substances. In everyday life, you encounter solutions all the time, such as tea, coffee, and soda.

Characteristics of a solution include:

• Homogeneity: Solutions are uniform in composition.
• They consist of a solute and a solvent.
• Solutions can be in different phases: liquid, gas, or solid.

This kind of consistency in composition ensures that every part of the solution behaves the same way, making them quite predictable and useful in various applications.

Dissolution Process

The dissolution process is the way in which a solute integrates into a solvent to create a solution. This process involves breaking the solute's molecular bonds and spreading its particles throughout the solvent.

Steps in the dissolution process include:

• Solvent molecules surround and interact with solute particles.
• Solute particles are separated and mixed evenly into the solvent.
• This mixing forms a stable, uniform solution.

Understanding this process helps in predicting how quickly or completely a solute will dissolve, which depends on factors such as temperature and the nature of the solvent and solute.

Concentration

Concentration refers to the amount of solute present in a given quantity of solution or solvent. It is a measure of how much solute is dissolved in the solvent, affecting the properties and behavior of the solution.

Forms of expressing concentration include:

• Mass percent - the mass of solute divided by the total mass of the solution.
• Molarity - moles of solute per liter of solution.
• Molality - moles of solute per kilogram of solvent.

Concentration determines the intensity of interactions between solute and solvent molecules, influencing reactions when solutions are used in chemical experiments.