1.2.4 - Tipos de misturas

Summary

This lecture explores the concept of mixtures, focusing on the distinction between homogeneous and heterogeneous mixtures. It explains that a homogeneous mixture, or solution, has a single phase, while a heterogeneous mixture contains more than one phase. The discussion covers saturation levels in solutions, the role of solutes and solvents, and how the solubility limit determines the saturation point. The lecture also touches on the identification of solutes and solvents, emphasizing their quantities and the final physical state of the mixture. Further details on phases of matter will be explored in future lessons.

Takeaways

• 😀 A substance is considered pure when it contains only one type of molecule, but this is not practically possible (e.g., 100% pure water).
• 😀 When combining multiple substances, a mixture is formed. A mixture can be either homogeneous or heterogeneous based on its phases.
• 😀 A homogeneous mixture has only one phase, while a heterogeneous mixture has multiple phases.
• 😀 Homogeneous mixtures are also known as solutions, which always have a single phase.
• 😀 Solutions can be either saturated (at the maximum solubility of a substance) or unsaturated (can still dissolve more of the substance).
• 😀 Saturated solutions are at the limit of solubility, meaning no more solute can dissolve in the solvent.
• 😀 Unsaturated solutions have not yet reached the solubility limit and can dissolve more solute.
• 😀 The solute is the substance in lesser quantity, and the solvent is the substance in greater quantity in a solution.
• 😀 In a typical saltwater solution, water is the solvent, and salt is the solute. However, the roles of solute and solvent can depend on the situation.
• 😀 The final physical state of the solution determines which substance is considered the solvent, even if the solute is present in a larger amount.
• 😀 The solubility limit and the concept of solutions will be explored further in the next lesson, which will cover phases of matter.

Q & A

What is the difference between a pure substance and a mixture?

A pure substance consists of only one type of molecule, while a mixture contains two or more different substances. For example, pure water contains only water molecules, but a mixture like salt water contains both water and salt molecules.

What are the two types of mixtures discussed in the script?

The two types of mixtures are homogeneous and heterogeneous mixtures. Homogeneous mixtures have only one phase, while heterogeneous mixtures have more than one phase.

What is a homogeneous mixture, and what is another name for it?

A homogeneous mixture is a mixture that has a single phase, meaning its components are uniformly distributed. It is also referred to as a solution.

How do you define a solution as saturated?

A solution is considered saturated when it contains the maximum amount of solute that can dissolve at a given temperature. If more solute is added, it will not dissolve and may precipitate out of the solution.

What is the difference between a saturated and an unsaturated solution?

A saturated solution is at its maximum capacity for dissolving solute, meaning no more solute can dissolve at the given temperature. An unsaturated solution, on the other hand, has not reached its solubility limit and can still dissolve more solute.

What defines the solvent in a solution?

The solvent is the component of a solution that is present in the greater quantity. It is typically the substance in which the solute dissolves, such as water in saltwater.

How does the state of matter of the solvent help define it in some solutions?

In some solutions, the solvent is determined not only by its quantity but also by the final state of the mixture. For example, if the final mixture is liquid, then the substance that was originally liquid is often considered the solvent, even if the solute was in larger quantity.

What happens when a solution becomes supersaturated, and why is it unstable?

A supersaturated solution occurs when more solute is dissolved than is normally possible at a given temperature, creating an unstable state. Any disturbance or change can cause the excess solute to precipitate, making the solution unstable.

What is the role of temperature in the solubility of a substance?

Temperature plays a key role in solubility because the solubility of most solids in liquids increases with temperature. For example, as the temperature of water rises, it can dissolve more salt, which increases the solubility of the salt.

How does the example of salt in water illustrate the concepts of solute, solvent, and saturation?

In the example, water acts as the solvent, and salt is the solute. As salt is added to the water, it dissolves until the solution becomes saturated. At that point, no more salt can dissolve in the water, demonstrating the concept of a saturated solution.