Sistem Koloid (1) | Jenis-jenis Koloid | Kimia kelas 11

Summary

In this educational video, the presenter explains the concept of colloidal systems, focusing on their definition and various types. The video distinguishes between solutions, colloids, and suspensions, highlighting their differences in particle size, clarity, phase composition, and stability. It further categorizes colloids based on the dispersion phase and medium, offering examples like smoke, paint, and foam. The goal is to help students understand the characteristics of colloidal systems and their practical examples in everyday life, making the topic accessible and engaging for viewers.

Takeaways

• 😀 The colloidal system is a type of dispersion system where one substance is evenly spread within another substance. The dispersed substance is called the dispersed phase, and the medium is called the dispersing medium.
• 😀 Dispersed systems can be categorized into three types based on the particle size: solutions (very fine particles), colloids (intermediate-sized particles), and suspensions (larger particles).
• 😀 The key differences between solutions, colloids, and suspensions lie in particle size, homogeneity, filtration ability, and stability. Solutions are homogeneous, colloids are heterogeneous but appear homogeneous, and suspensions are clearly heterogeneous.
• 😀 Solutions have very fine particles (less than 10^-9 m) and are stable, meaning the dispersed substance does not separate. Colloids have particles between 10^-9 m and 10^-7 m and are relatively stable, while suspensions have particles larger than 10^-7 m and tend to separate or settle over time.
• 😀 Colloids can be classified based on the phases of the dispersed and dispersing substances. There are eight main types of colloids based on this classification.
• 😀 A sol is a colloid where the dispersed phase is solid and the dispersing medium is liquid. If both phases are solid, it’s called a solid sol.
• 😀 An emulsion is a colloid where the dispersed phase is liquid and the dispersing medium is also liquid. If the dispersing medium is solid, it's called a solid emulsion.
• 😀 Aerosols are colloids where the dispersed phase is gas. If the dispersing medium is liquid, it’s an aerosol of liquid in gas, and if the medium is solid, it’s an aerosol of solid in gas.
• 😀 Examples of colloidal systems include smoke (solid in gas), paint (solid in liquid), fog (liquid in gas), and foam (gas in liquid).
• 😀 To identify the type of colloid, focus on the phase of the medium, as it usually matches the visible phase of the colloid. For example, smoke is classified as aerosol solid because it appears gaseous but is a solid dispersed in gas.

Q & A

What is a colloidal system?

A colloidal system is a type of dispersion system where one substance is spread evenly throughout another, with the dispersed substance known as the dispersed phase and the substance it is spread within called the dispersion medium.

How are dispersion systems classified based on particle size?

Dispersion systems are classified into three categories based on particle size: fine dispersion (solution), colloidal dispersion, and coarse dispersion (suspension).

What are the key differences between solutions, colloids, and suspensions?

Solutions have particles smaller than 1 nanometer, are homogeneous, and cannot be filtered. Colloids have particles between 1 and 100 nanometers, appear homogeneous macroscopically but are heterogeneous, and can be filtered using ultra-filters. Suspensions have particles larger than 100 nanometers, are heterogeneous, and can be filtered easily.

Why is a colloidal system considered a heterogeneous mixture?

Although a colloid appears homogeneous to the naked eye, it consists of two phases, making it a heterogeneous mixture. The dispersed particles are distinct from the dispersion medium at a microscopic level.

What is the size range of particles in a colloid?

The particle size in a colloidal system ranges from 1 nanometer (10^-9 meters) to 100 nanometers (10^-7 meters).

How does the stability of solutions, colloids, and suspensions differ?

Solutions are stable, meaning the dispersed substance will not separate. Colloids are relatively stable but may separate over time. Suspensions are unstable and the dispersed particles will eventually settle or separate.

What are the different types of colloids based on the phases of the dispersed substance and the dispersion medium?

Colloids can be classified based on whether the dispersed phase is solid, liquid, or gas and whether the dispersion medium is solid, liquid, or gas. For example, 'sol' is a solid dispersed in a liquid, while 'aerosol' refers to a solid or liquid dispersed in a gas.

What is the definition of an emulsion in colloidal systems?

An emulsion is a type of colloid where the dispersed phase is a liquid and the dispersion medium is also a liquid. Examples include milk and mayonnaise.

How can you distinguish between different types of colloids, such as sols and emulsions?

The main factor in distinguishing between different types of colloids is the phase of the dispersed substance. For instance, if a solid is dispersed in a liquid, it's called a sol, while a liquid dispersed in another liquid is called an emulsion.

Can colloidal particles be filtered with ordinary filters?

No, colloidal particles cannot be filtered using regular filters. They require ultra-filters due to their small size.