Lesson 1: Two Kinds of Mixtures

A glass of orange juice is a mixture. A glass of water that has some salt dissolved in it is also a mixture. These two mixtures do not look the same. The glass of salt water is clear and colourless and looks just like a glass of water. The glass of orange juice is a bright orange colour, and you cannot see through it like you can see through a glass of water.

Read the introduction to two kinds of mixtures up to Mechanical Mixtures on page 42.

Question 1. From the flowchart in Figure 3.1, what are the two categories of mixtures?

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You likely know what a mechanical mixture is just by looking at the term. Just to be sure, read the section Mechanical Mixtures on page 42.

Question 2. What is the definition of mechanical mixture?

Question 3. What are the particles visible in the orange juice in Figure 3.2?

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You are likely familiar with solutions such as pop, tea, and coffee. If you add a teaspoon of sugar to a glass of water and stir it, the white sugar granules seem to disappear. You are left with what appears to be a glass of ordinary water. The sugar is said to dissolve in the water. Read the section Solutions and Parts of Solutions on page 43.

Question 4. What is meant by dissolve?

Question 5. What is the definition of a solution?

Question 5. What are the two parts of a solution?

Question 6. Define solute.

Question 7. Define solvent.

Question 8. Explain the two things you can do to tell if a mixture is a mechanical mixture or a solution.

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Solutions are often thought of as mixtures in a liquid state, such as sugar dissolved in water. Solutions do not have to be liquid. The air that you breathe is a solution: nitrogen is the solvent and other gases such as oxygen and carbon dioxide are the solutes. Metal alloys such as stainless steel and gold used in jewelry are solid solutions.

Answer questions 1 and 3 of Check Your Understanding on page 44 of your textbook.

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Answers to Questions:

Question 1. From the flowchart in Figure 3.1, what are the two categories of mixtures?

The two categories of mixtures are mechanical mixtures and solutions.

 

Click to return to where you left off in this lesson.

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 2.What is the definition of mechanical mixture?

A mechanical mixture is a mixture in which more than one type of particle is visible. If you can see particles in the mixture, it is a mechanical mixture.

Question 3. What are the particles visible in the orange juice in Figure 3.2?

The visible particles on the orange juice are pieces of orange pulp. A glass of orange juice made from crystal powder may not have visible particles.

 

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Answers to Questions:

Question 4. What is meant by dissolve?

Dissolve means to break up into the component parts and to pass into solution. For example, when sugar dissolves in a glass of water, the sugar crystals break down into sugar molecules that are then distributed throughout the glass of water.

Question 5. What is the definition of a solution?

A solution is a uniform mixture of two or more substances. You cannot see or filter out the substances in a solution.

Question 6. Define solute.

The solute is the substance that dissolves. There is less solute than solvent in a solution.

Question 7. Define solvent.

The solvent is the substance that dissolves the solute. There is more solvent than solute in a solution.

Question 8. Explain the two things you can do to tell if a mixture is a mechanical mixture or a solution.

You can look at the mixture. If you can see different types of particles, then it is a mixture and not a solution. A glass of muddy water where you can see particles suspended in the liquid is a mechanical mixture.

You can filter the mixture. If any particles are trapped in the filter, it is a mechanical mixture and not a solution.

 

Click to return to where you left off in this lesson.

 

 

 

 

 

 

 

 

 

 

 

Check Your Understanding:

1 a. mechanical mixture
1 b. solution
1 c. solution
1 d. solution
1 e. mechanical mixture

3 a. Water is the solvent, salt is the solute.
3 b. Water is the solvent, baking soda is the solute.
3 c. Nitrogen is the solvent, oxygen and other gases are the solutes.
3 d. Gold is the solvent, silver is the solute.


Now, do Assignment 3A. Please page forward to the computer-scored assignment.