1. What Is a Solution? - Understanding Solutions
A solution has the same properties throughout. It contains solute particles (molecules or ions) that are too small to see.

2. What Is a Solution? - Understanding Solutions
Solutions can be made from any combinations of solids, liquids, and gases.

3. Colloids and Suspensions
- Understanding Solutions
Colloids and Suspensions
Colloids and suspensions are mixtures that have properties different from those of solutions.

4. Particles in a Solution
- Understanding Solutions
Particles in a Solution
When a solution forms, particles of the solute leave each other and become surrounded by particles of the solvent.

5. Effects of Solutes on Solvents
- Understanding Solutions
Effects of Solutes on Solvents
At 0ºC, pure water freezes, but water mixed with a solute does not. Solutes lower the freezing point of a solvent.
Liquid water solution
Solid (frozen) water

6. Identifying Main Ideas
- Understanding Solutions
Identifying Main Ideas
As you read the section “What is a Solution?”, write the main idea in a graphic. Then write three supporting details.
Main Idea
A solution is a well mixed mixture that contains a solvent and at least one solute.
Detail
Detail
Detail
Detail
The solvent is the substance present in the largest amount.
A solute is a substance present in a smaller amount than the solvent.
A solution has the same properties throughout.
A solution contains particles that are too small to see.

7. Click the Video button to watch a movie about universal solvent.
- Understanding Solutions
Universal Solvent
Click the Video button to watch a movie about universal solvent.

8. Calculating a Concentration
- Concentration and Solubility
Calculating a Concentration
To calculate the concentration of a solution, compare the amount of solute to the amount of solution and multiply by 100 percent.
For example, if a solution contains 10 grams of solute dissolved in 100 grams of solution, then its concentration can be reported as 10 percent.

9. Calculating a Concentration
- Concentration and Solubility
Calculating a Concentration
Practice Problem
A solution contains 12 grams of solute dissolved in 36 grams of solution. What is the concentration of the solution?
33%

10. Solubility - Concentration and Solubility
Solubility is a measure of how much solute can dissolve in a solvent at a given temperature.

11. Temperature and Solubility
- Concentration and Solubility
Temperature and Solubility
The solubility of the compound potassium nitrate (KNO3) varies in water at different temperatures.

12. Temperature and Solubility
- Concentration and Solubility
Temperature and Solubility
Reading Graphs:
At which temperature shown in the graph is KNO3 least soluble in water?
KNO3 is least soluble at 0ºC.

13. Temperature and Solubility
- Concentration and Solubility
Temperature and Solubility
Reading Graphs:
Approximately what mass of KNO3 is needed to saturate a water solution at 40ºC?
Approximately 65 g of KNO3 are needed to saturate a water solution at 40ºC.

14. Temperature and Solubility
- Concentration and Solubility
Temperature and Solubility
Calculating:
About how much more soluble is KNO3 at 40ºC than at 20ºC?
KNO3 is about twice as soluble at 40ºC as it is at 20ºC.

15. Temperature and Solubility
- Concentration and Solubility
Temperature and Solubility
Interpreting Data:
Does solubility increase at the same rate with every 20ºC increase in temperature? Explain.
No; the curve shows that solubility increases more with each 20ºC increase in temperature.

16. Building Vocabulary - Concentration and Solubility
After you read the section, carefully note the definition of each Key Term. Also note other details in the paragraph that contains the definition. Use all this information to write a meaningful sentence using the Key Term.
Key Terms:
Examples:
unsaturated solution
supersaturated solution
Key Terms:
Examples:
dilute solution
An unsaturated solution can continue to dissolve more solute.
A dilute solution is a mixture that has only a little solute dissolved in a certain amount of solvent.
concentrated solution
A supersaturated solution has more dissolved solute than is predicted by its solubility at the given temperature.
A concentrated solution is one that has a lot of solute dissolved in the same amount of solvent.
solubility
Solubility is a measure of how much solute can dissolve in a solvent at a given temperature.
saturated solution
A saturated solution contains so much solute that no more dissolves.

17. Properties of Acids and Bases
- Describing Acids and Bases
Properties of Acids and Bases
Litmus is an example of an indicator, a compound that changes color when in contact with an acid or a base.

18. Uses of Acids and Bases - Describing Acids and Bases
Acids and bases have many uses around the home and in industry.

19. Asking Questions - Describing Acids and Bases
Before you read, preview the red headings. In a graphic organizer like the one below, ask a what question for each heading. As you read, write answers to your questions.
Question
Answer
What is an acid?
An acid is a substance that tastes sour, reacts with metals and carbonates, and turns blue litmus paper red.
What is a base?
A base is a substance that tastes bitter, feels slippery, and turns red litmus paper blue.
What are uses of acids and bases?
Uses of acids include cleaning products, fertilizers, and car batteries; uses of bases include cleaning products, baking ingredients, and cement manufacturing.

20. Acids and Bases in Solution
The table lists some commonly encountered acids and bases.

21. Strength of Acids and Bases
- Acids and Bases in Solution
Strength of Acids and Bases
Strong acids and weak acids act differently in water. Hydrochloric acid is a strong acid. Acetic acid is a weak acid.

22. The pH Scale - Acids and Bases in Solution
A low pH tells you that the concentration of hydrogen ions is high. In contrast, a high pH tells you that the concentration of hydrogen ions is low.

23. Acid-Base Reactions - Acids and Bases in Solution
A reaction between an acid and a base is called neutralization. An acid-base mixture is not as acidic or basic as the individual starting solutions.

24. Acid-Base Reactions - Acids and Bases in Solution
Each salt listed in this table can be formed by the reaction between an acid and a base.

25. Previewing Visuals - Acids and Bases in Solution
When you preview, you look ahead at the material to be read. Preview Figure 21. Then write two questions that you have about the diagram in a graphic organizer like the one below. As you read, answer your questions.
Neutralization
Q. What is a neutral solution?
A. A neutral solution is one that has a pH close to 7.
Q. What is neutralization?
A. Neutralization is a reaction between an acid and a base.

26. Click the Video button to watch a movie about pH.
- Acids and Bases in Solution pH
Click the Video button to watch a movie about pH.

27. What Is Digestion? - Digestion and pH
Chemical digestion breaks large molecules into smaller ones.

28. pH in the Digestive System
- Digestion and pH
pH in the Digestive System
Foods are exposed to several changes in pH as they move through the digestive system.

29. At a pH near 2, stomach enzymes break down proteins.
- Digestion and pH
Sequencing
Sequence is the order in which a series of events occurs. As you read, make a flowchart that shows the sequence of changes in pH as food moves through the digestive system.
pH During Digestion
At a pH near 7, enzymes in the mouth start to break down carbohydrates.
At a pH near 2, stomach enzymes break down proteins.
At a pH near 8, enzymes in the small intestine complete the breakdown of carbohydrates, fats, and proteins.

30. Graphic Organizer Solutions Solutes Solvents Ions Molecules Water
are made of
Solutes
Solvents
dissolve in
dissolve to form
such as
Ions
Molecules
Water
conduct
do not conduct
Electricity