Chapter Preview Questions

1. Chapter Preview Questions • 1. A solution is an example of a • a. homogeneous colloid. • b. heterogeneous colloid. • c. homogeneous mixture. • d. heterogeneous mixture.

2. Chapter Preview Questions • 1. A solution is an example of a • a. homogeneous colloid. • b. heterogeneous colloid. • c. homogeneous mixture. • d. heterogeneous mixture.

3. Chapter Preview Questions • 2. Magnesium sulfide and aluminum fluoride are • a. ionic compounds. • b. molecular compounds. • c. covalent electrons. • d. radioactive elements.

4. Chapter Preview Questions • 2. Magnesium sulfide and aluminum fluoride are • a. ionic compounds. • b. molecular compounds. • c. covalent electrons. • d. radioactive elements.

5. Chapter Preview Questions • 3. When dissolved in water, ionic compounds • a. conduct electricity. • b. make the water cloudy. • c. form double and triple bonds. • d. do not conduct electricity.

6. Chapter Preview Questions • 3. When dissolved in water, ionic compounds • a. conduct electricity. • b. make the water cloudy. • c. form double and triple bonds. • d. do not conduct electricity.

7. Chapter Preview Questions • 4. When dissolved in water, molecular compounds • a. conduct electricity. • b. make the water cloudy. • c. form double and triple bonds. • d. do not conduct electricity.

8. Chapter Preview Questions • 4. When dissolved in water, molecular compounds • a. conduct electricity. • b. make the water cloudy. • c. form double and triple bonds. • d. do not conduct electricity.

9. Suppose you dissolve a • teaspoon of salt in a glass of • water. Is it possible to recover • the salt from the water? • Explain. What are some characteristics of acids and bases?

10. Section 1: Understanding Solutions • Standard 8.5.d Students know physical processes including freezing and boiling, in which a material changes form with no chemical reaction.

11. Section 1: Understanding Solutions • What are the characteristics of a solution? • A solution has the same properties throughout. It contains solute particles (molecules or ions) that are too small to see. • Solutions: • Contain a solvent, which dissolves the other substances • Contain at least 1 solute, which is dissolved by the solvent • Dissolving one substance into another is a physical change. • The substances retain their original properties.

12. Section 1: Understanding Solutions • What are the characteristics of a colloid? • A colloid contains larger particles than a solution. The particles are still too small to be seen easily, but are large enough to scatter a light beam. • Examples: • milk • fog • mayonnaise • whipped cream

13. Section 1: Understanding Solutions • What are the characteristics of a suspension? • A suspension does not have the same properties throughout. It contains visible particles that are larger than the particles in solutions or colloids.

14. Particles in a Solution • When a solution forms, particles of the solvent surround and separate the particles of the solute.

15. Liquid water solution Effects of Solutes on Solvents • Solutes lower the freezing point and raise the boiling point of a solvent. Solute particles make it harder for water molecules to form crystals. Water molecules need more energy to boil when a solute is present. Solid (frozen) water

16. Section 1 Quick Quiz • How would a solute affect the boiling point of water? • The boiling point will be the same at the freezing point. • The water will not boil. • The water will boil at a lower temperature. • The water will boil at a higher temperature. • Answer: D – The water will boil at a higher temperature.

17. Section 1 Quick Quiz • When a solute is added to a solvent, the freezing point of the solution is • the same as the freezing point of the solute. • higher than the freezing point of either substance alone. • lower than the freezing point of either substance alone. • the same as the freezing point of the solvent. • Answer: C – lower than the freezing point of either substance alone.

18. Section 2: Concentration and Solubility • Standard 8.5.d Students know physical processes including freezing and boiling, in which a material changes form with no chemical reaction.

19. Concentration • How is concentration measured? • To measure concentration, you compare the amount of solute to the total amount of solution. • A concentrated solution has a lot of solute dissolved in a certain amount of solvent. • A dilute solution has only a little solute dissolved in a certain amount of solvent. • Concentration can be measured as the percent of solute in solution by volume or mass.

20. 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. Calculating a Concentration

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

22. Practice Problem A solution contains 15 ounces of solute dissolved in 60 ounces of solution. What is the concentration of the solution? 25% Calculating a Concentration

23. Practice Problem A solution contains 40 grams of solute dissolved in 200 grams of solution. What is the concentration of the solution? 20% Calculating a Concentration

24. Solubility • Solubility is a measure of how much solute can dissolve in a solvent at a given temperature. • If you can continue to dissolve more solute, you still have an unsaturated solution. • If no more solute will dissolve, you have a saturated solution.

25. Factors Affecting Solubility • What factors affect the solubility of a substance? • Factors that affect the solubility of a substance include pressure, the type of solvent, and temperature. • An increase in pressure increases the solubility of gases. • Ionic and polar compounds usually dissolve in polar solvents – “like dissolves like” • The solubility of most solids increases as temperature increases. • Gases become less soluble in a liquid when the temperature of the liquid goes up.

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

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

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

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

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

31. Section 2 Quick Quiz • When you add so much solute that no more dissolves, you have a • suspension. • unsaturated solution. • saturated solution. • neutralization. • Answer: C – saturated solution.

32. Section 2 Quick Quiz • What happens to the concentration of sugar in maple sap as the sap is boiled? • The concentration of sugar increases. • The concentration of sugar remains constant. • The concentration of sugar becomes 0%. • The concentration of sugar decreases. • Answer: A – The concentration of the sugar increases.

33. Section 2 Quick Quiz • If two unidentified solids of the same texture and color have different solubilities in 100 grams of water at 20°C, you could conclude that • they are the same substance. • they are different substances. • they have different melting points. • their solubilities will be the same if the water temperature is increased. • Answer: B – they are different substances

34. Section 2 Quick Quiz • A measure of how well a solute can dissolve in a solvent at a given temperature is that substance’s • concentration. • saturation point. • acidity. • solubility. • Answer: D - solubility

35. Section 2 Quick Quiz • What is one way to increase the solubility of sugar in water? • Heat the water. • Chill the water. • Increase the amount of sugar. • Decrease the amount of water. • Answer: A – Heat the water

36. Section 2 Quick Quiz • A beaker contains 120 grams of salt water solution. The salt water has 36 grams of salt dissolved in it. What is the concentration of the solution? • 36% • 30% • 72% • 24% • Answer: B – 30%

37. Section 3: Describing Acids and Bases • Standard 8.5.e Students know how to determine whether a solution acidic, basic, or neutral.

38. Properties of Acids and Bases • What are the properties of acids? • What are the properties of bases? • An acid tastes sour, reacts with metals and carbonates, and turns blue litmus paper red. • A base tastes bitter, feels slippery, and turns red litmus paper blue.

39. 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.

40. Uses of Acids and Bases • Acids and bases have many uses around the home and in industry.

41. Uses of Acids and Bases • Acids and bases have many uses around the home and in industry.

42. Uses of Acids and Bases • Acids and bases have many uses around the home and in industry.

43. Uses of Acids and Bases • Acids and bases have many uses around the home and in industry.

44. Uses of Acids and Bases • Acids and bases have many uses around the home and in industry.

45. Uses of Acids and Bases • Acids and bases have many uses around the home and in industry.

46. Uses of Acids and Bases • Acids and bases have many uses around the home and in industry.

47. Uses of Acids and Bases • Acids and bases have many uses around the home and in industry.

48. Uses of Acids and Bases • Acids and bases have many uses around the home and in industry.

49. Uses of Acids and Bases • Acids and bases have many uses around the home and in industry.

50. Uses of Acids and Bases • Acids and bases have many uses around the home and in industry.