Chapter 6 Solutions, Acids, and Bases

1. Chapter 6Solutions, Acids, and Bases • Chapter Preview: • 6.1) Solutions and Other Mixtures: • Heterogeneous Mixtures • Homogeneous Mixtures: • 6.2) Dissolving and Solubility: • The Dissolving Process • Water: A Common Solvent • Concentration • 6.3) Acids, Bases, and pH: • What are Acids? • What are Bases? • How Acidic Is and Acid? • Neutralization Reaction • 6.4) Acids and Bases In the Home: • Cleaning Products • Other Household Acids and Bases

2. Section 6.1: Solutions and Other Mixtures • Objectives: distinguish between homogeneous mixtures and heterogeneous mixtures. • Compare and contrast the properties of solutions, colloids, and suspensions. • Identify ways to separate different kinds of mixtures.

3. Heterogeneous Mixtures: • A heterogeneous mixture, such as fruit salad is not the same throughout. • Suspension: a mixture that looks uniform when stirred or shaken that separate into different layers when it is no longer agitated. Particles size of about 1000 nm. • Colloid: a mixture of very tiny particles of pure substances that are dispersed in another substance but do not settle out of the substance. Particles size from 1 to 100 nm in diameter.

4. Heterogeneous Liquid – Liquid Mixtures: • When oil is mixed with vinegar to make salad dressing, two layers form. • Immiscible: when two liquid don’t mix. • Emulsion: any mixture of immiscible liquids in which the liquids are spread throughout one another.

5. Homogeneous Mixtures: • Homogeneous Mixtures not only look uniform, they are uniform. • For example: salt water, kool –aid, and lemonade, etc.

6. Solutions are homogeneous mixtures: • Solution: a homogeneous mixture of two or more substances uniformly spread throughout a single phase. • Solute: the substance that dissolves in a solution. • Solvent : the substance that dissolves the solute to make a solution.

7. Miscible liquids mix to form solutions. • One way to separate miscible liquids is by a process called distillation. For example water mixes with isopropanol to make a solution of rubbing alcohol.

8. Section 6.1 Summary Report • A heterogeneous mixture is a nonuniform blend of two or more substances. • The particles in a suspension soon settle out of the mixture. • The dispersed particles in a colloid are smaller and do not settle out. • An emulsion is a colloid in which liquids that normally do not mix are spread throughout one another. • A homogeneous mixture, or solution, is a uniform blend of two or more substances. • In a solution, the solute is dissolved in the solvent.

9. Section 6.2Dissolving and Solubility • Describe how a substance dissolves in of its solubility, molecular motion, and solute-solvent interactions. • Identify several factors that affect the rte at which a substance dissolves. • Relate the structure of water to its ability to dissolve many different substances. • Distinguish between saturated, unsaturated, and supersaturated solutions.

10. The Dissolving Process • According to the kinetic theory, the water molecules in each glass of tea are always moving. • Some moving water molecules collide with sugar crystals. • When this happens, energy is transferred to the sugar molecules at the surface of the crystal.

11. Solutes with a larger surface area dissolve faster. • Stirring or shaking a solution helps the solute dissolve faster. • Solutes dissolve faster when the solvent is hot. • Not every substance dissolves. • Soluble in water • Insoluble in water

12. Water: A Common Solvent • Two-thirds of Earth’s surface is water. • The liquids you drink are mostly water. • Water is colorless and tasteless. • Water is sometimes called the universal solvent.

13. Characteristics of Water: • The structure of water helps it dissolve charged particles: • “Like dissolves like”: • Water can dissolve many substances, but there are many others it can’t dissolve. • For example, olive oil doesn’t dissolve in water, and neither does gasoline. That because its components are non-polar, meaning their molecules do not have partial charges on opposite ends.

14. Concentration • You can make a solution by dissolving sodium acetate in water. But how much sodium acetate do you need to add? • Concentration: the quantity of solute dissolved in a given quantity of solution.

15. Types of Solutions: Unsaturated Solution: a solution that is able to dissolve more. Saturated solution: a solution that cannot dissolve any more solute at the given condition.

16. Supersaturated solution: a solution holding more dissolved solute than is specified by its solubility at a given temperature.

17. Section 6.2 Summary Report • The larger the surface area a solute has, the faster it will dissolve. • Stirring or shaking the solution dissolves solutes faster. • Heating a solvent also dissolves solutes faster. • So many substances are soluble in water that it is sometimes called the universal solvent. • An unsaturated solution can dissolve more solute. • A saturated solution cannot dissolve any more solute. • A solute’s solubility is exceeded in a supersaturated solution.

18. Section 6.3 Acids, Bases, and pH • Objectives: • Compare and contrast acids and bases. • Relate the pH of a solution to the concentration and strength of dissolved acid or base. • Identify the products of neutralization reactions.

19. What are Acids? • Acid: a substance that donates hydrogen ions, H+, to form hydronium ions, H3O+, when dissolved in water. • Sour • Conduct electricity and heat • Turn litmus paper from blue to red • Examples; lemon, lime, dill pickles, etc.

20. What are Bases? • Base: a substance that either contains hydroxide ions, OH-, or reacts with water to form hydroxide ions. • Bitter • Conductors of electricity and heat. • Turn litmus paper from red to blue.

21. How Acidic Is an Acid and How Basic Is a Base? • pH: a measure of the hydronium ion concentration in a solution. • The pH values correspond to the concentration of hydronium ions. • Small differences in pH values mean larger differences in hydronium ion concentration.

22. Neutralization Reactions: • Neutralization reaction: a reaction in which hydronium ions from an acid and hydroxide ions from a base react to produce water molecules. • Note: strong acids and bases react to form water and a salt. • Note: some acid-base reactions do not result in neutral solutions.

23. Section 6.3 Summary Report • Acids are sour, corrosive substances that form hydronium ions when dissolved in water. • Bases are bitter, slippery substances that either contain hydroxide ions or form them when dissolved in water. • Indicators are substances that change color depending on whether a solution is acidic, basic, or neutral. • Neutral solutions have a pH of 7, acidic solutions have a pH of less that 7, and basic solutions have a pH of greater than 7. • A neutralization reaction occurs when hydronium ions and hydroxide ions react to form water molecules.