Wednesday Bellringer: 5/22/2019

1. Wednesday Bellringer: 5/22/2019 Throw Back Questions!! • What is a homogeneous solution? • What are valence electrons? • What does it mean to dissolve? • STOTD Wed- Friday: Notes on Solutions, Acids, Bases Monday:No School, Memorial day Tuesday: Review & Lab Prep Wednesday: Lab/Test: Your lab grade will be your test grade.

2. Solutions, Acids, and Bases Chapter 8

3. Solutions Solution Homogeneous Mixture 1 substance dissolves in another Can be in any state of matter (solid, liquid, gas) 2 parts: Solute The substance that is dissolved Solvent The substance that does the dissolving end

4. Solutions end

5. Solutions Polar Molecule Valence electrons are NOT shared equally 1 side is negative 1 side is positive Water (H2O) - The Oxygen holds the electrons more Hydrogen gets the electrons less + + end

6. Solutions Nonpolar Molecule Valence electrons ARE shared equally No charge Carbon dioxide (CO2) • Valence electrons are pulled toward each side • Spreading out the charge. • Tug-of-War end

7. Solutions Polar Molecules DO NOT dissolve Nonpolar Molecules ex) Oil and Water don’t mix! Remember the phrase: “Like Dissolves Like” Polar dissolves polar Nonpolar dissolves nonpolar end

8. Solutions How is something Dissolved? When you put a solute into a solvent: The solvent surrounds the solute The solvent separates solute 1 molecule at a time In Ionic Compounds: solvent separates the cations from the anions Covalent Molecules: solvent breaks molecules into smaller pieces end

9. Solubility Solubility The maximum amount of a solute that dissolves in a certain amount of a solvent Usually written as: At 50 °C, the solubility of KNO3 is 80 g. You can dissolve up to 80 g of KNO3 in 100 g of water end

10. Solubility Solubility Curve Graph of a compound’s solubility at different temps. What is the solubility of NH3 at 10 °C? ~ 69 g of NH3 / 100 g of H2O 60 g of NH4Cl can be dissolved in 100 g of water at what temperature? ~ 70 °C end

11. Solubility Depending on the amount of solute dissolved, solutions are classified as: Unsaturated Saturated Supersaturated end

12. Solubility Unsaturated Solutions Has less than the maximum amount of solute dissolved Can still dissolve more solute You have dissolved 60 g of KNO3 in 100g of water Found BELOW the line on the solubility curve Unsaturated Solution of KNO3 end

13. Solubility Saturated Solution Has the maximum amount of solute dissolved Cannot dissolve anything else You have dissolved 80 g of KNO3 in 100g of water Found ON the line of the solubility curve Saturated Solution of KNO3 end

14. Solubility Supersaturated Solution Has more than the maximum amount dissolved You have dissolved 130 g of KNO3 in 100 g of H2O Found ABOVE the line on the solubility curve Supersaturated Solution of KNO3 end

15. Solubility To create a supersaturated solution: Dissolve as much solute as possible Heat the solution and dissolve more solute Allow the solution to cool slowly Supersaturated Solutions are very sensitive Shaking/stirring or adding more solute, will make the extra solute fall out of solution end

16. Thursday Bellringer: 5/23/19 Use the solubility curve in your packet to answer the following questions: • What temperature will dissolve 80 grams of KNO3? • How many grams of KCl will dissolve at 90 degrees Celsius? • STOTD

17. Properties of Solutions • Conductivity • Ionic Compounds(aq) and Acids(aq) conduct electricity • Electrolytes • Covalent Molecules will NEVER conduct electricity • Nonelectrolytes • Pure water WILL NOT conduct electricity end

18. Pure Water- No flow of electricity Pure NaCl- No flow of electricity Water + NaCl- Electricity end

19. Properties of Solutions • Electrolytes • Conduct when dissolved • Strong Electrolyte • Good Conductor • Completely Dissolves into IONS • Weak Electrolyte • Poor Conductor • Small Amount Dissolves into IONS • Nonelectrolyte • Does NOT Dissolve into IONS end

20. Properties of Solutions Freezing Point Dissolving a substance lowers the freezing point Salt put on icy roads Boiling Point Dissolving a substance raises the boiling point Radiators have ethylene glycol dissolved in water end

21. Rates of Dissolving 4 ways to make something dissolve faster: 1. Increase concentration of solvent Add more solvent 2. Increase the surface area Grind it up 3. Stir the solution 4. Increase the temperature end

22. Acids and Bases Acid A compound that produces the hydronium ion (H3O+) when dissolved in water H2O + HCl H3O+ + Cl- Chemical formulas start with an “H” HCl, H2SO4, H3PO4 Remember: H+ = H3O+ end

23. Acids and Bases 3 general properties of acids: 1. Sour Taste Like vinegar or spoiled milk 2. Reactive with Metals Mixed with metals they will produce hydrogen gas 3. Color change in indicators 0-6 on pH scale Phenolphthalein turns colorless Litmus paper turns red end

24. Acids and Bases Base A compound that produces the hydroxide ion (OH-) NaOH Na+ + OH- Chemical formulas end with an “OH” NaOH, Mg(OH)2, Al(OH)3 end

25. Acids and Bases 3 general properties of bases: 1. Bitter Taste Like dark chocolate and Cough syrups 2. Slippery Feeling The base is dissolving your skin cells 3. Color change in indicators 8-14 on the pH scale Phenolphthalein turns pink/red Litmus paper turnsblue end

26. Chemical Reaction Neutralization Reaction between an acid and a base This is a Double-Replacement Reaction Produces a salt and water HCl + NaOH H2O + NaCl H2SO4 + Mg(OH)2  2H2O + MgSO4 Base Water Salt- an Ionic Compound Acid end

27. Strength of Acids and Bases pH scale A measure of the hydronium ion (H3O+) concentration More H3O+ = More Acidic = Lower pH Neutral Basic Acidic end

28. Strength of Acids and Bases Acids/Bases are classified as strong or weak How much they break down to form H+ and OH- ions When you mix a weak acid/base with the salt from the neutralization reaction: You Form a Buffer A solution that keeps the same pH value when an acid/base is added to the solution end

29. Friday Bellringer:5/24/2019 • Fill in the table with the correct missing Info: • STOTD • Lab/Test Tomorrow!!

30. Acid & Base Lab Pre-Lab Activity Make a T Chart with information about Acids on one side and Bases on the other. You need 4 facts on each side. Acid Base

33. Conclusion: • Write a paragraph that includes that following: • What did you do in this experiment? • You cannot say “Because Mrs. Shaw told me to” • What was the goal of this experiment? • What data did you collect? Include specific results from your experiment. • Ex) When A and F were mixed together the litmus paper turned _____, the pH paper turned______. • Identify the unknowns based on your data. • Ex) Unknown A is ____ because the litmus paper turned ____ and the phenolphthalein turned ______.

34. Bellringer: • What do you know about acids? • What do you know about bases? • STOTD Monday: Notes on Acids and Bases Tuesday: Review & Lab Prep Wednesday: Lab/Test: Your lab grade will be your test grade. Thursday & Friday: Notes on Waves and Light

35. Bellringer: • STOTD in your Notebook • Get your Acid & Base Lab papers out • Put all bookbags at the front of the room • Grab an apron & goggles