Bellringer: 12/16/2016 What is a homogeneous solution? What is a polar molecule? STOTD

Bellringer: 1/3/2017 See if you can determine what the following magnified photos are. Number your paper to 5. 1 2 3 4 5

The Answers:

Partner Review What is a homogeneous mixture? What is a solution? Provide 2 examples of homogeneous mixtures.

Solutions, Acids, and Bases Chapter 8

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

oxygen & carbon dioxide Solutions Example Solute Solvent Air oxygen & carbon dioxide (Gas) nitrogen Soda carbon dioxide Water (Liquid) Vinegar acetic acid Stainless Steel chromium and nickel (Solid) iron end

- + + 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

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

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

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

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

Solubility Solubility Curve What is the solubility of NH3 at 10 °C? 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

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

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

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

Solubility Supersaturated Solution Supersaturated Solution of KNO3 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 end

Bellringer: 1/4/2017 Use the solubility curve in your packet to answer the following questions: What temperature will dissolve 60 grams of NH3? I made a solution using 60 grams of sodium nitrate at 30 ⁰C. Did I make a saturated, unsaturated, or supersaturated solution? STOTD

Schedule and Updates 1/4/17 (Wed): Properties of solutions, Acids & Bases 1/5/17 (Thurs): Review & LAB!!! 1/6/17 (Fri): Review, Quiz, Packet due ~Weekend~ 1/9/17 (Mon): Light 1/10/17 (Tues): Electricity 1/11/17 (Wed): Mini Lab 1/12/17 (Thurs): Magnetism w/ Mini lab 1/13/17: Review, Quest, Packet due 1/16/17: No School (MLK day) 1/17-20/17: Review for Final Exam

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

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

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

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

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

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

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

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

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

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 turns blue end

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 Acid Base Water Salt- an Ionic Compound end

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

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