Intro to Solutions Molarity Calculations

Evaluation/Assessment: Objective: Today I will be able to: Explain the properties of solutions Calculate the concentration of solutions using the equation for molarity. Evaluation/Assessment: Informal assessment – monitoring student progress as they complete the practice Formal assessment – analyzing student responses to the classwork and exit ticket. Common Core Connection Build Strong Content Knowledge Make sense of problem and persevere in solving them Look for and express regularity in repeated reasoning

Lesson Sequence Evaluate: Warm – Up Engage and Explore: Research Solutions Vocabulary, Design Poster Explain: Solutions Vocabulary Presentations Elaborate: Molarity Calculations Evaluate: Exit Ticket

Warm - Up As you enter, choose your new seat for 4th quarter. What is a solution? What are some examples of a solution? What are the two types of mixtures? Write one example of each type of mixture. What type of mixture is a solution?

Objective Today I will be able to: Explain the properties of solutions Calculate the concentration of solutions using the equation for molarity

Homework Finish Molarity Calculations

Agenda Warm-Up Solutions Vocabulary Research Design Vocabulary Poster Solutions Vocabulary Presentations Molarity Calculations Exit Ticket

Solutions Vocabulary Activity Directions

Solutions Vocabulary Activity Directions OVERVIEW Today you will teach the class vocabulary from the solutions unit Each group will be assigned a section to take notes and research the vocabulary Groups will design a poster Groups will present the poster to the class As the groups present, you will record the information presented as your notes

Solutions Vocabulary Research and Poster Designing You have 15 minutes to research the vocabulary and design a poster. Write large and neatly so the poster can be read by your peers during your presentation

Presentations Each group will have 3-4 minutes to share the information that they found. The class will record the information on the solutions notes sheet

Mr. Klotz’s Solutions notes for those students who are absent

Review: What is a solution? Homogeneous mixture; ability of one substance to dissolve another substance

Components of Solutions What is a solvent? Solvent – the dissolving medium - Water = aqueous solution - Alcohol = tincture What is a solute? Solute – what is being dissolved When a solute dissolves in a solvent, the molecules of solute enter the spaces between the molecules of the solvent

Components of Solutions Like dissolves like – polar and most ionic substances dissolve in polar solvents - Interactions occur between the solute and solvent molecules - Nonpolar dissolves in nonpolar - Nonpolar solutes are NOT attracted to nonpolar solvents - They depend on random motion in the solution process

Factors effecting the rate of solubility Size of solute Stirring rate Adding Heat

Concentrations of Solutions An increase in temperature of a solution generally INCREASES the solubility of a SOLID in a LIQUID An increase in temperature of a solution generally DECREASES the solubility of a GAS in a LIQUID

What is a nonelectrolyte What is an electrolyte? A solution that conducts electricity What is a nonelectrolyte A solution that does not conduct

Types of Solutions Solid in a solid – jewelry Liquids in liquids (miscible) – antifreeze Liquids in solids – dental filling Gas in a gas – air Gas in a liquid – soda Solid in a liquid – sea water

Miscible – layers that dissolve freely in each other Immiscible – layers that do not dissolve in each other

Concentrations of Solutions Unsaturated – less than the maximum of amount of solute Saturated – maximum amount of solute dissolved Supersaturated – more than the maximum amount of solute dissolved due to heating and rapid cooling

Concentration of a Solution Molarity (M) – moles of solute/liters of solution

Preparing Solutions

Preparing Solutions Use Molarity calculations Use a 1 L volumetric flask - calculate the formula weight of the compound - Dilute compound with water to the 1 L mark on the flask - Invert solution to mix - Creates a 1 M concentration solution

Dilution of a more concentrated solution to a less concentrated one Preparing Solutions Dilution of a more concentrated solution to a less concentrated one V old x M old = V new x M new

Things that Remind Mr. Klotz of Solutions (but are not) Suspension - a mixture from which some particles will slowly settle when left alone for a period of time (muddy water) - Particles that settle can be filtered out

Things that Remind Mr. Klotz of Solutions (but are not) Colloid – heterogeneous mixture of two or more substances that appears to be a solution Smoke (solid in gas), marshmallow (gas in a solid), whipped cream (gas in a liquid)

Things that Remind Mr. Klotz of Solutions (but are not) Tyndal Effect – allows you to distinguish between a true solution and a colloid Shine a light on a true solution, and the light is invisible Shine a light on a colloid, and you will be able to see the light beam as it reflects off the relatively large solute particles (headlights in fog)

Molarity Calculations Complete the calculations at your desk. Ask Mr. Klotz for help if you have questions. Questions not completed in class will become homework

Exit Ticket How would you prepare 1.5 L a 2.0 M solution from a stock solution of 6.0M HCl?