Kool-Aid & Solutions Calculations

Objective: – Today I will be able to: Explain the properties of solutions Calculate the concentration of solutions using the equation for molarity, molality, dilution, and mole fraction. Create varying concentrations of Kool-Aid using solution principles Evaluation/Assessment: – Informal assessment – monitoring student progress as they complete the lab – 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: Kool-Aid Lab Elaborate: Molarity Calculations Elaborate: Dilution Calculations Elaborate: Molality & Mole Fraction Evaluate: Exit Ticket

Warm-Up What are the equations for molarity, dilution, molality, and mole fraction? Explain the process of creating a solution and then diluting the solution.

Objective Today I will be able to: – Explain the properties of solutions – Calculate the concentration of solutions using the equation for molarity, molality, dilution, and mole fraction – Create varying concentrations of Kool-Aid using solution principles

Agenda Warm – Up Kool-Aid Lab Molarity Calculations Dilution Calculations Molality & Mole Fraction Exit Ticket

Announcements Brief solutions calculations quiz Wednesday!

Preparing Solutions

Kool-Aid Lab Today you are making a 0.3 M Kool-Aid solution, again! You will also be randomly assigned different diluted concentrations to create Lets look over the lab sheet!

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 – Ex: 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)

Molality Molality = moles of solute/kg of solvent Practice: What is the molality of a solution in which 3.0 moles of NaCl is dissolved in 1.5 kg of water?

Mole Fraction Χ i = moles of i total moles

Mole Fraction Example mole of NaCl is dissolved into grams of pure H 2 O. What is the mole fraction of NaCl? – Steps to solve the problem Convert mass of H 2 O  moles of H 2 0 Add the moles of H 2 O and NaCl together to get the total number of moles in the solution Divide the moles of NaCl by the total number of moles Answer: No units because it is a ratio!

Exit Ticket 3-2-1: Based off today’s lesson write down – 3 things you learned – 2 questions you still have – 1 comment you want Mr. Klotz to know about today’s lesson