As you come in,  Pass up the Calories in a Chip Lab.  Get paper, pencil, and calculator ready for notes on calculations.  NOTE: Solubility Graph Quiz tomorrow!  Pass up the Calories in a Chip Lab.  Get paper, pencil, and calculator ready for notes on calculations.  NOTE: Solubility Graph Quiz tomorrow!

Concentration  Concentration - the amount of solute in a specific amount of solvent  Molarity (M)  Molality (m)  Molarity is the most common unit used to report the concentration of a solution in a laboratory setting.  Concentration - the amount of solute in a specific amount of solvent  Molarity (M)  Molality (m)  Molarity is the most common unit used to report the concentration of a solution in a laboratory setting.

Molarity  The number of moles of solute per liter of solution.  Write a mathematical equation to represent the definition of molarity.  Explain your equation. (A)  Agree or disagree. (B)  The number of moles of solute per liter of solution.  Write a mathematical equation to represent the definition of molarity.  Explain your equation. (A)  Agree or disagree. (B)

Molarity Equation moles of solute Molarity = Liters of solution Example: Calculate the molarity of 0.4 mol NaCl dissolved in 1.6 L solution. Answer: 0.25 M NaCl moles of solute Molarity = Liters of solution Example: Calculate the molarity of 0.4 mol NaCl dissolved in 1.6 L solution. Answer: 0.25 M NaCl

5 minute Independent Practice  You will have a 5 minute Partner time next. 8-) Practice Problems: grams of potassium nitrate is dissolved in enough water to make mL of solution. What is the molarity? 2.Calculate the number of grams of solute needed to prepare 2.0 L of 2.0M nitric acid. 3.Challenge: Give the concentrations of all the ions in each of the following solutions: M Co(NO 3 ) M FeCl 3  You will have a 5 minute Partner time next. 8-) Practice Problems: grams of potassium nitrate is dissolved in enough water to make mL of solution. What is the molarity? 2.Calculate the number of grams of solute needed to prepare 2.0 L of 2.0M nitric acid. 3.Challenge: Give the concentrations of all the ions in each of the following solutions: M Co(NO 3 ) M FeCl 3

5 Minute Partner Review  Check your Practice Problem answers with your partner.  Are your chemical formulas written correctly?  Did you make the appropriate conversions before plugging into the molarity equation?  What are your questions? (Write them down, and prepare to ask with our large group.)  Check your Practice Problem answers with your partner.  Are your chemical formulas written correctly?  Did you make the appropriate conversions before plugging into the molarity equation?  What are your questions? (Write them down, and prepare to ask with our large group.)

Molarity - Correct Answers 1.Potassium nitrate = KNO g KNO 3 is converted to 0.20 mol KNO 3. The volume of 250.0mL is converted to.250L. The Molarity = 0.8 M KNO 3 2.Nitric Acid = HNO 3 4mol of HNO 3 is calculated by plugging into the Molarity equation. The mass of four moles of HNO 3 is 252 grams. 1.Potassium nitrate = KNO g KNO 3 is converted to 0.20 mol KNO 3. The volume of 250.0mL is converted to.250L. The Molarity = 0.8 M KNO 3 2.Nitric Acid = HNO 3 4mol of HNO 3 is calculated by plugging into the Molarity equation. The mass of four moles of HNO 3 is 252 grams.

Molality  The number of moles of solute per kilogram of solvent.  Write a mathematical equation to represent the definition of molality.  Explain your equation. (B)  Agree or disagree. (A)  The number of moles of solute per kilogram of solvent.  Write a mathematical equation to represent the definition of molality.  Explain your equation. (B)  Agree or disagree. (A)

Molality Equation moles of solute Molality = kilograms of solvent Example: What is the molality of a solution that contains 2.3 moles of glucose dissolved in g of water? Answer: 4.6 m moles of solute Molality = kilograms of solvent Example: What is the molality of a solution that contains 2.3 moles of glucose dissolved in g of water? Answer: 4.6 m

5 Minute Independent Practice  Practice Problems: 1.Find the molality of 131 g Ba(NO 3 ) 2 dissolved in g H 2 O. 2.How many grams of sodium chloride must dissolve in grams of water to make a 0.50 molal solution?  Practice Problems: 1.Find the molality of 131 g Ba(NO 3 ) 2 dissolved in g H 2 O. 2.How many grams of sodium chloride must dissolve in grams of water to make a 0.50 molal solution?

Molality - Correct Answers g Ba(NO 3 ) 2 is converted to 0.50 moles, and g of H 2 O is converted to kg H 2 O. The molality is 0.67 m Ba(NO 3 ) grams of H 2 O is converted to kg of H 2 O. The equation is solved to give moles NaCl, which converts to 21.9 grams g Ba(NO 3 ) 2 is converted to 0.50 moles, and g of H 2 O is converted to kg H 2 O. The molality is 0.67 m Ba(NO 3 ) grams of H 2 O is converted to kg of H 2 O. The equation is solved to give moles NaCl, which converts to 21.9 grams.

Preparing a Solution Lab  Today, you will be writing a lab procedure to prepare a solution of a specific Molarity.  Purpose  Materials  Procedure  Calculations  Each group will be preparing a different solution.  Today, you will be writing a lab procedure to prepare a solution of a specific Molarity.  Purpose  Materials  Procedure  Calculations  Each group will be preparing a different solution.

GroupMolarity (500 mL) Solute 10.05NaCl C 12 H 22 O Na 2 SO Na 2 SO NH 4 Cl NH 4 Cl C 12 H 22 O 11