Entry Task: April 27 th Friday

Entry Task: April 27thFriday Question: What is the molarity of 1.2 moles of calcium carbonate in 1.22 liters of water?

Agenda: • Sign off Discuss Concentration ws • Notes on Dilutions • HW: Concentration and Dilution ws

1. What is the percent concentration of 75.0 g of ethanol dissolved in 500.0 g of water? 75.0 g ethanol = % NaHCO3 500g water + 75 g ethanol 500g water+ 75 g ethanol= 575 g solution 75g NaHCO3 X 100 575 g solution = 13.0% ethanol solution

2. What is the percent concentration of benzene in a solution containing 14.2 grams of benzene in 28.0 grams of carbon tetrachloride? 14.2 g benzene = % solution 28.0 g CCl4+ 14.2 g benzene 28.0 g CCl4+ 14.2 g benzene = 42.2 g solution 14.2g benzene X 100 42.2 g solution = 33.6% solution

3. You have 1500.0 grams of bleach solution. The percent by mass of the solute sodium hypochlorite, NaOCl, is 3.62%. How many grams of NaOCl are in the solution? XgNaOCl = 3.62% NaOCl 1500 g solution Xg NaHCO3 = 3.62 100 1500 g solution 1500 X 3.2 = 5430 g 100 = 54.3g NaOCl

4. What is the percent by volume of ethanol in a solution that contains 35 ml of ethanol in 115 ml of water? 35 ml of ethanol = X% by volume ethanol solution 35 ml ethanol + 115 ml of water 35 ml ethanol X 100 150 ml solution = 23.3 %

5. What is the percent by volume of methanol in a solution that contains 25 ml of methanol in 75 ml of water? 25 ml of methanol = X% solution 25 ml ethanol + 75 ml of water 25 ml ethanol X 100 100 ml solution = 25.0 %

6. What is the molarity of an aqueous solution containing 40.0g of glucose (C6H12O6) in 1.5L of solution? 40 g of C6H12O6 1 mole of C6H12O6 180.16 g C6H12O6 0.222 moles of C6H12O6 1.5 L solution = 0.148 M

7. What is the molarity of a bleach solution containing 9.5 g of NaOCl per liter of bleach? 9.5 g of NaOCl 1 mole of NaOCl 74.44 g NaOCl 0.128 moles of NaOCl 1.0 L solution = 0.128 M

8. Calculate the molarity of 1.60 L of a solution containing 1.55 g of dissolved KBr. 1.55 g of KBr 1 mole of KBr 119.0 g KBr 0.013 moles of KBr 1.60 L solution = 0.00814 M

9. Calculate the number of moles of a 125 ml solution (convert to liters) 0.0500M Ba(OH)2. X moles of Ba(OH)2 = 0.0500 M 0.125 L solution (0.125 L)(0.0500) = 0.00625 moles

10. Calculate the number of grams of a 350 ml solution (convert to liters) 1.50 M Ba(OH)2. X moles of Ba(OH)2 = 1.50 M 0.350 L solution (0.350 L)(1.5) = 0.525 moles Ba(OH)2 0.525 molof Ba(OH)2 171.3 g Ba(OH)2 1 mole of Ba(OH)2 89.9 g Ba(OH)2

Moles of solute before dilution (i) Moles of solute after dilution (f) = Dilution Add Solvent = MfVf MiVi Dilution is the procedure for preparing a less concentrated solution from a more concentrated solution.

Dilutions: M1V1 = M2V2 • Molarity and Volume of the original solution = Molarity and Volume of the diluted solution. Make sure the volumes match!!!

Dilutions: M1V1 = M2V2 • P1. What volume, in milliliters of 2.00M calcium chloride (CaCl2) stock solution would you use to make 0.50 L of 0.300 M calcium chloride solution? Convert liters to milliliters. (2.00 M)( X) = (0.300 M )(500 ml) 150 = 75 ml 2.00M

Dilutions: M1V1 = M2V2 • P2. What volume of a 3.00M KI solution would you use to make 0.300 L of a 1.25 M KI solution? (3.00 M)( X) = (1.25 M )(0.300L) 0.375 = 0.125 L or 125 ml 3.00M

Dilutions: M1V1 = M2V2 • P3. If I add 25 ml of water to 125 ml of a 0.15 M NaOH solution, what will the molarity of the diluted solution be? (0.15 M)( 125 ml) = (X M )(150 ml) 18.75 = 0.125 M 150 ml

Use the rest of the period to work on homework

Entry Task: April 27 th Friday