1. Warm-up Carbon dioxide has a solubility in water of 10g/L at 20 Celsius when the carbonation machine at Pepsi Co produces a pressure of 3 atm. One day the machine had a problem and could only produce 1.5 atm. What is the new solubility of carbon dioxide in the cans? S2 = S1x P2 = 10g/L x 1.5 atm = 5g/L P13 atm Half the pressure, half the solubility….

2. 16.2 The Concentration of Solutions Molarity

3. Molarity/Molar - M moles of solute dissolved in Liters of solution Molarity M = moles L Example: a solution is 5 Molar or has a Molarity of 5 M (Big M!) is the result of any of the following: 5 moles or 10 moles or 1 mole 1 Liter2 L 0.2 L Just divide numbers out!!!

4. Covert/calculate a) 90 ml = ______L 90/1000 = 0.09L b) 4 ml = ______ L 4/1000 = 0.004L c) 0.03 M express as moles/L 0.03 moles/L d) 2.5 M express as moles/L 2.5 moles/L

5. e) 3.4 moles in 5.6 L 3.4moles = 0.61 M 5.6 L f) 0.07 moles in 0.8 L 0.07moles = 0.09 M 0.8 L

6. Practice 1.How many moles of a salt are needed to prepare 4.6 L of a 2.5 M solution? moles= M x L = 4.6 L x 2.5 M = 11.5 moles 1.What is the molarity if 2.5 g of NaCl are dissolved in 0.1 L solution? 2.5 g x _1 mole __ x __1___ = 0.43 M 58.44g 0.1 L

7. How to make a solution: 100 ml of a 2 M glucose solution? ( MM glucose: 180.18 g/mole) 1.Calculation moles = M x L = 2 M x 0.1 L = 2 moles/L x 0.1 L = 0.2 moles 0.2 x 180.18 g= 36.04 g glucose How to do it: 1. Mass out glucose (balance) 2. Add only 75% of liquid because otherwise you suddenly have 110ml!!! Add about 75 ml, dissolve in a beaker 3. Transfer to cylinder and fill up to 100% liquid→ 100 ml close with parafilm swisherooo….(cylinder)

8. Warm-up Make 500 ml of a 0.8 M Silver nitrate solutions

9. Make 1.5 L of a 5 M NaCl solution Calculate and list steps how to actually make it!

10. Dilution of Stock Solutions Stock solutions are Are concentrated solutions (5x – five times concentrated, 10 x…) Diluting is easier than making a new solution from scratch Formula M1 x V1 = M2 x V2 1 is concentrated, 2 is diluted solution

11. Practice 1 You need 100 ml of a 0.5 M solution from a 2M stock, how much volume do you need from the stock solution? V1 = M2V2 = 0.5M x 0.1L = 0.025 L = 25 ml M12 M How to do it: 1.Measure out 25 ml of stock solution 2.Fill up to 100 ml 3.Swisheroo…..is this fast or not?

12. You need to make 0.2L of a 0.3 M solution from a 6 M stock solution. Do calculation, list steps

13. You need to make 150 ml of 0.25 M solution from a 2 M stock Do math List steps

14. Make 500 ml of a 0.2 M solution from a 2 M stock solution. Do math

15. Percent solutions Do not need molar masses and are easier to make Commonly used when solute is liquid %(m/m) “percent mass” or %(w/w) percent weight older version %(v/v) “percent volume” %(m/v) “percent mass per volume”

16. Percent Mass - % (m/m) (sometimes called %(w/w) percent weight) Need only balance! Water as a solvent has the following mass… H2OH2O 1 L = 1000ml=1000 g 1 ml =1g % (m/m) = mass of solute x 100% mass of final solution Final solution is solvent + solute together!!!!

17. Percent Mass: % (m/m) 50 g salt dissolved in 500 g solution 250 g sugar added to 1L of water Need to make 500 g of a 2% (m/m) solution

18. Percent volume - % (v/v) Used if solute is a liquid % (v/v) = volume of solute x 100% volume of total solution Volumes can be in L or ml, but: both (solvent and solute) have to be the same unit!

19. Practice 50 ml alcohol added to 100 ml water 29 ml of alcohol dissolved in a 1.5 L solution Need to make 500 ml of a 2% (v/v) aqueous alcohol solution. Assume alcohol available is 100%

20. Percent mass per volume- (%m/v) Easy alternative to a Molar solution Practice: % (m/v) = mass of solute x 100% volume of total solution Do: Make 1 L of a 5% (m/v) NaCl solution.

21. Warm-up You have to make 200 ml of a 3% (m/v) sucrose solution Calculate List steps

22. Test Review Journal Use the following molecules to answer questions. List all that apply! A.Sucrose C 12 H 22 O 11 B.MgCl 2 C.Oil D.HCl E.He 1.Which of the molecule(s) dissolve in water? 2.Which molecule(s) is/are electrolytes? 3.Which molecule(s) dissolve in Methylene chloride? 4.Which molecule(s) is/are polar?

23. Journal PropertiesWater Rubbing alcohol/acetone/ methylene chloride Surface tension Vapor pressure Polarity Boiling point assign high/low behind the terms below to indicate the behavior of water and rubbing alcohol