2. 10 9 Days left until Benchmark Look at the lab handout with the pre-lab questions Catalyst: Find the Answer 1. You have 174 g of MnO 2 and you dissolve it in 4 L of H 2 O. What is the molarity of the solution? 2. What is the molar mass? How does a student find it? Answer

3. 10 9 Days Left Until The Benchmark Whip out your Homework! Let’s talk about results and discussion section Catalyst: 1.What is molar mass? 2.How do you you find molar mass?

4. Get your think on Class Meeting Time Let’s talk about labs/reports

5. Today’s Objectives I can identify the solute and solvent in a solution I can calculate the concentration of solution in terms of percent composition I can calculate the concentration of solution in terms of parts per million I can complete a lab on Kool-aid

6. Two More Ways to Calculate Concentration We can calculate the concentration of a solution two other ways: 1.Percent composition 2.Parts per million

7. Percent Composition Percent composition conveys the concentration in terms of percent of solute in a solution.

8. Steps to Calculate Percent Composition 1.Determine the mass of the solute 2.Determine the mass of the solvent. 3.Determine the total mass of the solute by adding the mass of the solute and the mass of the solvent (m solute +m solvent =m solution ) 4.Calculate the percent composition of the solution by dividing the mass of the solute by the mass of the solution.

9. Class Example A 4 g sugar cube (Sucrose: C 12 H 22 O 11 ) is dissolved in a 350 g of water. What is the percent composition by mass of the sugar solution that is created?

10. My Turn You have 5 moles of NaCl and you dissolve this in 500 g of water, what is the concentration of this solution in terms of percent composition?

11. Parts per Million The final concentration expression is parts per million Parts per million (ppm) is the number of grams of solute in 1 million grams of solution. It is a common unit used in environmental studies and pollutant concentration.

12. Calculating ppm Need to find mass of solute and mass of solvent and convert to grams.

13. Class Example Mercury poisoning is a very dangerous disease and humans often contract it by consuming fish that have been contaminated with mercury. The accepted safe level is 0.5 ppm of Hg in fish. What is the concentration of mercury in a fish if it has 0.0006 g of Hg in 500 g of H 2 O?

14. My Turn Nitrate (NO 3 ) is a very common polutant of groundwater. If you have 0.0308 g of NO 3 in a 700 g solution, then what is the concentration of NO 3 in ppm?

15. Enrichment! Carbon Monoxide (CO) is a common toxin that cannot be smelt and will kill you at concentrations above 400 ppm. If there are 1,500 g of CO in a 3 g sample of air, then is this a toxic ppm concentration of CO? To Do Work!

16. SUMMARIZE

17. Feeling Lucky? Cut out the dice and tape it together Roll the dice with your group and answer the question that it lands on. Do this until time is called

18. Work Time

19. Lab Reports Friday school list Discussion section must answer the 4 post-lab questions that were at the end of the handout Final draft is due December 7 th ! Failing to turn this in could lead to you getting an NP in the class!!!!!!!!!!!!!!! Side note: In science data is plural (e.g. you say “the data are” not “the data is”)

20. Not So Kool-Aid

21. I can experiment to determine the concentration, in molarity and percent composition, of known and unknown Kool- Aid solutions Lab Objective

22. Lab Conduct Follow the procedure that has been given to you Respect the equipment. It costs a lot of money to replace this stuff Use the chemicals in a responsible and safe way Clean up the space when you are done

23. Read the procedure again. Once completed begin assigning roles to group members

24. Mass By Difference

25. The Meniscus Measure at the bottom!

26. Volumetric Flasks

27. Lab Work Time

28. Race to the Finish Everyone will be starting on the left side of the room. If you get a question correct you move up one space. If you don’t get it correct you will not move. First person to get past station 8 will get hot cheetos

29. Questions 1.You have 15 g of KCl and you dissolve it in 3 L of water. What is the concentration in g/L? 2.You dissolve 1,220 g of KClO 3 in 1 L of water. What is the molarity of your final solution? 3.If all the water in 0.430 L of a 0.45 M NaCl solution evaporates, what mass of NaCl remains?

30. Questions 4. What is the molarity of a 450 mL solution that contains 200 grams of FeCl 2 ? 5. How many grams of KCO 3 are needed to make 200 mL of a 2.5 M solution? 6. 116 grams of KF is dissolved in enough water to make 4 L of solution. Calculate the concentration in ppm

31. Questions 7. 20 grams of NaOH is dissolved in enough water to make 1 liter of solution. Calculate the percent composition of the solution. 8. You eat fish that has 0.05 g of Hg in 2000 g of solution. What concentration (in ppm) of mercury did you just eat? 9. How many grams of MnO 2 are needed to make 5 liters of a 3 M solution?

32. Work Time

34. Closing Time Final draft of your lab report is due Wednesday December 7 th. Homework – Finish Concentration Worksheet – Last 2 problems BRING YOUR LAB HANDOUT WEDNESDAY!