2. Chemistry 20

3.  A standard solution is any solution whose concentration is accurately known.  Dilution involves the addition of solvent to a solution in order to decrease its concentration.  For aqueous solutions, water is added to dilute the solution. This increases the overall volume without affecting the amount of dissolved solute.

5.  The stock solution is the more concentrated solution that is being diluted. It is generally a standard solution.  By diluting a solution carefully and with accurate measurements, the dilute solution will also be a standard solution.

6. 300 mL of water is added to 17.2 mL of 5.14 mol/L HBr (aq). Calculate the resulting concentration.

7. 0.278 mol/L

8. For a class experiment, a teacher must prepare 1.00 L of 0.170 mol/L sulfuric acid, H 2 SO 4(aq). This acid is usually sold as a 17.8 mol/L concentrated solution. How much of the concentrated solution should be used to make a new solution with the correct concentration?

9. 9.55 mL

10. 30.0 mL of a stock solution of CaCl 2(aq) is diluted to a total volume of 500.0 mL. The dilute solution is analyzed and found to have a concentration of 15.8 mmol/L. What was the molarity of the stock solution?

11. 0.263 mol/L

12. The two common ways of preparing a standard solution include:  dissolving a measured mass of pure solute in a certain volume of solution  diluting a stock solution by adding a known volume of solvent

13. When dissolving a measured mass of pure solute, the steps to follow are:  Calculate the mass of solute that will need to be measured out.  Measure out this mass of solute accurately with an electronic balance.  Dissolve the solute in a minimum volume of water.  Transfer solution into a volumetric flask that is half-filled with water.  Fill the volumetric flask with water up to the calibration line.  Stopper the flask and mix the solution.  http://www.youtube.com/watch?v=XMtm4h VCGWg http://www.youtube.com/watch?v=XMtm4h VCGWg

14. How would a 0.180 mol/L solution of lithium nitrate be properly prepared by dissolving the solid chemical?

15. mass of LiNO 3 = 12.411 g

16. When diluting a stock solution, the steps to follow are:  Calculate the volume of stock solution that will need to be measured.  Measure out this volume of solution accurately with a pipette.  Transfer solution into a volumetric flask that is half-filled with water.  Fill the volumetric flask with water up to the calibration line.  Stopper the flask and mix the solution.  http://www.youtube.com/watch?v=kMDC4 vNEoVo http://www.youtube.com/watch?v=kMDC4 vNEoVo

17. How would a 0.220 mol/L solution of acetic acid be properly prepared by dilution of a 3.50 mol/L stock solution?

18. 62.9 mL

19.  Dilution and Standard Solutions Practice Questions  Solutions Quiz Wednesday