Make up Labs 4.1 and 4.3

Experiment 4.1 Dissolving a solid in a liquid Purpose, Hypothesis, and Materials should come from your own pre- lab based on section 4.1 of the green book and the following procedure Procedure is on the next slide

Experiment 4.1 Dissolving a solid in a liquid Procedure Collect materials Add water to test tubes A groups - 20 ml B groups – 5 ml Add 0.3 g of orange solid Place stopper on test tube and shake If the solid completely dissolved, add 0.3 g more Record observations and data Keep track of total orange solid added January 21, 2014

Experiment 4.1 Dissolving a solid in a liquid Observations How many grams did you add to the 20 ml test tube? How many grams did you add to the 5 ml test tube? How did the colors compare in each test tube throughout the experiment? Conclusion Restate hypothesis, was it supported, what evidence shows this, what are possible sources of error?

Lab 4.3: Comparing concentrations of solutions Pre Lab – Due Tuesday January 28

Lab 4.3: Comparing concentrations of solutions Purpose: To compare the concentration of saturated solutions Hypothesis: None required for this experiment Materials: 2 test tubes 5. Evaporating dish 5 g of Sodium Chloride (NaCl) 6. Watch glass 5 g of Sodium Nitrate (NaNO3) 7. Burner stand 2 stoppers 8. Burner

Lab 4.3: Comparing concentrations of solutions Procedure: Mass 5 grams of sodium chloride (A) or 5 grams of sodium nitrate (B) Place substance in a test tube that contains 5 ml of water Put the a stopper on the test tube and shake vigorously Mass a clean dry evaporating dish and watch glass Pour the liquid into the evaporating dish (be careful not to pour any of the undissolved solid in the evaporating dish).

Lab 4.3: Comparing concentrations of solutions Procedure: Mass the evaporating dish liquid and watch glass together (system before heating) Place the watch glass on top of the evaporating dish. Heat to dryness Allow the evaporating dish to cool Mass the evaporating dish with its contents and watch glass (system after heating) Calculate the concentrations of the solutions.

Lab 4.3: Comparing concentrations of solutions Data table for Sodium Chloride (Solution A) Mass of evaporating dish and watch glass 67.95 g Mass of system before heating 73.48 Mass of system after heating 69.46 Mass of dissolved solute 4.02 Volume of solvent 5 ml Concentration of solution .646 g/ml

Lab 4.3: Comparing concentrations of solutions Data table for Sodium Nitrate (Solution B) Mass of evaporating dish and watch glass 55.95 g Mass of system before heating 66.05 Mass of system after heating 60.5 Mass of dissolved solute 5.55 Volume of solvent 5 ml Concentration of solution .765 g/ml

Lab 4.3: Comparing concentrations of solutions Sodium Chloride (A) (g/ml) Sodium Nitrate (B) (g/ml) 0.63 0.872 .65 .83 .96 .962 .586 .634 .646 .765 .714 .894

Lab 4.3: Comparing concentrations of solutions Conclusion Write a conclusion about which solution had the greater concentration and why.