Make up Labs 4.1 and 4.3. Purpose, Hypothesis, and Materials should come from your own pre- lab...

Make up Labs4.1 and 4.3

• 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


• 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:

1. 2 test tubes 5. Evaporating dish2. 5 g of Sodium Chloride (NaCl) 6. Watch glass 3. 5 g of Sodium Nitrate (NaNO3) 7. Burner stand4. 2 stoppers

8. Burner


• Procedure:1. Mass 5 grams of sodium chloride (A) or 5 grams of

sodium nitrate (B)2. Place substance in a test tube that contains 5 ml of

water3. Put the a stopper on the test tube and shake

vigorously4. Mass a clean dry evaporating dish and watch glass5. Pour the liquid into the evaporating dish (be careful

not to pour any of the undissolved solid in the evaporating dish).


• Procedure:6. Mass the evaporating dish liquid and watch glass together

(system before heating)7. Place the watch glass on top of the evaporating dish.8. Heat to dryness9. Allow the evaporating dish to cool10.Mass the evaporating dish with its contents and watch glass

(system after heating)11.Calculate the concentrations of the 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 g

Mass of system after heating 69.46 g

Mass of dissolved solute 4.02 g

Volume of solvent 5 ml

Concentration of solution .646 g/ml


Data table for Sodium Nitrate (Solution B)

Mass of evaporating dish and watch glass

55.95 g

Mass of system before heating 66.05 g

Mass of system after heating 60.5 g

Mass of dissolved solute 5.55 g

Volume of solvent 5 ml

Concentration of solution .765 g/ml

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.

Make up Labs 4.1 and 4.3. Purpose, Hypothesis, and Materials should come from your own pre- lab...

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