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 prelab based on section 4.1 of the green book and the following
procedure
• Procedure is on the next slide
Procedure
Experiment 4.1
Dissolving a solid in a liquid
• 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:
1. 2 test tubes
2. 5 g of Sodium Chloride (NaCl)
3. 5 g of Sodium Nitrate (NaNO3)
4. 2 stoppers
8. Burner
5. Evaporating dish
6. Watch glass
7. Burner stand
Lab 4.3: Comparing
concentrations of solutions
• 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
water
3. Put the a stopper on the test tube and shake
vigorously
4. Mass a clean dry evaporating dish and watch glass
5. 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:
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 dryness
9. Allow the evaporating dish to cool
10.Mass the evaporating dish with its contents and watch glass
(system after heating)
11.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
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
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
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
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.