Properties Of Ionic And Covalent Substances Lab (Page 2 of 2) in pdf

3. Set the hot plate on high.

4. Observe and record the order of melting of the solids in your data table (1, 2, 3)

5. After observations are complete, CAREFULLY remove the aluminum foil boat with crucible tongs

and allow it to cool completely. Dispose of the boat in the garbage.

Part 2: Test of Solubility

Generally, ionic solids are only soluble in very polar solvents (such as water). Polar covalent molecules

will dissolve in polar solvents and non-polar covalent molecules will only dissolve in non-polar solvents

(“like dissolves like”).

1. Test the solubility of each of the three solids by placing a “scoop” of each solid in a 100mL labeled

beaker and filling it half way with de-ionized water. (Avoid cross contamination in beakers!)

2. Stir the mixture and observe and record if the solid dissolved in the water. (DO NOT DUMP IT

OUT!)

Part 3: Test of Conductivity

When an ionic compound dissolves, the ions are often pulled apart by the polar water and become free to

move about in the solvent. The movement of these charged ion particles allows for the conduction of an

electric current. Undissolved solids or polar covalent solids do not form these ions in water and thus do

not allow for conduction.

1. Insert the metal electrodes of your conductivity tested into each of the three mixtures you created in

the 100 mL beakers. Using a paper towel, clean the leads to avoid cross contamination between tests.

2. Observe and record if conductivity was detected in each solution. A positive result is indicated by a

steady green light.

Data Table

Name of Compound

Order of Melting

Soluble in water?

Soluble in hexane?

Conducts in water?

Sugar

Salt

Wax

Yes

Conclusion:

Based upon your observations, place each substance into one of the following categories: ionic

compound, polar covalent compound, or non-polar covalent compound. Based on the data given for the

solubility in hexane, is hexane a polar or non-polar covalent solvent? Explain.

Discussion:

Discuss the reasons why you placed each substance in its category. Provide evidence from the melting

point, solubility, and conductivity tests you did in the lab.

Properties Of Ionic And Covalent Substances Lab Page 2