Achievement Task

Scenario

A chemical spill at Sarnia Southern High School disrupted traffic and class schedules Monday as Sarnia Fire Department fire-fighters cleaned the contaminated area. A four-litre container of an unknown solid crystalline substance broke open after being placed on a lab table. The chemical was being used by two students in the science wing of the school, according to Lt. Bond, spokesperson for the Fire Department. The accident occurred at about 10:30 a.m. The students in the lab left the room, closed the door behind them and called the authorities after the accident. The building was then evacuated.   Bond said there were no injuries and that it was fortunate that no one was hurt. "The folks here knew what they were doing," said Cova Lent, a FD battalion chief. "They did a good job."

As a fire department employee, you are accountable to the public for documenting the materials you used, the procedures you designed and the observations that you noted. This is important because an investigation of the incident will likely follow the clean up.

Part A: Research

Use the background material found on the first page of this issue and your text references to prepare for this task.

Part B: Testing and Inquiry

You were the chemical spill specialist at the local fire department. You were aware that the types of agents that you use to clean up a spill depend on the type of chemical that was spilt.

You carefully collected a small sample of the solid in a test tube and brought it back to your lab in order to determine how to proceed further with the clean up. The first step you took was to determine the type of bonding in the crystalline solid by performing at least three tests. By figuring the bonding type you could then safely choose the agents/materials that were necessary to clean up the chemical from the science lab.

The tests that you perform are the following:

Solubility:
Chemical compounds have a wide range of solubilities in various solvents. Adding a small amount of solid sample to a small amount of solvent in a test tube and stirring can test the solid's solubility. If solid remains then we would say the substance is insoluble or only slightly soluble in that solvent. You will test the solubility of the compound in water, alcohol, and oil. Keep in mind which solvent is the most polar and which is non-polar.)

Effect of Heat:
Place a small amount of the unknown solid on a crucible lid and heat with the flame of a Bunsen burner. Compounds that do not decompose and have a high melting point (e.g., KCl or NaCl) will be unchanged in the flame.

Test(s) of your own design and choice:
Research at least one other test that would help you determine the bonding type in the solid.

Part C: Analyze and Reflect

You need to justify your decisions with data. Your platoon chief required a formal lab report with detailed observations recorded in a table and an explanation of your observations in terms of what type of bonding was present in the spilt solid.

Part D: Communicate

Your final task, as spills specialist, is to draw up a written conclusion about what you have learned about your solid and discuss what additional tests could have been performed if equipment was available and what results you would expect for your solid.