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Unit 2: Describing Chemical Change Notebook Labs

View Scoring Rubrics (link coming soon)


The following items should be in the Unit 2 portion of your notebook.  They should be clearly organized and easy to find.  Use an organizational system and label all work. Each lab will be graded separately.  All lab grades will be entered into the gradebook.


Lab DCC1. Chemical Properties

Question:
What are the chemical properties of hydrochloric acid and copper chloride?

Purpose:
To describe the chemical properties of hydrochloric acid and copper chloride.

Safety:
Sodium hydroxide and hydrochloric acid are corrosive chemicals with the potential of causing considerable damage to the eyes and the skin. Ammonium hydroxide vapors can be both a lung and an eye irritant. Cupric chloride is toxic when ingested. Magnesium and zinc dust are flammable.  Handle all solids with a forceps or micro-spatula. Wear googles at all times.  Think safety!

Disposal:
Paper and solid wastes should never be poured in the drain, but removed from the well with forceps and placed in the provided waste containers.  Liquid solutions from the well plate can be thoroughly rinsed down the drain. Once thoroughly cleaned, the well plate should be propped at a mild angle and upside down against an object to allow to air dry.

A complete lab write-up includes a Title, a Purpose, a Data section, and a Conclusion/Discussion.  The Data section should be extensive - providing a thorough documentation of the chemicals which were mixed and the results of the tests which were performed (temperature, litmus tests, etc.) and the observations (color change, bubbles, precipitate formation, etc.) which were made. The Conclusion/Discussion should describe the chemical properties of the two substances and cite the observations which provide the supporting evidence; it should be lengthy, thorough and well-organized.





Lab DCC2. Conservation of Mass

Question:
Is mass conserved during a chemical change?

Purpose:
To determine if mass is conserved during a chemical change.

Safety:
Silver nitrate solution is toxic and will stain skin and clothing upon contact. Cupric chloride is toxic when ingested.  Wear googles at all times. Think safety!

Disposal:
The precipitate should be filtered and brought to the teacher for safe disposal.  Remaining chemicals can be drained and thoroughly rinsed.  The lab table should receive a good cleaning with a several wet paper towels before leaving the lab.

A complete lab write-up includes a Title, a Purpose, a Data section, and a Conclusion/Discussion.  The Data section should include observations and measured data, recorded to the proper number of significant figures. The Conclusion/Discussion should include the answer to the question posed in the Purpose of the lab (as usual) and should identify the supporting evidence.  A percent difference calculation should be performed based on the initial and the final mass.  See equations on the Lab Reporting page.





Lab DCC3. Chemical Drop-out

Question:
What precipitate (if any) will perform when two aqueous solutions of ionic salts are mixed?

Purpose:
To determine which combination of ions will precipitate in double replacement reactions and to use a model to explain the results.

Safety:
Of course, goggles must be worn at all times.  Other than NaCl(aq), all solutions are skin and eye irritants and toxic by ingestion.  Silver solutions can stain skin and clothing;  avoid exposure;  if exposed, rinse thoroughly. 

Disposal:
Before leaving the lab, the transparency should be thoroughly rinsed in the sink.  Lab tables should be thoroughly rinsed and left to air dry before leaving lab. Wash your hands thoroughly with soap and water before leaving the lab.

A complete lab write-up includes a Title, a Purpose section, a Data section, and a Conclusion/Discussion section.  The Data section should include an organized table which documents the result of mixing all combination of ions;  the presence or absence of a precipitate should be indicated in each cell of the table.  In addition to the table, for each instance of a precipitate, chemical formula of the precipitate should be indicated; be sure to label the cell (e.g., 1A or 3F). Finally, pick 4 precipitation reactions (but no more than two per row) and write the net ionic equations (including aq and s state symbols) for each.  The Conclusion/Discussion should include a paragraph in which you describe in some degree of detail how to use solubility rules to predict whether a precipitate will form and what the chemical formula will be for that precipitate. Include one example and one non-example of a precipitation reaction from your data section and apply your model of solubility to explain the results in words.





Lab DCC4. Classifying Chemical Reactions

Question:
For each of a collection of mixed reactants:  what are the products of their reaction?  What balanced chemical equation can be written to describe their reaction?  How can the reaction be classified?

Purpose:
For each of a collection of mixed reactants: to identify the products of the reaction by name and chemical formula, to write the balanced chemical equations and to classify the reaction according to its type.

Safety:
Of course, goggles must be worn at all times. Directions should be followed carefully. Ethyl Alcohol is flammable and a dangerous fire risk. Keep hair and clothing away from flames and other sources of ignition. Addition of denaturant to the alcohol has made it poisonous;  it is unfit for ingestion. Hydrochloric acid and sodium hydroxide solutions are corrosive. Magnesium metal is a flammable solid and zinc metal may contain flammable dust. Copper(II) chloride is toxic by ingestion.

Disposal:
Undissolved solids should never be poured down the drain; instead, they should be placed in a garbage can.  All other solutions can be poured in the sink and thoroughly rinsed down the drain.

A complete lab write-up includes a Title, a Purpose section, a Data section, and a Conclusion/Discussion section.  The Data section should include the results of your observations recorded in the provided table;  observations should be clear, extensive, and complete.  The Conclusion/Discussion section should include the balanced chemical equation for each reaction and classify each reaction according to type.  This section will be limited on writing and include mostly balanced chemical equations and a reaction type classification.  View Directions and Data Table.












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