4.2: Types of Reports Handled in These Courses
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In the organic chemistry lab course there are two types of reports, which are all graded on a 100 point scale. One type comprises what’s commonly known as “lab reports,” that is, records referring to experiments performed in the lab. The other type refers to special assignments that are completed outside the laboratory. The format and contents of special assignments depends on their nature. They are specified in the syllabus, or at the time the assignment is made. Examples are the MSDS assignment in organic lab I, or the Chemical Literature assignments in organic lab II.
Lab reports, on the other hand, have a set format. They can be or two kinds, depending on whether they refer to experiments involving physical operations or chemical preparations (synthesis).
LAB REPORTS FOR PHYSICAL OPERATIONS, OR TECHNIQUE EXPERIMENTS
This type of report refers to lab work whose main objective is to learn, demonstrate, or perform a physical operation. Physical operations do not change the chemical nature of the substances involved. They are typically conducted as part of a synthesis and are frequently of two types:
1. Purification techniques, or separations. These operations are designed to isolate a pure substance from a mixture. Examples are crystallization, extraction, and distillation.
2. Characterization techniques. These operations are designed to return information that can be used to identify a substance. Examples are the determination of physical constants such as melting point, boiling point, or density, and instrumental techniques such as infrared (IR) spectroscopy. Sometimes these techniques are referred to as analytical techniques.
LAB REPORTS FOR CHEMICAL PREPARATIONS, OR SYNTHESIS
This type of report refers to experiments whose main goal is to prepare a pure substance from specific starting materials. This necessarily involves a chemical transformation, or reaction. In the simplest case, there is only one step. The starting materials are combined and a product forms. This product is isolated, purified, and characterized, producing the final outcome of the experiment. In a multistep synthesis, the product of the first step is used as a starting material in a second step, and so on, until a final product is obtained. No multistep syntheses are performed in organic lab I. Some two step syntheses are performed in organic lab II.