Question

 

1) What are the advantages and disadvantages of microscale vs macroscale in the Organic laboratory?Think about some of the unique skills you have developed using microscale. Think about improved safety involved using microscale. Also think about things that were frustrating dealing with small quantities.

2) What are the advantages of writing your procedure immediately after performing an operation as opposed to writing it before doing the lab or even a day after doing the lab?

3) Why is it important to properly reference sources of information?

4) Define proper care and use of the following pieces of equipment or chemicals. autodelivery pipette, moisture sensitive chemicals ,salt plates toxic chemicals ,drying tubes ,melting point apparatus ,refractometer, thermometers, glassware ,syringes.

Answer 1

Organic chemistry

1) Some chemicals or compounds are needed to be prepared in large quantities as its usage is in excess. These are prepared by macroscale preparatory methods, wherein, large amounts of reactants are reacted to form large amounts of products. It is nenecssary to understand the safety measures associated when handling chemicals at large scale as the potential hazards assciated are also at a much larger extent. The chemicals are thus prepared in large amount and purification can be done to get the material. The economics of such processes are good and low process cost gives chemicals with low prices.

On the other hand speciality chemicals such as drugs and specific reagents are prepared at much smaller scale and are termed as microscale preparatory methods. The reactants are often very expensive and the products are also very expensive in these cases. Highly skilled trained people are needed for this technique. The waste generation in the process is very low when compared to the macroscale process. These are also on demand chemicals which are prepared when the need from the customer arises.

2) It is always adviced to write the procedure, observation and results of your experiment immediately after performing an operation so that no information goes missing or forgotten when say you write the procedure after a day of running the operation. Some things might slip out of mind at a later stage. Also the experiments should not be written before doing the experiment as observations associated with the expeirment can only be determined after doing the experiment.

3) It is important to properly reference source of information to know the safety associated with each chemical used in the expeirment and precautions may be taken before running an experiment.

4) Use of laboratory instrument.

autodelivery pipette is used to deliver a fized volume of solution, solvent or reagent at any given time.

moisture sensitive chemicals are handled in an inert atmosphere, mostly in a glove box, so to rpevent its degradation or reaction with mositure or air.

Drying tubes are used to keep water away from the reaction mixture. It is filled with drying agents such as CaCl2 which absorbs water from the air and keep the reaction safe from it. these are connected on top of the reflux condenser or to the reaction flask directly.

Melting poitn apparatus are used to determine the melting point of a solid compound. A capillary is filled with solid and heated at a constant rate to get a melting point.

Refractometer is used to determine refractive index of a sample in solution or neat samples. Various forms of refractometers are available in market and sensitivity of instruments vary depending upon the need of experimentalist.

thermometer are piece of instrument used to measure temperature. It is filled with mercury in ideal case and the rise and fall of mercury level depicts change in temperature.

Glass round bottom flask are used for running reactions, erlenmeyer flasks are used for collection of solutions, condenser used during reflux of reactions.

Syringes are used to deliver accurate volumes of liquid reagents, solvent or reactants into the reaction mixture. they come in disposable plastic or non-disposable glass types.