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14 oktober 2022

Chemical/Laboratory Techniques Video Series

This set contains 14 YouTube videos, created by Dr Niek Eisink and Dr Tjalling Canrinus of the Faculty of Science and Engineering of the University of Groningen. These instructional videos all deal with different laboratory techniques that are highly relevant for chemistry students and researchers, as well as others who work with chemical techniques in their day-to-day work. The following 14 topics are discussed in this set: Recrystallization Reflux setup Distillation Extraction Gloves Volumetric flasks Vacuum filtration UV-Vis spectrophotometer Thin Layer chromatography (TLC) Column chromatrography Schlenk line Greasing glass joints Micropipettes Rotary evaporator The videos aim to be useful tools for current students and staff, professionals who are looking for a refresher on fundamental laboratory techniques, and other educators who want use these videos in their teaching and lab instruction.

Video

Tjalling Canrinus, Niek Eisink

14 oktober 2022

Chemical/Laboratory Techniques: Extraction

This open video (CC-BY-NC-SA) was created by chemistry teachers of the Faculty of Science and Engineering of the University of Groningen for use in the lab at their faculty. The description of for the video reads the following: Liquid-liquid extraction is a technique in which two non-miscible solvents are employed to separate a mixture of compounds based on their relative solubility in one of the two phases. Extraction is often used for the primary isolation of a product from the reaction mixture. Typically, the two phases are water (polar phase) and an organic solvent (apolar phase). It is, however, also possible to use two organic phases such as the combination of acetonitrile (polar phase) and pentane (apolar phase) for the extraction. The polar compound dissolved into the polar phase while the apolar compound dissolve into the apolar phase.

Video

Tjalling Canrinus, Niek Eisink

14 oktober 2022

Chemical/Laboratory Techniques: Gloves

This open video (CC-BY-NC-SA) was created by chemistry teachers of the Faculty of Science and Engineering of the University of Groningen for use in the lab at their faculty. The description of for the video reads the following: Gloves are commonly used pieces of personal protection equipment (PPE), besides lab glasses and lab coats. The gloves are meant to protect your hands against accidental spillage and should only be worn when working with hazardous chemicals and taken off as soon as possible when your gloves are exposed to chemicals while conducting experiments in the lab.

Video

Tjalling Canrinus, Niek Eisink

14 oktober 2022

Chemical/Laboratory Techniques: Distillation

This open video (CC-BY-NC-SA) was created by chemistry teachers of the Faculty of Science and Engineering of the University of Groningen for use in the lab at their faculty. The description of for the video reads the following: Distillation is based on the principle that liquids have different boiling points and that the temperature of a mixture does not increase above the lowest boiling point. By heating the solution to the first boiling point of a liquid in the mixture, we can condense the vapours of this liquid in a separate flask. By continuously changing the flask whenever the thermometer indicates a different boiling point we can separate a mixture of liquids into pure liquids. Certain compounds have a very high boiling point or decompose when heated. By reducing the pressure you can lower the boiling point and separate the liquids (vacuum distillation). Certain liquids form an azeotrope and can’t be separated from each other by distillation. This video contains royalty-free music from Bensound.com, obtained via their free license (song: Tenderness - Benjamin Tissot; https://www.bensound.com/royalty-free-music/track/tenderness; License: https://www.bensound.com/terms-and-conditions). Please provide proper attribution to this source if you reuse sections of this OER video containing this music.

Video

Tjalling Canrinus, Niek Eisink

14 oktober 2022

Chemical/Laboratory Techniques: Recrystallization

This open video (CC-BY-NC-SA) was created by chemistry teachers of the Faculty of Science and Engineering of the University of Groningen for use in the lab at their faculty. The description of for the video reads the following: Recrystallization is based on the principle that the solubility of most solids in a solvent increase with increased temperature. The setup used is explained in the following video: Building a reflux setup (https://youtu.be/kylffAXH-ls). Recrystallization involves dissolving the material to be purified (the solute) in a minimal amount of appropriate hot solvent. As the solvent slowly cools, the solution becomes saturated with the solute and the solute crystallizes out (reforms a solid). As the crystal develops, impurities are excluded from the crystal lattice, thereby completing the purification process. The crystals can then be collected, washed, and dried. This video contains royalty-free music from Bensound.com, obtained via their free license (song: Tenderness - Benjamin Tissot; https://www.bensound.com/royalty-free-music/track/tenderness; License: https://www.bensound.com/terms-and-conditions). Please provide proper attribution to this source if you reuse sections of this OER video containing this music.

Video

Tjalling Canrinus, Niek Eisink

14 oktober 2022

Chemical/Laboratory Techniques: Micropipettes

This open video (CC-BY-NC-SA) was created by chemistry teachers of the Faculty of Science and Engineering of the University of Groningen for use in the lab at their faculty. The description of for the video reads the following: Micropipettes allow for very precise control over the amount of liquid that you add or remove from samples and reactions. They come in a wide range of volumes and styles. Micropipettes are commonly used for aqueous solutions in biological experiments but can also be used for pipetting organic solvents. In this case however, solvents with a low boiling point can easily start to drip due to build up of pressure inside the tip. Organic solvents can also damage the plastics inside the micropipettes. It is therefore easier to use calibrated micro syringes for organic solvents instead of micropipettes.

Video

Tjalling Canrinus, Niek Eisink

14 oktober 2022

Chemical/Laboratory Techniques: Rotatory evaporator

This open video (CC-BY-NC-SA) was created by chemistry teachers of the Faculty of Science and Engineering of the University of Groningen for use in the lab at their faculty. The description of for the video reads the following: The rotatory evaporator is a designated vacuum distillation machine. You can attach single necked round bottom flask containing your solvent you want to remove. The machine can rotate this flask (increasing the surface area of the liquid inside) while the flask is also heated using a water bath, generally set to 40 °C. The machine is connected to a vacuum pump and pressure regulator. By setting the pressure to the required level to boil off the solvent at 40 °C, you can quickly remove the solvents. Any other volatile component at the set pressure and temperature will also be removed. This video contains royalty-free music from Bensound.com, obtained via their free license (song: Tenderness - Benjamin Tissot; https://www.bensound.com/royalty-free-music/track/tenderness; License: https://www.bensound.com/terms-and-conditions). Please provide proper attribution to this source if you reuse sections of this OER video containing this music.

Video

Tjalling Canrinus, Niek Eisink

14 oktober 2022

Chemical/Laboratory Techniques: Reflux setup

This open video (CC-BY-NC-SA) was created by chemistry teachers of the Faculty of Science and Engineering of the University of Groningen for use in the lab at their faculty. The description of for the video reads the following: To increase the rate of reactivity, reactions are often performed at elevated temperatures. However, simple organic compounds and solvents often have a low boiling point. As such, most organic chemicals are quite volatile, and if heated they will evaporate and be lost. The solution to this problem is to heat the reaction mixture under reflux. Reflux involves heating the chemical reaction for a specific amount of time, while continually cooling the vapour that is produced back into its liquid form. A condenser is used for cooling the vapour. The setup demonstrated in this video can be extended upon with various other pieces of glassware to suit the needs of your reaction.

Video

Tjalling Canrinus, Niek Eisink

14 oktober 2022

Chemical/Laboratory Techniques: Column Chromatography

This open video (CC-BY-NC-SA) was created by chemistry teachers of the Faculty of Science and Engineering of the University of Groningen for use in the lab at their faculty. The description of for the video reads the following: Column chromatography is based on the same principle as Thin Layer Chromatography (https://youtu.be/u1iOf8hhdv8) but enables the separation of different components from a reaction mixture on a preparative scale. While using Silica or Aluminium oxide as the stationary phase (the most commonly applied), the mobile phase is an organic solvent or a mixture of organic solvents. The stationary phase consists of an adsorbing material, which is used as a powder instead of being attached to glass or aluminium foil as in TLC. The stationary phase is packed into the column and the reaction mixture is added to the top part of the packed column. By running the mobile phase (eluent) through the column, the components will elute from the column at different times. When using silica as a stationary phase, it is possible to apply (air) pressure to the column, causing the mobile phase to run faster and the chromatography to be quicker (flash chromatography). This video contains royalty-free music from Bensound.com, obtained via their free license (song: Tenderness - Benjamin Tissot; https://www.bensound.com/royalty-free-music/track/tenderness; License: https://www.bensound.com/terms-and-conditions). Please provide proper attribution to this source if you reuse sections of this OER video containing this music.

Video

Tjalling Canrinus, Niek Eisink

14 oktober 2022

Chemical/Laboratory Techniques: Volumetric flasks

This open video (CC-BY-NC-SA) was created by chemistry teachers of the Faculty of Science and Engineering of the University of Groningen for use in the lab at their faculty. The description of for the video reads the following: A volumetric flask is calibrated to contain a particular volume of solution at 20 °C when the bottom of the meniscus is adjusted to the centre of the mark on the neck of the flask. The temperature of the container is relevant because both liquid and glass expand when heated. Volumetric flasks are used to make solutions with known concentration. This is achieved by either dissolving a known amount of solid/liquid or by diluting a solution with a prior set concentration.

Video

Tjalling Canrinus, Niek Eisink