Common Laboratory Techniques (Inorganic Chemistry)

Place the glass tubing along the edge of the table and with the use of a triangular file, scratch the tubing at the point where it is to be cut. Do this in one direction only until a deep grove is made. Then hold the tubing with both hands and with the mark away from you, break the glass tubing. Make sure that both hands are close together on the side of the tubing opposite the mark.

• Fire Polishing Sharp Glass Edges

• Cutting a glass tubing

• Bending a Glass Tubing

• Measuring the Volume of a Liquid

Hold the cut end of the tubing over a Bunsen burner flame. Then rotate the tubing slowly until the glass starts to melt. (Do not touch the heated portion with your bare hands.)

• Fire Polishing Sharp Glass Edges

• Bending a Glass Tubing

• Heating Liquids in a Test tube

• Heating Solids in a Porcelain Crucible

Place a fish tail on top of the barrel of the Bunsen burner to spread out the non-luminous flame. Then heat the glass tubing at the desired point, rotating it slowly until it becomes soft. Remove the tubing from the flame end and bend.

• Heating Liquids in a Test tube

• Fire Polishing Sharp Glass Edges

• Heating of Chemical

• Bending a Glass Tubing

For reagent bottles with a screw cap, remove the cap and place it on the table, bottom up. Solid reagents should always be scooped out the bottle with a clean and dry spatula. Use paper strip when transferring reagents into a narrow-mouthed container. To obtain powdered samples from a wide-mounted container easily, tilt the reagent bottle and then slowly rotate it. Never put back any solid into the reagent bottle since this may contaminate the reagent.

• Handling of Reagents: Solid Reagents

• Handling of Reagents: Liquid Reagents

• Cutting a glass tubing

• Measuring the Volume of a Liquid

For a reagent bottle with glass stopper which cannot stand by itself, remove the stopper by pulling it out with the index and middle finger, palm facing upward. While the stopper is still between the two fingers, pick up the bottle and pour the liquid from the side opposite the table, otherwise the left on the lip may run down the side of the bottle and damage the label.

• Measuring the Volume of a Liquid

• Handling of Reagents: Liquid Reagents

• Handling of Reagents: Solid Reagents

• Heating Solids in a Porcelain Crucible

The apparatus commonly used for this is the graduated cylinder. The burette, pipette, volumetric flask, and medicine dropper can also be used. When measuring volume of liquid with a graduated cylinder, place the cylinder on a flat surface and read at eye level the lower meniscus for liquids which wet glass like water and the upper meniscus for liquids which wet glass like mercury

• Heating Solids in a Test Tube

• Measuring Mass

• Heating of Chemicals

• Measuring the Volume of a Liquid

When Heating Liquids in a Beaker or in an Evaporating Dish place the beaker or dish on a wire gauze supported in an iron ring attached to an iron ring stand or on a tripod. The wire gauze is used to produce uniform heating of the vessel and to prevent the vessel from cracking.

• Heating Liquids in a Test tube

• Heating of Chemicals

• Heating Solids in a Test Tube

• Heating Solids in a Porcelain Crucible

When heating ____ in a test tube, use a test tube holder. The test tube is held in a slanting position at about 45 degrees with the open end away from the persons working around you.

• Heating of Chemicals

• Heating Liquids in a Test tube

• Heating Solids in a Test Tube

• Heating Solids in a Porcelain Crucible

When heating ____ in a test tube clamp the test tube in an iron stand at about 45 degrees. The flame is applied slowly, moving it back and forth.

• Heating of Chemicals

• Heating Liquids in a Test tube

• Heating Solids in a Porcelain Crucible

• Heating Solids in a Test Tube

Solids may be heated into high temperature in a porcelain crucible which is supported by a clay triangle over an iron ring or tripod. The crucible is carefully placed on the clay triangle either in an upright or slanting position

• Heating of Chemicals

• Heating Liquids in a Test tube

• Heating Solids in a Test Tube

• Heating Solids in a Porcelain Crucible