Graduated Cylinder And Volumetric Flask

The image is Pixabay property

One of the tools used to measure liquids in the lab is a graduated cylinder. Graduated cylinder has tube shaped with a holder on the bottom as a glass holder. Graduated cylinder size assortment among which 5 ml, 10 ml, 20 ml, 25 ml, 50 ml, 100 ml, 500 ml, 1000 ml, 2000 ml, and so forth. Graduated cylinder has an accuracy under the burette, volumetric pipette, and graduated pipette. Graduated cylinder has a scale from top to bottom, from a scale of 0 (zero) ml to its highest volume, for example 10 ml graduated cylinder, has a scale of 0 ml to 10 ml. At the top there is a glass teapot spout such as water, to facilitate the discharge of the graduated cylinder.

Graduated cylinder is made of glass or plastic for their intended use. Graduated cylinders made of glass can be used for all kinds of liquids such as acids, bases, salts, and distilled water. But graduated cylinders made of plastic can only be used for neutral liquids such as saline and distilled water. It is better not to use plastic graduated cylinder to take acid or base for plastic could possibly react to acid or base. How to use a graduated cylinder that is clean glassware washing with water and soap, brush the inside of the graduated cylinder with tube brush, then rinse with water. Dry the graduated cylinder or rinse with distilled water 3 times. Rinse the graduated cylinder with a liquid to be measured 3 times, so that the concentration of the liquid is not reduced because it is mixed with distilled water.

The use of graduated cylinders very easy, much easier than burette or pipette, ie pour the liquid into a graduated cylinder, remove excess liquid, then measure the desired fluid.  For example the fluid is needed as much as 5 ml, then pour the liquid into a graduated cylinder 5 ml, then discard the liquid if it exceeds a scale of 0 ml. If the difficulty to get a liquid that fits on a scale of 0 ml, using a pasteur pipette. Pasteur pipette is a tool shaped glass small tube that pointed lower end and the upper end of a rubber such as a small oval balloon. Pasteur pipette doesn’t have scales. Rinse the pasteur pipette with distilled water 3 times and then with the liquid 3 times.

How to get distilled water or a liquid with a pipette that is the input end of a glass pipette into distilled water or liquids, squeeze the bubble gum and then release. When the rubber bubble is released, the liquid will rise into the pipette. Lift the pipette from the liquid and then wipe with a tissue or blotting paper, try with one wipe, the outside of the pipette becomes dry. Then place the pipette in a graduated cylinder, 1 cm above the liquid. And push the bubble gum slowly, this will cause a discharge from a pipette in the form of liquid droplets.

If the fluid is aligned with a scale of 0 ml. Stop droplets and reinsert the residual liquid in the pipette into the bottle of fluid. Then pour the liquid from the graduated cylinder into the next container. Wash the graduated cylinder with water back, then soap and water. Then dry. Do not forget to wash the pipette which has been used by opening the bubble gum, and a small pipe pipette was washed with water, then with soap, and finally with water. And dry it.

In addition to graduated cylinders, glassware others are used to obtain or create a solution in accordance with the desired volume accurately that volumetric flask. Volumetric flask used to prepare a solution or liquid whose concentration can be known for certain. This solution is made from solid or liquid substances whose concentration is concentrated. Volumetric flask had various sizes of 5 ml, 10 ml, 20 ml, 25 ml, 50 ml, 100 ml, 200 ml, 250 ml, 500 ml, 1000 ml and so on. Volumetric flask made of glass, the bottom is round but not perfectly round, and there is a pipe extending into it. At the top of the pipe there is a line that marks the boundary of the volume of the volumetric flask.

Volumetric flask must first be cleaned with water and soap, rub the inside of the tube by using a brush, the last rinsed again with water. Volumetric flask should not be dried by putting in the oven, because it expands and the volume will be increased so that the volume, then measurement becomes inaccurate.

Before use, rinse the volumetric flask 3 times with distilled water. For example, to create na2so4 salt solution, weigh as much as 1.2345 grams of salt na2so4 with weighing bottle using an analytical balance. Take a clean volumetric flask and then place on top of the funnel glass (insert the tip of the funnel into the volumetric flask). Among the funnel and flask, place tissue so that air can get out of the volumetric flask when inserting liquid into it. Open the weighing bottle cap and rinse 3 times with distilled water, fill the rinse water weighing bottle cap into the weighing bottle, do not let the rinse water that falls out.

Enter the distilled water into the bottle weigh up to ¾ of the weighing bottle. Stir this solution with stir bar glass until all the salt dissolved in distilled water. Then enter this salt solution into the volumetric flask through the funnel, by way of stick rod funnel drop of fluid in the weighing bottle with stir bar glass. The liquid in the weighing bottle will flow through the stir bar glass then through the funnel and into the flask. This is done so that no liquid falls out of the flask when poured from weighing bottle. Rinse the weighing bottle with distilled water 3 times. Rinse water and insert into the volumetric flask with stirring bar and funnels.

Rinse the stir bar glass 3 times with distilled water so that the rinse water above the funnel into the volumetric flask. Rinse the funnel three times with distilled water and rinse water enter into the volumetric flask. Do not forget to rinse the funnel outer pipe that had been entered into the volumetric flask. Then rinse the pipe wall volumetrik flasc three times with distilled water. Add distilled water up to 1 cm below the line volume volumetric flask.

Dry the inside flask wall above the line volume using tissue and stir a bar glass. Take distilled water with a pasteur pipette and then push the rubber pasteur pipette in the pipeline volumetric flask, so that the droplets of distilled water in a volumetric flask hatch. Apply a drop of distilled water it until it reaches the line marked with the volume of solution basin bottom volumetric flask volume to reach the line. Take the cap volumetric flask is dried and then close the volumetric flask.

Take a volumetric flask with one hand where the index finger attached to the lid. Paste this index finger firmly to prevent leakage current in shake volumetric flask. Lift the flask with all the fingers except the index finger. Turn the flask until air bubbles there are positioned the bottom of the flask. Then flip it over again until the bubble goes to the top of the flask with an index finger remained attached to the lid. Do this 10 times. Then it's done, dissolving salt na2so4 in distilled water using a volumetric flask. The concentration of this solution can be calculated.