Lab Cylinder
What is lab cylinder?
Lab cylinder is a measuring device used in the laboratory. Cylinder in lab is mainly made of glass, while a few (especially large ones) of them are made of transparent plastic. Cylinder used in the laboratory is one of the measuring devices to measure liquid by volume. It is one of the measuring instruments for measuring a certain volume of liquid. The cylinder is generally less accurate, and cannot be used as a reactor. It should never be heated, and should not be used for preparing solutions or diluting solutions.
Laboratory measuring cylinders are generally long, vertical cylinders with a spout on one side of the upper rim for easy pouring. The lower part has wide feet to maintain stability. The cylinder wall is engraved with a volume measurement range for the user to read the volume. The maximum measured volume ranges from a few milliliters to several liters. The cylinder wall is stamped with a scale from the bottom up. When observing the reading, the experimenter should be aware that the line of sight needs to be level with the liquid’s lowest part of the concave surface (or the highest part of the convex surface).
Lab cylinder specifications
Lab cylinders are generally available in 5mL, 10mL, 25mL, 50mL, 100mL, 250mL, 500mL, 1000mL and other specifications.
Lab cylinder accuracy
The lab cylinder is a coarse measuring instrument.
Regarding its accuracy, if the minimum scale of the measuring cylinder with a range of 5mL is 0.1mL, its accuracy is 0.1mL; if the minimum scale of the measuring cylinder with a range of 10mL is 0.2mL, its accuracy is 0.2mL; the minimum scale of the measuring cylinder with a range of 50mL is 1mL, its accuracy is 1mL, and so on.
A common accurate lab cylinder can only be recorded to one valid value after the decimal point, such as 7.2mL.
Function of lab cylinder
Cylinder in lab
A. General uses of lab cylinder
In addition to the lab cylinder, other containers that can be used in the laboratory to measure the volume of liquids are graduated pipettes, pipettes, and droppers. The first two are more accurate than the measuring cylinder, but a pipette can only measure a fixed amount of solution at a time. Graduated pipettes can measure the required graduated amount, while droppers are more cumbersome to use and relatively less accurate. The dropper is generally used for rough pipetting, such as color development, buffer, etc.
B. Special uses of lab cylinder
a. Measure the volume of solids. In the first step, take a certain amount of water in the lab cylinder and record the initial reading. In the second step, add the solid to the lab glass cylinder and record the final reading. Finally, the volume difference is the volume of the solid.
b. Measure the volume of the gas. The volume of the liquid entering the measuring cylinder is approximated as the volume of the gas produced.
Operation with lab cylinder
Cylinder used in laboratory
How to fill a lab cylinder with liquid?
When filling a lab cylinder with liquid, hold the cylinder with your left hand so that it is slightly tilted, and hold the reagent bottle with your right hand so that the mouth of the bottle is next to the mouth of the cylinder and the liquid flows in slowly. (The reading of the measuring cylinder is rough).
Which side of the cylinder should the scale be?
There is no “0” scale in a lab cylinder, and the general starting scale is 1/10 of the total volume. In many experimental operations, the scale face of the measuring cylinder is back to people, which is very inconvenient, because the line of sight is through the two layers of glass and liquid. If the liquid is cloudy, it is more difficult to see the scale, and the scale numbers are not smooth to the eye, so it is better to face the scale.
How to read the required volume of the liquid?
Hold the lab cylinder in your hand so that it is naturally vertical and your line of sight is level with the lowest point of the concave surface of the liquid in the measuring cylinder, then read the volume of the liquid taken. Otherwise, the reading will be high or low.
Can a lab cylinder be heated or measure superheated liquids?
The scale on the face of the lab cylinder is the number of volumes at a temperature of 20℃. When the temperature rises, the cylinder expands thermally and the volume increases. It follows that a measuring cylinder cannot be heated, neither can it be used to measure overheated liquids, nor can it be used to perform chemical reactions or prepare solutions in a measuring cylinder.
Should lab cylinder be rinsed with water after use?
It depends on the situation.
If the purpose is simply to make the measurement accurate, there is no need to rinse the cylinder with water, as the cylinder is manufactured with residual liquid in mind. On the contrary, if you rinse it, the volume taken will be larger. If you want to use the same cylinder to measure another liquid, you must rinse it with water to prevent contamination by impurities.
Note
Lab cylinder can only be used when the accuracy requirements are not very strict, usually applied to qualitative analysis, generally not for quantitative analysis, because the error of the cylinder is large.
When reading, does the measuring cylinder need to be looked up or down?
When looking at the volume of the lab cylinder, you are looking at the center of the water surface.
When looking down, the line of sight is slanted downward and the intersection of the line of sight and the wall of the lab cylinder is above the surface of the water, so the reading is higher and the actual value of the solution is lower.
When looking up, the line of sight is slanted upward, and the intersection of the line of sight and the wall of the lab cylinder is below the surface of the water, so the readings are low, and the actual measurement of the solution value is high.
Why can’t a measuring cylinder be heated directly, chemical reactions be performed in a measuring cylinder, or solutions be prepared in a measuring cylinder?
Reasons why a measuring cylinder cannot be heated directly, chemical reactions cannot be performed in a measuring cylinder, and solutions cannot be prepared in a measuring cylinder
a. The volume of the lab cylinder is too small for the reaction.
b. You cannot dilute or prepare solutions in the lab cylinder, and you cannot heat the cylinder, so it is not easy to prepare solutions.
c. Chemical reactions cannot be carried out in a lab cylinder to avoid harming the cylinder and sometimes even danger.
d. The reaction may be exothermic.
Note
When measuring liquids, choose the right size of the lab cylinder according to the volume to be measured (otherwise it will cause a large error). When reading, the cylinder in lab should be placed vertically and smoothly on the table, and the scale of the cylinder chemistry lab should be kept at the same level as the lowest point of the concave liquid surface inside the cylinder. Generally, the thinner the diameter of the measuring cylinder, the better, because it is more accurate. The area of the circle can only be calculated roughly, so the larger the diameter, the greater the error.
What is the scale of the lab cylinder starting from?
The minimum scale is usually one-tenth of the maximum scale. For example, if the maximum scale is 1mL for a 10mL measuring cylinder, the minimum scale should be 50mL for a 500mL cylinder.
Use of lab cylinder
a. You must place the lab cylinder smoothly when it is in use. Then you should face the scale and fill the measuring cylinder with liquid. When the liquid level is close to the specified volume, you should switch to using a rubber-tipped dropper to add liquid drop by drop until the lowest point of the concave liquid level. At this point, the lowest point of the concave liquid surface, the scale line, and your eyes are required to maintain a consistent horizontal line.
b. Before reading. When filling the lab cylinder with liquid, it is generally recommended not to take a reading immediately. Let the liquid attached to the inner wall of the cylinder flow down before reading, otherwise, the readout value will be small.
c. When reading the numbers. Looking flat is the correct way to read while looking up and looking down are both wrong ways to read. If you look up (from the bottom to the top) read out the value will be less than the actual value, and look down (from the top to the bottom), read out the value will be greater than the actual value.
d. After reading. Immediately after the reading, you should pour the liquid into the designated container. After pouring, gently scrape the small spout of the lab cylinder on the wall of the container, and finally, rinse the cylinder with water for the next use.
How to buy lab cylinder?
If you are interested in our Lab Cylinder or have any questions, please write an e-mail to info@antiteck.com, we will reply to you as soon as possible.