What is the graduated cylinder used for How to use the graduated cylinder

(1) When using the graduated cylinder, it must be placed smoothly.

2) When reading, the line of sight should be kept level with the lowest part of the concave liquid level in the graduated cylinder, and the reading should not be looked up or down.

3) When measuring the liquid quantitatively, first pour the liquid into the graduated cylinder, and when there is 1ml and 2ml away from the scale, use the rubber head dropper to add until the engraving line.

(4) When measuring a certain amount of liquid, keep the viewpoint, engrave the line, and on a horizontal line at the lowest part of the concave liquid level. For the actual liquid reading, keep the viewpoint, the lowest part of the concave liquid level, the engraved line is on a horizontal line, if you look up, the reading is small, and the bottom view is large.

5) The graduated cylinder cannot be used to heat or measure the hot liquid, cannot be used as a reaction vessel, cannot dissolve or dilute the solution in the graduated cylinder, etc.

6) The specification of the graduated cylinder is equal to or slightly greater than the volume of the liquid measured, and cannot be less than the volume of the liquid.

The scale unit of the graduated cylinder is ml, with 10 ml, 25ml, 50 ml, 100 ml, 250 ml, 500 ml, 1000 ml, etc., the outer wall scale is in ml units, on the graduated cylinder, there are 5 small grids between 10ml, and a small grid represents 2ml, that is, the index value of the graduated cylinder is 2ml.

The larger the graduated cylinder, the thicker the diameter, the smaller its accuracy, and the greater the reading error caused by the deviation of the line of sight Therefore, according to the volume of the solution taken, the smallest size of the graduated cylinder that can be measured at one time should be selected as far as possible in the experiment.

How to use the graduated cylinder

When filling the liquid into the graduated cylinder, hold the graduated cylinder with your left hand so that the graduated cylinder is slightly tilted, and hold the reagent bottle in your right hand so that the mouth of the bottle is close to the mouth of the graduated cylinder, so that the liquid flows in slowly. (Graduated cylinders are coarse).

There is no "0" scale for graduated cylinders, and the general starting scale is 1 10 of the total volume. The experimental drawings in many chemistry books, the scale faces of the graduated cylinders are carried on people's backs, which is very inconvenient. Because the line of sight has to pass through two layers of glass and the liquid, if the liquid is cloudy, it is even more difficult to see the scale, and the scale number is not pleasing to the eye.

So the scale is good for talents.

1. General use.

There are also graduated pipettes and pipettes used to measure the volume of liquids.

and droppers, the first two of which are more accurate than graduated cylinders. However, a pipette can only measure a fixed amount of solution at a time, and a graduated pipette can measure the required scale, while a dropper is more cumbersome to use and relatively accurate.

Poor, generally used for rough pipetting, such as chromogen, buffer.

Wait. 2. Special purposes.

1. Measure the volume of the solid: first take a certain amount of water in the graduated cylinder, record the initial reading, then add the solid substance to the graduated cylinder, and then record the reading at the end of the closed staring, and the volume difference is the volume of the solid.

2. Measure the volume of gas: the volume of the liquid entering the graduated cylinder is approximate to the volume of the gas generated.

Extended Information: A graduated cylinder is a type of measuring instrument used in the laboratory, mainly made of glass, and a few (especially large ones) are made of clear plastic. The purpose is to take a liquid by volume.

One of the measuring instruments used to measure a certain volume of liquid. Graduated cylinders are generally less accurate. It cannot be used as a reactor, it must not be heated, and it cannot be used to prepare solutions or dilute solutions.

It is a vertical and cylindrical shape, and there is a mouth on one side of the upper edge for easy pouring. The lower part has wide feet for stability. The volume range is engraved on the wall of the cylinder for the user to read the volume.

The maximum measured volume ranges from a few milliliters to several liters. The walls of the cylinder are marked with scales from the bottom up. When observing the readings, the experimenter should be aware that the line of sight needs to be at the lowest point of the concave surface of the liquid (or the highest part of the convex surface) of the liquid.

A graduated cylinder, measuring cylinder or graduated glass is a glass instrument used to measure liquids. A graduated cylinder is an instrument that measures the volume of a liquid. The specifications are expressed in terms of the maximum capacity (ml) of the energy capacity, and the commonly used ones are 10 ml, 25 ml, 50 ml, 100 ml, 250 ml, 500 ml, 1000 ml, etc.

The outer wall scale is measured in ml, with a 10 ml graduated cylinder representing ml per compartment and a 50 mL measuring cylinder representing 1 mL per compartment. The larger the visible graduated cylinder, the thicker the diameter, the smaller the accuracy, and the greater the reading error caused by the deviation of the line of sight. Therefore, according to the volume of the solution taken, try to choose the smallest specification of the graduated cylinder that can be measured at one time.

Fractional measurements can also cause errors. If you take 70ml of liquid, you should use a 100ml measuring cylinder.

Graduated cylinder: Take a rough measure of the volume of liquid. Note:

1. There is no zero scale mark in the graduated cylinder, which should be paid attention to when using; 2. The graduated cylinder is a coarse instrument, accurate to milliliters, and the next digit should not be estimated when the degree; 3. The graduated cylinder should not be used as a container for chemical reaction or dissolution, because the heat released or absorbed in this process will cause the deformation of the graduated cylinder, thereby affecting its accuracy; 4. For the liquid to be measured, the volume should be estimated first, and the graduated cylinder close to and larger than its volume should be selected for measurement.

The correct way to read the graduated cylinder is: eye, scale mark, lowest part of the concave surface, and the three points are kept on the same horizontal line.

First, the process of measuring cylinder reading.

Before reading, when the liquid is injected into the graduated cylinder, generally do not read immediately, let the liquid attached to the inner wall of the graduated cylinder flow down and then read, otherwise the reading value will be small; In addition, when reading, head-up is the correct way to read.

2. Precautions for using graduated cylinders.

1. It cannot be used as a reaction vessel.

2. It cannot be heated. Graduated cylinders are glassware, and heating will deform them, which will affect their accuracy, especially repeated long-term heating and high-temperature heating.

3. It cannot dilute concentrated acid, concentrated alkali, especially corrosive liquids. Although glass is an inert material, it is not without a little activity, and certain strong acids and alkalis, especially strong alkalis, can still corrode it, so long-term storage or long-term use of graduated cylinders is also inaccurate.

4. Cannot store medicines. A graduated cylinder is a measuring device, not a container, and is not suitable for storing liquids.

5. The hot solution cannot be measured. If you measure a liquid that is too hot or too cold, it is not accurate.

6. Can not be cleaned with decontamination powder to avoid scratching the scale, the measuring cylinder is not allowed to be brushed, because brushing will wear the inner wall of the graduated cylinder, resulting in changes in the content volume of the graduated cylinder, and the code will affect the accuracy of the graduated cylinder.

7. Wash with a bend. Sometimes, after we finish pouring, we find that there are a lot of hanging walls in the graduated cylinder, and we feel that the amount poured is not enough, so we are using solvents or other means to moisten repeatedly. In fact, this is also wrong, because the design of the graduated cylinder was designed with the wall of the graduated cylinder in mind, and this part of the volume is taken into account, and the volume poured out is the volume we need.