Precautions for using laboratory equipment

The air pressure inside the dropper is lower than atmospheric pressure, and the dropper is subjected to a downward force from the atmosphere. The solution is simple: heat the dropper in a water bath (not directly) to increase the vapor pressure inside the dropper and remove it.

Dropper: The dropper with a rubber tipped dropper should be suspended vertically above the instrument, and the liquid should be dropped into the instrument receiving the liquid. Do not let the dropper with the liquid touch the instrument wall; do not place the dropper flat on the experimental bench.

Fine mouthed bottle: When using the test solution from a fine mouthed bottle, remove the bottle stopper and place it upside down on a table; When pouring liquid, the label should be facing towards the palm of the hand, and the bottle mouth should be close to the test tube or instrument mouth to prevent residual liquid from flowing down and corroding the label

Measuring cylinder: When reading, the measuring cylinder& Nbsp; Keep it stable and keep your line of sight aligned with the concave liquid surface inside the measuring cylinder& Nbsp; Stay level at the lower level. The reading from above is higher, while the reading from above is lower

Measurement of liquid volume operation: First pour the liquid into the measuring cylinder until it is close to the required scale, and then use a dropper to add it to the scale line.