between the secon and third finger
never attempt to insert glass tubing that has a jagged end, all glass tubing should be fire polished before its inserted into a rubber stopper. Use water or glycerin as a lubricant at the end of the glass tubing before inserting it into the rubber stopper. ask teacher for proper lubricant. Protect hands and fingers by wearing leather gloves or placing a folded cloth between your hands and the tubing. hold it as close as possible to the part it is inserted to the rubber stopper. always point the tubing away from the palm of your hand that holds the stopper. use a twisting motion and push the tubing into the stopper. At the end of the experiment put on leather gloves or place the folded cloth between your hands and the tubing and remover the stoppers from the tubing to keep them from sticking to the glass. if it wont budge, use lubricant.
The reaction between magnesium and hydrochloric acid produces hydrogen gas, which builds up pressure inside the closed glass tube. If the pressure exceeds the strength of the rubber stopper, it will burst off to release the built-up pressure and prevent the glass tube from breaking due to the increased pressure.
The stopper of a chemical reagent container should be handled carefully for two reasons. Firstly, it may contain chemical residues which can be dangerous. Additionally, if the stopper is dirtied it may contaminate the reagent in the bottle when the stopper is put back on.
The hole in a rubber stopper is used to allow for the insertion of glass tubing or a thermometer into a container without disrupting the seal created by the stopper. This allows for measurements or additions to be made to the container while maintaining a closed system.
A rubber stopper with one hole can be used to securely hold glass tubing in place, creating a seal that prevents leaks or spills. The tubing can be inserted through the hole in the stopper, allowing for a tight fit that helps with fluid transfer or containment.
To remove a glass stopper, start by gently tapping the sides with a rubber mallet to loosen it. Then, carefully twist the stopper while pulling it upwards to remove it from the bottle. If the stopper is still stuck, try using hot water to expand the glass before attempting to remove it again.
Grease the top of the bottle!
If there is debris on the stopper it might be preventing a good seal. Try removing the rubber stopper and wipe it off to remove any debris that might be on it. Clean out the hole that the stopper goes into as well. This will help ensure a clean seal between the hole and the stopper. Put the stopper back into the hole, making sure it is a tight fit. If it still leaks you may need to buy a new stopper.
If strong bases are present in the glass-stopper bottles, they may react with the glass and etch it or change the concentration of the base. Hence plastic-stopper bottles are used for bases.
Wetting the glass tubing before inserting it into a stopper helps create a better seal by reducing the risk of air pockets. The water acts as a lubricant, making it easier to insert the glass tube into the stopper without damaging either component.
Run warm to hot water over the neck of the container. This will expand the neck and the stopper should come out.
See these two questions for the answer:[http://wiki.answers.com/Q/What_is_a_rubber_stopper_or_cork_stopper_and_how_are_they_usedWhat is a rubber stopper or cork stopper and how are they used?]and[http://wiki.answers.com/Q/What_is_a_glass_plate_and_how_is_it_usedWhat is a glass plate and how is it used?]
It can either be glass that has been ground to a powder, or two glass surfaces that have been ground to fit together precisely, such as a glass stopper in a glass chemical bottle.
Over time, the sodium hydroxide will react with the smidges of carbon dioxide in air to produce sodium carbonate, the white, crusty powder that you find around the rim of plastic capped stock bottles (for example). This powder will either prevent the ground glass stopper from sealing properly and exposing the contents to more air, or will in fact cement the ground glass stopper in the bottle, and make it impossible to remove.
never attempt to insert glass tubing that has a jagged end, all glass tubing should be fire polished before its inserted into a rubber stopper. Use water or glycerin as a lubricant at the end of the glass tubing before inserting it into the rubber stopper. ask teacher for proper lubricant. Protect hands and fingers by wearing leather gloves or placing a folded cloth between your hands and the tubing. hold it as close as possible to the part it is inserted to the rubber stopper. always point the tubing away from the palm of your hand that holds the stopper. use a twisting motion and push the tubing into the stopper. At the end of the experiment put on leather gloves or place the folded cloth between your hands and the tubing and remover the stoppers from the tubing to keep them from sticking to the glass. if it wont budge, use lubricant.
To find the density of a glass stopper, you need to measure its mass using a scale, then measure its volume by either water displacement method or calculating its dimensions if it has a regular shape. Divide the mass by the volume to calculate the density, usually in units of g/cm3 or kg/m3.
With a few exceptions (notably melting ice) objects expand when heated. If you run hot water on a bottle neck, the heat is applied directly to the bottle and only indirectly to the stopper inside the bottle, so the bottle heats first, and thereby expands sooner than the stopper does. An expanded bottle will exert less pressure on the stopper.