What is the phenomenon of camphor in clean, cold water and water containing grease?

Mothballs. One of the conditions for rotation in water or oil is that there is an external force that pushes the mothballs to move, and then they can rotate.

This can be associated with a simple chemistry experiment in high school, sodium metal.

Swimming in water is because sodium metal reacts with water to produce a large amount of hydrogen, which pushes sodium metal to move.

Mothballs do not react with water and grease to produce a large amount of gas to push mothballs, while mothballs have sublimation properties, which is a slow process, and cannot sublimate at room temperature to produce a large amount of gas to push mothballs to move.

If mothballs can be sublimated quickly, then you have to be careful, because if you buy mothballs that are mainly composed of natural ingredients, they are not toxic, but if they are composed of chemically synthetic ingredients, they are toxic and carcinogenic. At present, the mothballs sold on the market are mainly chemically synthesized, so they are very cheap, while mothballs made of natural ingredients are relatively expensive).

This assumption is that mothballs can be sublimated quickly, but whether it is natural or chemically synthesized mothballs, its sublimation effect is relatively slow, so there is no concern about the presence of a large number of carcinogenic gases in the room, of course, if you use a large number of mothballs at one time, I didn't say it).

Therefore, mothballs cannot be distinguished from whether they contain oil or not by whether they are rotated in water or oil.

Of course, I don't know the specific laboratory method for identifying whether mothballs contain oil or not.

But what is certain is that mothballs, if they have oil, are also volatile.

Volatile oil is not grease), because a few years ago when I used mothballs, I wrapped them tightly in a white paper towel and then threw them in the closet, and recently I opened these paper packets and there were no traces inside, so I can be sure that there is no oil in them.

The phenomenon of camphor being put into clean, cold water and water containing grease is that the main ingredient in mothballs is naphthol, which is highly volatile. It will dissolve, but it will not rotate.

When you put camphor in the water, the following happens:

1.Put in clean, cold water:

The camphor will sink to the bottom.

The temperature of the water does not change.

2.Put in the water containing the grease:

Camphor will float on the surface of the water.

The oil collects around the camphor and forms a small ball.

The temperature of the water does not change.

3.Put in water containing starch:

The camphor will sink to the bottom.

The starch will collect around the camphor and form a small ball.

The color of the water will darken.

4.Put in water containing soap:

Camphor will float on the surface of the water.

The soap will collect around the camphor and form a small ball.

The surface tension of the water decreases.

Use a small spoon to take a little pure camphor powder and sprinkle it on the surface of the water in the cup. If the camphor powder rotates strongly on the surface of the water, it indicates that the bottle contains oil. This is because camphor powder is insoluble in water but soluble in oil. When dissolving, the heat of dissolution is generated, which causes the water to vaporize locally, causing the camphor powder to rotate.

Good evening, there is no fixed phenomenon between the two to determine whether it is pure mothball. Mothballs are divided into two crystals, natural camphor similar to L-menthol 2-camphenone and industrially synthesized naphthol, which are not hydrophilic but lipophilic organic matter, directly put into the aqueous solution because of the high density, so it will sink to the bottom without change, and can be quickly dissolved in some fatty acid esters or organic solvents, but not necessarily rotated, and considering the cost factor, not all of the mothballs we use are single ketones and naphthols, there are also some inorganic fillers that reduce costs, such as calcium carbonate, Silica or starch, etc., are dispersed into large particles by the tableting process. In addition, most of the known fatty acid esters have very little solubility in cold water, and it is difficult to dissolve mothballs with this solid content alone, which may be caused by oil or water dissolving other hydrophilic fillers inside.

Cold water and grease alone are not effective in determining whether a white solid is a mothball.

Why don't you just try it yourself?