The chemical origin of stalactites

Chemical origin

The caverns are all distributed in the limestone mountain. The main component of limestone is calcium carbonate. When it encounters carbon dioxide-contaminated water, it will react to produce more soluble calcium bicarbonate; the water containing calcium bicarbonate will be hot or When the pressure suddenly becomes smaller, the calcium bicarbonate dissolved in the water will decompose, regenerate the calcium carbonate and release carbon dioxide. When the water at the top of the cave slowly leaks downward, the calcium bicarbonate in the water undergoes the above reaction. Some deposit on the top of the cave, some deposit on the bottom of the cave, and form stalactites at the top of the cave for a long time, and form stalagmites at the bottom. Stalactites form stone pillars when connected to stalagmites.

experiment:

Take a large cup (or test tube), dissolve a small amount of hydrated lime (ie, calcium hydroxide) in water, and let it stand still for a while. The hydrated lime that has not yet dissolved will be deposited on the bottom of the cup. At this time, the cup is divided into two layers: the upper layer is followed by water. The same clear lime water, which contains dissolved calcium hydroxide; the lower layer of lime milk, was turbid. Pour the clear lime water carefully into about 2 ml in a test tube, and then blow it through the glass tube (which can also be replaced by a plastic tube - the kind of straw used for drinking soda). Because the body exhaled gas contains carbon dioxide, lime water chemically reacts with it to produce a water-insoluble white solid limestone that becomes turbid.

Calcium Hydroxide + Carbon Dioxide → Calcium Carbonate ↓ + Water

Ca(OH)2+ CO2= CaCO3↓+H2O

If we continue to blow into the turbid lime water, it will soon become clear again. This is because carbon dioxide and calcium carbonate act to produce calcium bicarbonate that is soluble in water, so the turbid liquid will become clear as the precipitate dissolves. If this clarified liquid is heated, the calcium bicarbonate is converted into insoluble calcium carbonate, and the solution becomes turbid again.

Calcium carbonate + Carbon dioxide + Water → Calcium bicarbonate

CaCO3+CO2+H2O=Ca(HCO3)2

In nature, many limestone areas (mainly composed of limestone) are the result of the formation of strange peaks, stalactites and stalagmites.

Unlike stalactites and stalagmites, an icicle under the eaves of winter hangs from above; a bamboo shoot that springs out of the ground.

There are many cracks on the top of the cave. Water droplets are continuously leaking from every crack. Whenever the water evaporates, some limestone deposits remain. One drop, two drops, three drops... The water is constantly emerging, and it is continuously evaporating. The limestone on the top of the hole accumulates more and more, and finally a nipple is created – this is the “childhood” era of stalactites. Later, the nipple was covered with a layer of limestone outside, so that it was longer and longer. Some stalactites can reach several meters in length.

Stalagmites are close partners of stalactites. When the water droplets on the top of the cave fell, the limestone also deposited on the ground. In this way, the stalagmites grow up against stalactites. It can be said that stalactites are "Mr." and stalagmites are "postnatal". However, stalagmite chassis is large, it is relatively stable, not easy to break, so its "growth" speed is often faster than stalactite. The maximum height of stalagmites can reach 30 meters, like a "stone tower" that grows out of a flat ground.

The stalactites that are long downwards will sometimes be connected to the long stalagmites, and they will be connected together into a stone pillar. The two are rough, the middle one is thin, and the one who is not known still thinks who made it. In many limestone caves, most of the stalactites and stalagmites are not linked together; that is because the stalactites have been broken, or too much limestone has blocked the passage of the droplets, the droplets have been forced to change their path to another, and grow again. New stalactites. In this way, the stalactites and stalagmites will not "meet".

Groundwater plays a decisive role in the formation of stalactites and stalagmites. Wherever it flows, it leaves traces, either a ditch or a hole, or a stalactite, a stalagmites, or a pillar; putting it together makes it a “grove”. , "Drapery" and other wonderful scenes. This phenomenon is also often encountered in daily life: For example, the bottom of a pot used to boil water often has a layer of dirt. Take some vinegar and you will see a lot of bubbles. This is because tap water contains calcium bicarbonate, magnesium bicarbonate, etc. Some components of scale are their decomposition products when heated, such as calcium carbonate and magnesium hydroxide.

Because the temperature in nature is not as high as boiled water, the formation of stalactites and stalagmites is not so fast. It was formed through long-term sedimentation and constant changes for tens of thousands of years.

Food flavoring

Tartaric Acid, Vanillin, Menthol, Menthol Crystal, Flavoring agent, Baking powder

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