Does salt water boil faster? Why salt water boils faster: physical laws of boiling

Why is it easier to swim in salt water than in fresh water?

It is easier to swim in salt water than in fresh water because salt makes the water heavier: if you take two tanks of the same capacity, one containing salt water and the other containing fresh water, the tank with salt water will weigh a little more. With what higher density(weight) of water, the easier it is to swim in it.

An object can float in a liquid if its weight is equal to the weight of the water it displaces or pushes out (the water is displaced to make room for the object). You can look at it from the other side: when you sit in the bathtub, you see that the water level in it is rising. If you knock down the water that your body has displaced, the weight of that water will be equal to the weight of your body. If the water has a higher density, like salt water, then your body will displace less of it (i.e., less water will be needed to equal your body weight), and you will emerge higher than if you had surfaced in fresh water.

The first glass contains regular fresh water, the second glass contains salt water,
in the third - very salty.

Which retains heat better: fresh or salt water?

Two vessels were filled with fresh water. They were heated for about 10 minutes. Then, 2 tablespoons of salt were added to one of the containers and labeled “salt water.” On the first try, there was no noticeable difference; the temperature was 120 degrees. On the second try, we added 2 more tablespoons of salt and the difference became noticeable. Salt water cooled much faster than normal water tap water. As part of the experiment, the amount of salt in the water was monitored. When the water temperature reached 90 degrees, data collection began. The same thermometers were used throughout the experiment.

Why is the water in the ocean salty?

Salt from the Earth's surface constantly dissolves and ends up in the ocean.
If all the oceans were dried up, the remaining salt could be used to build a wall 230 km high and almost 2 km thick. Such a wall could go around the entire equator. Earth. Or another comparison. The salt of all the dried up oceans is 15 times larger in volume than the entire European continent!
Regular salt is obtained from sea water, salt springs, or when developing deposits rock salt. Sea water contains 3-3.5% salt. Inland seas, such as the Mediterranean Sea, the Red Sea, contain more salt than high seas. The Dead Sea, occupying only 728 square meters. km., contains approximately 10,523,000,000 tons of salt.
On average, a liter of sea water contains about 30 g of salt. Rock salt deposits in various parts the lands were formed many millions of years ago as a result of the evaporation of sea water. To form rock salt, nine-tenths of the volume of sea water must evaporate; It is believed that inland seas were located on the site of modern deposits of this salt. They evaporated faster than new ones arrived. sea ​​water- so rock salt deposits appeared.
Basic quantity table salt extracted from rock salt. Usually, mines are laid to salt deposits. Clean water is pumped through the pipes, which dissolves the salt. Through the second pipe this solution rises to the surface.

Why does fresh water boil faster than salt water?

Salt water boils at more than high temperature than fresh water, respectively, under the same heating conditions, fresh water will boil faster, salt water will boil later. There is a whole physico-chemical theory why this is the case, but “on the fingers” it can be explained as follows. Water molecules bind to salt ions - the process of hydration occurs. The bond between water molecules is weaker than the bond formed by hydration. Therefore the molecule fresh water easier (at a lower temperature) to break away from its “surroundings” - i.e. roughly speaking, it evaporates. And in order for a water molecule with dissolved salt to “escape from the embrace” of salt and other water molecules, more energy is required, i.e. high temperature.

Boiling is the process of transition of a substance from liquid to gaseous state(vaporization in liquid). Boiling is not evaporation: it differs in what can happen only at a certain pressure and temperature.

Boiling – heating water to boiling point.

Boiling of water is a complex process that occurs in four stages. Consider the example of boiling water in an open glass vessel.

At the first stage When water boils, small air bubbles appear at the bottom of the vessel, which can also be seen on the surface of the water on the sides.

These bubbles are formed as a result of the expansion of small air bubbles that are found in small cracks in the vessel.

At the second stage an increase in the volume of bubbles is observed: more and more air bubbles rush to the surface. There is saturated steam inside the bubbles.

As the temperature rises, the pressure of the saturated bubbles increases, causing them to increase in size. As a result, the Archimedean force acting on the bubbles increases.

It is thanks to this force that the bubbles tend to the surface of the water. If the top layer of water has not had time to warm up up to 100 degrees C(and this is the boiling point clean water without impurities), the bubbles sink down into hotter layers, after which they rush back to the surface again.

Due to the fact that the bubbles are constantly decreasing and increasing in size, bubbles appear inside the vessel. sound waves, which create the noise characteristic of boiling.

At the third stage rises to the surface of the water great amount bubbles, which initially causes a slight cloudiness of the water, which then “turns pale.” This process does not last long and is called “white boiling”.

Finally, at the fourth stage After boiling, the water begins to boil intensely, large bursting bubbles and splashes appear (as a rule, splashes mean that the water has boiled strongly).

Water vapor begins to form from the water, and the water makes specific sounds.

Why do the walls “bloom” and the windows “cry”? Very often, builders are to blame for this because they incorrectly calculated the dew point. Read the article to find out how important this is physical phenomenon, and how can you still get rid of excess dampness in the house?

What benefits can melt water bring to those who want to lose weight? You will learn about this; it turns out that you can lose weight without much effort!

Steam temperature when water boils ^

Steam is the gaseous state of water. When steam enters the air, it, like other gases, exerts a certain pressure on it.

During the process of steam formation, the temperature of the steam and water will remain constant until all the water has evaporated. This phenomenon is explained by the fact that all the energy (temperature) is directed towards turning water into steam.

IN in this case dry saturated steam is formed. There are no highly dispersed particles of the liquid phase in such vapor. Also steam can be saturated wet and overheated.

Saturated steam containing suspended highly dispersed particles of the liquid phase, which are evenly distributed throughout the entire mass of steam, is called wet saturated steam .

At the beginning of boiling water, just such steam is formed, which then turns into dry saturated steam. Steam, the temperature of which is higher than the temperature of boiling water, or rather superheated steam, can only be obtained using special equipment. In this case, such steam will be close in its characteristics to gas.

Boiling point of salt water^

The boiling point of salt water is higher than the boiling point of fresh water. Consequently salt water boils later than fresh water. Salt water contains Na+ and Cl- ions, which occupy a certain area between the water molecules.

In salt water, water molecules attach to salt ions in a process called hydration. The connection between water molecules is significantly weaker connection formed during the hydration process.

Therefore, when fresh water molecules boil, vaporization occurs faster.

Boiling water with dissolved salt will require more energy, which in this case is temperature.

As the temperature increases, the molecules in salt water move faster, but there are fewer of them, causing them to collide less frequently. As a result, less steam is produced, the pressure of which is lower than that of fresh water steam.

In order for the pressure in salt water to become higher than atmospheric pressure and the boiling process to begin, a higher temperature is required. When adding 60 grams of salt to 1 liter of water, the boiling point will increase by 10 C.

I wrote in Russian that boiling water LIE

No, this is not Russian.

Quote: Vladimir S

Just don’t eat all the boiling water in surprise.

Very simple and memorable advice on how to forever stop confusing these verbs with similar semantic loads.

So, the verb “to lie” without a prefix is ​​not used. Therefore, if you desperately need to use it, then feel free to add any prefix that makes sense and go ahead: put, lay out, lay out, rearrange, fold, etc.

But the verb “put,” on the contrary, for some reason does not like prefixes. But he loves it when the emphasis is placed correctly: klaU, klaDI, klaLA (incorrectly - klaLA), the participle klAvshiy, the gerund kladYA.

Only a chemist can benefit from Google Chemistry

It depends on the individual. You can look at a book and see nothing.

The scale in the kettle is salt, albeit sparingly soluble, i.e. theoretically, water in a kettle with scale will boil at t greater than 100

And it turned out that the sea is salty, because salty herrings swim in it

Theoretically, in terms of b.b. and b.m. magnitudes, salted herrings thrown into a fresh sea can make it salty. Again, we need to see how many herrings there will be.

Without increasing the pressure above one hundred degrees, even Einstein will not heat it up.

He can’t do this in a laboratory, but an ordinary citizen, in an ordinary kitchen, in an ordinary microwave, can do it easily.
And further

And in general, the North was not interested in some kind of boiling centers, but why bonds in hydrated ions

This is definitely not what interests him.

Quote: North

if you salt water, it will boil faster

As we have seen many times above, water without salt can easily be overheated, but it will take longer. If you salt it in advance, it will take less time, the water will not be overheated, it will boil at 100°C.

And despite the fact that with increasing salt concentration, water begins to boil at a higher temperature, but theoretically it turns out that if you add salt, it will boil earlier. But the examples show that not only theoretically, but also quite practically. And why did he say theoretically - because it is still desirable, if not necessary, to take purified or even distilled water, and the dishes should be clean and smooth.

You don't always see this in a regular kitchen. Usually we boil whatever water we have, often even from the tap, in an ordinary scratched container, and add salt not for tea, but for soup, that is, along with the salt, there are other ingredients there. There can be no talk of any overheating here. But the person who asked the question did not provide details.

Boilers are neutral and do not affect the boiling point.

the boiling pots are placed in the water even before heating begins

Boilers are a developed, rough, spongy, porous surface. We will consider in this capacity the surface roughness of the glass bulb.

1. Flask with fresh bidistillate. Everything is clean everywhere.
2. A flask with a roughness invisible to the eye.
3. A flask with a bottom scratched from the inside with sandpaper.

In all three, the boiling point will be different. Boiling, that's exactly what I was talking about North. Although the temperature boiling in all three cases, of course, will be the same.

By the way, food should be salted after it is ready. I almost I don't add salt. Not after reading Bragg, but since childhood, such are taste preferences.