If we urgently need cold items, we can add table salt to ice cubes, what is the scientific basis for

The weather in summer is very hot, and many people can't do without air conditioning, but it is also a torment for people who don't have air conditioning, but some people say that salt and ice can be compared with air conditioning, so what is the principle of ice salt compared to air conditioning? What does ice with salt do?

Ice salt is equivalent to air conditioning, what is the principle of ice salt, what is the function, ice salt is as easy to use as air conditioning. When salt is poured on top of the ice, the temperature of the ice cube drops by 21, and with the help of a fan, the temperature drops by 11. It turns out that salt makes the ice melt at a lower temperature, requiring more heat to melt.

This is called unplugged cooling.

What do salt and ice do? Salt itself is not cold, but why does salt on ice lower the temperature? Strange!

Before we get started, let's think about the decomposition of objects. Whether it's a candle or an ice cube, it must absorb heat from its surroundings and then heat itself up before melting into liquid. It makes sense.

Let's formalize this question. Mix the ice with salt so that the ice always melts a little. It needs some heat around it, so the temperature will be lower.

The melted ice turns into water, and the salt dissolves in the water. The melting of salt also requires the absorption of surrounding heat. The process of melting ice and salt is repeated, and with each change, the surrounding heat is lost.

In this way, the ambient temperature can be reduced to below 0 or even to around -20. Substances like ice and salt that cool objects are called refrigerants.

In the summer, we can do this with a homemade popsicle experiment. Prepare a glass or plastic container similar to a test tube, insert a small wooden stick in the middle of the container, and fill it with sugar water. Then, break the ice into small pieces and place in a clean bucket or aluminum plate.

Pour in the crystallized salt and stir well. Put a jar of syrup in the ice cubes, turn it a few times, and you'll be making a popsicle in no time. In addition, in winter, the road surface is covered with snow and ice.

People often sprinkle some industrial salt on the pavement.

to speed up the melting of snow and ice, but thanks to this method, the temperature of the road can drop to minus 20 degrees Celsius.

Left and right, the road surface is often icy.

This is because the melting point of salt is very low, and after adding table salt, the degree of ice cubes becomes relatively thicker, and the temperature is lower, and it needs to absorb a lot of heat when melting, and when low-temperature items are urgently needed, adding table salt can directly drop the temperature of the items by about 20 degrees.

Because the addition of salt can quickly cool down, and the addition of salt will produce a chemical reaction, using a low melting point to make the ice cubes dissolve quickly and at low temperatures, according to a fusion reaction, is a physical phenomenon.

After adding salt to the ice, the ice cube can melt quickly, the composition of salt is mainly sodium chloride, and the melting point is relatively low, so the ice cube can be melted quickly.

This is because the chemical composition of salt is relatively active, and sodium ions can quickly absorb heat, reduce the freezing point of ice, and quickly dissipate heat, which is the scientific basis.

This is because the chemical composition of salt is vigorous, and sodium ions may quickly absorb heat, reduce the condensation point of ice, and dissipate heat, which is based on science.

This is because the addition of table salt to the ice mine lowers the melting point of the ice and accelerates the melting of the ice.

Because the addition of salt can be used to cool down the temperature quickly, and the addition of salt will produce a chemical reaction, which will allow the ice cubes to melt quickly and at ultra-low temperatures, following a fusion reaction, a physical phenomenon.

The freezing point decreases rapidly when salt is added to the ice, around 7. So there is ice backmelting. The temperature of the ice salt mixture is determined by the percentage of salt mixed with the ice, such as the amount of salt used in ice, the minimum temperature can reach -21.

Ice salt, refers to a mixture of ice and salt solution. A common icing salt is a mixture of ice and a sodium chloride solution. Ice salt mixtures are an effective chilling agent.

When salt is mixed with crushed ice, the salt dissolves in the ice and becomes endothermic, lowering the temperature of the ice. When ice salts are mixed together, they will greatly accelerate the melting rate of ice, and when the ice melts, it has to absorb a lot of heat; The dissolution of salt also absorbs the heat of dissolution. It can absorb a large amount of heat in a short period of time, so that the temperature of the ice-salt mixture drops rapidly, and it is much cooler than that of ice alone.

Related information

The cooling principle of the ice salt bath is related to the decrease in the freezing point of the solution. When salt and ice are evenly mixed together, the ice melts slightly into water due to the absorption of ambient heat, and the salt dissolves when it meets water, so that the surface water forms a concentrated salt solution. Because the freezing point of the concentrated salt solution is lower than that of pure water, the concentrated salt solution and ice coexist in the system.

Therefore, the temperature of the system must drop in order to maintain this coexistence (the coexistence temperature of the concentrated salt solution and ice should be lower than the freezing point of pure water). This will cause more ice to melt into water to dilute the concentrated salt solution, reducing the temperature of the system due to a large amount of endothermy during the melting process.

Adding table salt to the ice cubes can lower the melting point and make the ice cubes melt quickly. Salt melts ice. The composition of salt is sodium chloride NaCl, and the composition of snow is water.

Sodium chloride is a chemical substance that is extremely soluble in water, and sodium chloride is dissolved in water to form an aqueous solution of sodium chloride, which contains sodium ions and chloride ions.

When water is about to freeze, when there are sodium ions and potassium ions, chloride ions and sodium ions will destroy the crystalline network structure of water, so that the water cannot freeze.

Moreover, salt can lower the melting point of ice, so that it does not freeze at low temperatures.

The freezing point of brine is usually around -18 degrees, and adding a certain amount of salt to the ice can melt ice above -18 degrees. When water is converted from a solid to a liquid state, it needs to absorb heat from the surrounding environment to achieve the purpose of cooling.

Physical properties of ice:

Pure water will freeze at 0 under normal atmospheric pressure, if the water contains impurities, the pressure increases, the freezing point of water will decrease, the melting point of ice is the freezing point of water, and as the atmospheric pressure increases, the melting point of ice also increases.

The heat of melting of ice is usually taken at 335 kJ kg. The specific gravity of ice is related to its temperature, the ambient pressure at the time of ice formation, the presence or absence of air bubbles in the ice, and the purity of the water.

Generally in practice, when the temperature of ice is from 0 to -20, its average specific heat capacity is taken, while the specific heat capacity of water is only half of that of water, and the thermal conductivity of ice is related to its temperature, which increases with the decrease of temperature.

That's right.

Putting table salt on ice will make the ice melt faster by raising the temperature.

Sodium chloride can reduce its freezing point when dissolved in water, so the freezing point of crushed ice is reduced below the temperature after adding sodium chloride, which accelerates the melting of ice.

This is the reason why seawater is salt-dissolved water, and the temperature of seawater freezing in winter is lower than that of river water. The melting point of saturated salt water can drop to about -22, and the northern cities often sprinkle salt on the snow on the road when it snows heavily in winter, as long as the temperature is higher than -22 at this time, enough salt can always melt the ice and snow, which is also an application of the melting point in daily life.

That's right.

Adding salt to the ice lowers the melting point of the ice, which means it melts faster.

And the melting of ice must absorb heat from the ambient air, thus lowering the temperature.

For example, under normal circumstances, the melting point of ice is above 0, and the ambient temperature is -2, which should freeze, and after adding salt, the melting point of ice decreases, assuming that it becomes -4, so that the ambient temperature is high, and the melting point of ice will melt.

According to the physics knowledge of junior high school, melting ice will absorb heat, so it can reduce the temperature of the surrounding environment.

The freezing point decreases rapidly when salt is added to the ice, around 7. So there is ice backmelting.

Sprinkle some salt on the ice and something strange happens! What is the principle of physics?

Mix ice cubes with table salt and the ice cubes will melt on their own. Melting needs to be taken from.

The surroundings absorb heat, so the surroundings cool down. The melted ice turns into water, and the salt is dissolved in the water. The dissolution of table salt also requires the absorption of surrounding heat.

This repeats the process of melting the ice cubes and dissolving the table salt, and with each change, the heat is lost around it. In this way, the surrounding temperature can drop below 0, or even to about -20.

Adding salt to the ice lowers the melting point of the ice, and if the temperature is minus 4 degrees, it will speed up the freezing rate, and at the temperature above minus 4 degrees, the ice will melt.

The melting point is essentially the temperature at which the solid and liquid phases of the substance can coexist and are in equilibrium, taking ice melting into water as an example, the melting point of ice at an atmospheric pressure is 0, and when the temperature is 0, ice and water can coexist, if there is no heat exchange with the outside world, the state of coexistence of ice and water can remain stable for a long time

If there is a small amount of other substances dissolved in the liquid, or called impurities, even if the number is small, the melting point of the substance will change greatly, for example, there is salt dissolved in the water, the melting point will drop significantly, seawater is dissolved in salt, the temperature of seawater freezing in winter is lower than that of river water, this is the reason The melting point of saturated salt water can drop to about -220, and the northern cities often sprinkle salt on the snow on the road when it snows heavily in winter, as long as the temperature is higher than -22 at this time, enough salt can always melt the ice and snow