If water is exactly at 0 degrees, is it water or ice?

Answer 1: State of matter 1: Solid: 1: When the ice has just warmed up from below 0 to 0, 2: The ice has just begun to melt from 0, 3: The water has just completely solidified into ice, and the three conditions are that the solid state is exactly at 0 degrees.

State of matter 2: solid-liquid coexistence state: 1: when the ice is in the melting "stage", 2: when the water is in the solidification "stage", the solid-liquid coexistence state of the two conditions is exactly 0 degrees.

State of matter 3: Liquid state: 1: When the water has just cooled down from above 0 to 0, 2: the water has just begun to solidify from 0, 3: the ice has just completely melted to the water, and the liquid state of the three conditions is exactly at 0 degrees.

A2: Because you said, "If the water is exactly at 0 degrees," I think it should be in a liquid state.

Note: There are two answers, only according to your meaning.

It can be water, ice, or a mixture of ice and water!

It's not all right, because it's the triple point of water, the temperature at which water, steam, and ice can exist.

There are three possibilities: ice, water, ice-water mixture.

Under standard conditions, it is a mixture of water and ice.

Water or ice or ice-water mixture.

I remember that in the old book it was said that if the ice-water mixture was set at 0 degrees, then neither the light water nor the ice could be 0 degrees.

Hehe, not responsible.

There is ice and water, and ice and water are mixed.

The freezing point temperature of water is 0, but pure water cannot freeze at 0, and is often cooled to a supercooled state first, until the temperature decreases and a stable crystal nucleus appears, or the vibration is promoted, it will immediately convert to the ice crystal and release latent heat, and at the same time promote the temperature to rise to 0.

Ice is a crystalline formation formed by the orderly arrangement of water molecules, which are linked together by hydrogen bonds to form a very "open" (low-density) rigid structure.

The spacing between the O—O nuclei closest to the water molecule is about 109°, which is very close to the 109°28 bond angle of an ideal tetrahedron. However, the O-O spacing of each water molecule that is only adjacent and not directly bound is much larger, and the farthest one should be reached. Each water molecule can combine with 4 other water molecules to form a tetrahedral structure, so the coordination number of the water molecule is 4.

Ice is a colorless and transparent solid, a product formed by liquid solidification, condensed by a freezing environment, and liquefied and dissolved at high temperatures, which is a normal natural phenomenon that can be formed naturally or artificially.

The molecules are mainly bonded by hydrogen, but there are also van der Waals forces, and the lattice structure is generally hexagonal, which is less dense than water. However, there can also be other lattice structures at different pressures.

Ice crystals are structures in which water molecules are regularly arranged in a hexagonal shape. After heating, first of all, a water molecule detachs from the crystallization and begins to move freely, and this water molecule does not return to its original position, resulting in distortion of the crystal. Once the crystals are distorted, they will gradually expand, and eventually the entire crystals will decompose and become liquid.

The water is frozen.

The BAI temperature is not affected by the ambient temperature, but by the DAO from the atmospheric pressure. At a standard atmospheric pressure, the temperature at which water freezes is 0 degrees Celsius, and at a standard atmospheric pressure, when the temperature is below 0, the water freezes; At any pressure, the water temperature is below freezing point and can freeze, and the volume of the water increases as it freezes.

The lower the temperature, the slower the movement of water molecules, the smaller the distance between molecules, and the tighter they are arranged together, changing from liquid to solid.

When the temperature is high, the water is copied.

Molecules are in constant motion.

, water can flow. The lower the BAI temperature, the less intense the molecular DU movement. When the temperature is as low as freezing, the water molecules basically do not move, and they stop because the distance between the molecules increases a little and shows gravity, so the water does not flow, and the volume of ice is one-tenth larger than that of water.

From a macro point of view - the water freezes.

The density of the water itself, and environmental factors do not freeze.

The temperature has not dropped to 0 degrees Celsius or below, so why does the water in the cup freeze instantly?

The first thing is to see what the water is. If it is absolutely pure water, it will not freeze even if it is tens of degrees below zero.

Everyone forgets an important point. The premise for water to freeze is that it must reach the water's freezing point. And there are enough condensation nuclei in the water to freeze. There is also the fact that the water is in an unstable state.

As is the case in the Arctic, the seemingly calm surface of the water begins to condense when a solid is thrown into the water. At first, the water did not freeze because there were no condensation nuclei and the liquid was in a relatively stable state. When the stone is thrown in, it disrupts the original stable state.

Causes icing. There is also artificial rainfall and snowfall, which is actually the release of dry ice (solid carbon dioxide) into the air.

When the air is cold enough and solid particles are added, the moisture starts to condense, and when the temperature is high, it is rain, and when the temperature is low, it is snow.

0 degrees is a limit temperature, at 0 degrees, the ice-water mixture is in a special state, at this time, it does not matter who has more water and who has less, and how much proportion each has. Scientifically speaking, as long as it is at one atmospheric pressure, the temperature when the ice-water mixture is in a stable state is 0 degrees. At one atmosphere, the temperature at which water vaporizes is 100 degrees.

The difference between 0 degree ice and 0 degree water is as follows: 0 degree state (character), reheating change, and recooling change.

1. The state (character) of 0 degrees is different.

degrees of ice: stable in a solid state.

degrees of water: stable in a liquid state.

Second, the reheating changes are different.

degrees of ice: the temperature rises into water.

degrees of water: no change in temperature increase.

Third, the re-cooling changes are different.

degrees of ice: the temperature decreases without change.

degrees of water: The temperature decreases to ice.

When the ice melts, it absorbs heat but does not rise in temperature, because the temperature of the ice-water mixture is constant.

Because ice is solid, while water is liquid. The relative position between the molecules in the solid is stable, and the molecules of the liquid can flow apart, the intermolecular of solid ice is bound by hydrogen bonds to stabilize the form, and the energy consumed in the process of turning 0 degree ice into 0 degree water is used to open these hydrogen bonds and make the molecules flow away.

This part of the internal energy is converted into molecular potential energy!

The internal energy does not change, because the water at 0 degrees becomes ice at 0 degrees, the temperature does not change, and no work is done on the object.

The temperature does not change. The thermal motion of the molecules decreases because the water at 0 degrees becomes ice at 0 degrees, that is, solidification, and the solidification is exothermic, so the thermal motion of the molecules decreases.

Ice is solid and water is liquid. The amount of calories contained is different.

The state of existence is different, and the solid absorbs heat and melts.

The heat that is shouted by the quality is not the same!

First of all, it is important to note that the volume of water from 0 increases when it becomes ice of 0, which is called abnormal expansion.

The water of 0 becomes ice of 0, which is exothermic from the point of view of heat intake and intake, and it can be seen from the first law of thermodynamics that the change in internal energy is equal to the sum of the work done and the heat transferred, that is, δe=w+q

When water condenses into ice, it can be considered that there is no work done, while when exothermic q is negative, i.e., δe q," indicates that the internal energy of water decreases.

From a microscopic point of view, when water condenses into ice, the temperature does not change, that is, the average kinetic energy of the molecule does not change, and its volume increases abnormally expanding, and the actual distance between the molecules still decreases, that is, the molecular distance decreases in the range greater than r0, and the molecular potential energy decreases. Internal energy decreases.

Good luck with your progress!!

First, clarify the concept of ice-water mixture: ice-water mixture is a state in which ice and water can coexist. The temperature of the ice-water mixture is 0 at a standard air pressure of 1.

In the figure below, the ice and water in the cup are both 0.

It is necessary to clarify the conditions under which the water freezes and the conditions under which the ice melts

Water freezing conditions: the temperature drops to 0, and can continue to absorb heat at 0;

Ice melting conditions: The temperature rises to 0 and can continue to be exothermic at 0.

Explain your question:

For example, ice at -10 can rise to ice at 0, but not at 0 it will melt into water. Ice with 0 can only turn into water if it is allowed to continue to absorb heat (e.g. if it is placed above 0) in an environment above 0;

For example, water from 1 can be cooled down to 0, but it will freeze immediately if it drops to 0. Only if 0 water is allowed to continue to be exothermic (e.g. outdoors in winter) can it melt from 0 ice to 0 water.

As for your question, "Water only freezes below 0 degrees Celsius, so why is there ice at 0 degrees Celsius?" Because there is 0 degrees Celsius ice and 0 water, when 0 ice melts into 0 water, the endothermic hall is macro but the temperature remains the same, and when 0 water forms 0 ice, the heat release also remains the same temperature.

For example, if you put the ice-water mixture in the picture above outdoors in winter, the water in Juexiang will gradually freeze, but the temperature will still be 0, and the temperature will not drop until it is all frozen; When you put the ice-water mixture indoors in the summer, the ice inside will gradually melt until it is all zero water, and the temperature will rise.

The freezing point of water is 0 degrees, which means that when the temperature of the water drops to 0 degrees, it will start to freeze; You know, there is a premise here, that is, the water in question is pure water, which does not contain any impurities of the tung band, such as distilled water. For example, if the sea contains a lot of salt (calcium chloride, magnesium chloride, etc.), then the freezing point of the sea water is below 0 degrees, so in the cold winter in the north, sometimes the sea water is not frozen, but its temperature is below 0 degrees. The river water is freshwater and contains very few soluble impurities, so its freezing point is basically 0 degrees.

It should be noted here that the so-called "freezing point" refers to the freezing temperature of the water, not to the air temperature, because in order for the temperature of the water to reach 0 degrees, the temperature of the gas banquet must be below 0 degrees. This is what we experienced, when the temperature has dropped to a few degrees below zero, the river is still not frozen; Why is that? This is because although the temperature is below 0 degrees, the river water has not yet dropped to 0 degrees, and only the low temperature continues until the temperature of the river drops to 0 degrees, and the river water begins to freeze.