Why does liquid water solidify when heated?

Ice is melted into water, some of the hydrogen bonds in the associated water molecules are broken, and the crystals of the ice disappear. The water of 0 is denser than the ice of 0, the number of individual water molecules in the associated water molecule is reduced, the spacing of the molecules becomes smaller, and the voids are reduced, so the water of 0 is denser than the ice of 0. Irradiating 0 water with Roentgen rays found that only 15 hydrogen bonds were broken, and about 85 tiny Xiaoice crystals (i.e. large associative water molecules) remained in the water.

If the water of 0 is continued to be heated, as the water temperature increases, the large associated water molecules gradually disintegrate and become three-molecule associated water molecules, bimolecular associated water molecules, or single water molecules. These small associative water molecules, or individual water molecules, are less affected by the hydrogen chain and can be arranged and moved arbitrarily, and individual water molecules can also be "embedded" in the middle of large associative water molecules.

In the process of increasing water temperature, on the one hand, the proportion of associated water molecules and single water molecules with small association number in water gradually increases, the accumulation degree (or density) of water molecules gradually increases, and the density of water also increases. On the other hand, in this process, as the temperature increases, the speed of water molecules increases, so that the average distance of the molecules increases, and the density decreases.

When considering the law of water density with temperature, the influence of two factors should be comprehensively considered. In the process of rising water temperature from 0 to 4, the effect of increasing the density of water caused by the breaking of the hydrogen bond of the associated water molecule is greater than the decrease of water density caused by the acceleration of the thermal movement of the molecule, so in this process, the density of water increases with the increase of temperature, which is abnormal expansion.

It's not solidification, it's the precipitation of the substance in the water.

Because liquid water evaporates slowly during heating.

Because it will gradually evaporate, and then it will solidify.

Heating only softens the water and does not change its chemical composition.

It may be that the dissolved calcium in the water has been expelled.

Because the special ingredients in it are starting to change.

Because the water can be evaporated.

Because the chemical composition of the water has not changed in any way.

There are some material changes in the water.

Isn't liquid water supposed to evaporate when heated?

Water freezes and turns from a liquid into a solid, a process called solidification. The change of matter from a liquid state to a solid state is called solidification. Exothermic during solidification.

Like melting, crystals have a certain solidification temperature, which is called the freezing point.

The heat dissipation temperature of the crystal decreases, and it begins to solidify when it reaches the freezing point, and the temperature remains unchanged during solidification. After the crystals have completely solidified into a solid, the temperature continues to drop. During the solidification process, the crystal is in a state of coexistence of solid and liquid.

Amorphous do not have a certain solidification temperature. The solidification process of amorphous crystals is similar to that of crystals, except that the temperature continues to rise during solidification, which requires continuous heat absorption and release.

Water becomes ice called solidification, water water vapor (evaporation) ice water vapor (sublimation) ice water (melting) water ice (solidification) water vapor water (condensation) water vapor

As the temperature rises, water can be heated or turned into water vapor that flies into the air, and the water vapor in the air can turn into fog, dewdrops, rain, snow, hail, etc. When the temperature is too low, the water can freeze directly. Water can also be turned into hydrogen and oxygen, among other things.

Water (chemical formula: Ho) is an inorganic substance composed of hydrogen and oxygen and is non-toxic. The colorless and odorless transparent liquid at room temperature and pressure is known as the source of human life.

Water is needed for various physiological activities of human beings, for example, water can dissolve various nutrients, fats, and proteins (protein foods) to be absorbed in a colloidal state suspended in water; Water flows continuously between blood vessels and cells, transporting oxygen and nutrients to tissue cells, and then excreting metabolic waste products from the body.

In short, water is indispensable for human metabolism and physiological activity. Water plays a role in thermoregulation When a person breathes and sweats, some water is excreted from the body.

For example, during the hot season, the ambient temperature is usually higher than the body temperature, so people rely on sweating to evaporate the water and take away some heat to lower the body temperature and prevent heat stroke. However, when the weather is cold, the body temperature does not fluctuate significantly due to the low outside temperature due to the great potential of water to store heat.

Water, steam, clouds, rain, water.

The liquid is illuminated, evaporates, becomes water vapor and rises, reaching a certain height due to the drop in temperature, it becomes ice crystal particles or small water droplets, condensing into clouds. When the clouds evolve to a point where there is too much liquid in them to bear the weight, they will fall as rain.

Categories: Education, Science, >> Science & Technology.

Problem description: It is best to have the perspective of the internal energy of the molecular branch nucleus from multiple angles.

Analysis: The melting process is the melting process, which is an endothermic process.

The phase transformation process of a substance, such as a nucleus, from a solid phase to a liquid phase. Under a certain pressure, the solid (crystal) must be heated to a certain temperature (melting point) before it can be melted, and the temperature does not change during the melting process, and heat is absorbed from the outside. The heat absorbed by the melting of a unit mass crystal into a liquid is called the latent heat of melting, or heat of fusion for short.

The melting of a crystal is the process in which the lattice particles are excavated from a regular arrangement to a disordered state, and the heat of fusion is the energy required to destroy the lattice structure, which can be used to measure the binding energy of the crystal.

The melting point of different crystals is different, and the melting point of the same crystal is also related to the pressure during melting. The curve that represents the relationship between melting point and pressure on the P-T diagram is called the melting curve, which is the dividing line between the solid and liquid phases, and the points on the curve represent the various states of the coexistence of the solid and liquid phases in equilibrium. Most crystals expand in volume when melted, and the melting point decreases as the pressure increases.

The melting point is also closely related to the purity of the crystal, and a small amount of impurities can often significantly reduce its melting point, and the melting point of the alloy is often lower than the lowest melting point of each metal component in it.

The melting of amorphous solids such as glass, paraffin, resin, asphalt, plastics, etc., does not take place at a specific temperature and has no melting point to speak of. They gradually soften as the temperature rises during the melting process and eventually turn into a liquid.

Solidification is the opposite...

Liquid water begins to solidify into ice when it reaches 0, and solid ice can turn back into liquid water at 0. Water is a colorless and odorless transparent liquid at room temperature and pressure. In nature, pure water is very rare, water is usually a solution of acids, alkalis, salts and other substances, and it is customary to still call this aqueous solution water.

water

Water, with the chemical formula HO, is an inorganic substance composed of two elements, hydrogen and oxygen, which is non-toxic and drinkable. It is a colorless and odorless transparent liquid at room temperature and pressure, and is known as the source of human life. Water is one of the most common substances on Earth.

72% of the Earth's surface is covered by water. It is an important resource for the survival of all life, including inorganic chemistry and human beings, and it is also the most important component of living organisms.

Pure water is a very weak electrolyte with very weak electrical conductivity. Water in daily life has more anions and cations due to the dissolution of other electrolytes, so it has more obvious conductivity.

1. Colloids, heating can make colloids solidify and precipitate, such as egg whites and silicone gels, which are also heated and coagulated.

2. Thermosetting resin, a kind of plastic, does not flow in the case of no heating, once heated, it will solidify and become a hard plastic, but it is different from common plastic plastics, because this kind of hard plastic, once heated once, reheated, it will only get harder and harder, and will not become soft.

The crystal molecules are arranged in a regular manner, and the molecules can only vibrate constantly near the equilibrium position, so it has kinetic energy, which in turn has thermal energy due to the interaction between the molecules that are regularly arranged. Before the crystal begins to melt, the energy obtained by endothermic object is mainly converted into the kinetic energy of molecules, so the temperature of the crystal continues to rise When it reaches a certain temperature, that is, the melting point, the energy obtained by endothermy is mainly used to overcome the gravitational force between molecules to do work, increase the distance between molecules, and make the molecules move away from the original equilibrium position, so that the regular arrangement of molecules is destroyed, and the crystal changes from solid to liquid

On the contrary, in the process of solidification, the intermolecular distance of the liquid shrinks, and the molecules change from chaotic to regular arrangement, and its potential energy decreases, but the kinetic energy does not change, so the liquid is exothermic but the temperature remains unchanged during the solidification process

In the process of melting and solidifying the crystal, the temperature does not change, but the internal energy changes, and the internal energy increases when it is endothermic and decreases when it is exothermic

The molecular structure of amorphous is similar to that of liquid, it is chaotic, and the energy obtained by endothermy is mainly converted into molecular kinetic energy, so the temperature rises, and there is no certain melting point in the process of changing from solid state to liquid state When it is exothermic, the molecular kinetic energy decreases, the temperature decreases, and there is no certain freezing point from liquid state to solid state.