Principle of snowmelt agent

To put it simply, the principle of the snowmelt agent is to take advantage of the fact that the freezing point of salt water is lower than the freezing point of water. In fact, the snow is melting and solidifying continuously, but the two are at the same speed, in a state of equilibrium, after being sprinkled with salt. The water around the snow becomes salt water, but fails to solidify, so the snow will melt and become less and less.

Further, dissolution is a physical and chemical process. When the solute is dissolved in a solvent to form a solution, the properties of the solution are different from those of the original solute and solvent. Some properties of the solution are related to the nature of the solute, such as color, conductivity, etc. However, the other properties of the solution, such as the decrease of vapor pressure, the increase of boiling point, the decrease of freezing point and the osmotic pressure, are related only to the concentration of solute particles in the solution, but not to the nature of the solute. Because of the change of this kind of properties, it is only applicable to dilute solution, which is called the dependent property of dilute solution. For example, the freezing point of the solution of frozen salt decreases with the increase of salt concentration, and the freezing point decreases to the crystal point of ice salt and dilute solution. The freezing point and boiling point are numerically dependent, which is related to the amount of solute in every 1000 g solvent. For every 1 mol/1000 g of water, the freezing point decreases by about 1. 86 ℃. If 1000 g of water dissolved in 58. 5 g of NaCl, that is, about 1 mola. The freezing point of the brine is about -3.72 ℃, so that the freezing point can be roughly deduced from the concentration of the brine.