2023年2月27日 · Freezing point depression is a colligative property observed in solutions that results from the introduction of solute molecules to a solvent. The freezing points of solutions are all lower than that of the pure solvent and is directly proportional to the molality of the solute.

Tf=Kfm(1) 式中， Tf为凝固点降低值，m为溶液质量摩尔浓度，Kf为凝固点降低常数，它与溶液的特性有关。 下表给出了部分溶剂的凝固点降低常数值。

若已知某溶剂的凝固点降低常数Kf值，通过实验测定此溶液的凝固点降低值T，即可计算溶质的分子量MB。 通常测凝固点的方法是将溶液逐渐冷却，但冷却到凝固点，并不析出晶体，往往成为过冷溶液。 然后由于搅拌或加入晶种促使溶剂结晶，由结晶放出的凝固热，使体系温度回升，当放热与散热达到平衡时，温度不再改变。 此固液两相共存的平衡温度即为溶液的凝固点。 但过冷太厉害或寒剂温度过低，则凝固热抵偿不了散热，此时温度不能回升到凝固点，在温度低于凝固点 …

可用公式表示： Tf=Kfm。 式中 Tf是凝固点降低的度数，Kf是溶剂的凝固点降低常数，m是溶液的质量摩尔浓度。 【渗透压】当溶液与纯溶剂（或两种浓度不同的溶液)用半透膜隔开时，溶剂分子能通过半透膜从纯溶剂一边进入溶液，或从稀溶液一边进入浓溶液，这种 ...

Freezing point depression refers to the lowering of the freezing point of solvents upon the addition of solutes. It is a colligative property of solutions that is generally proportional to the molality of the added solute. The depression in the freezing point of a solution can be described by the following formula. ΔTf = i×Kf×m. Where.

2014年5月2日 · You will need to use the equation: ΔTf = Kf mi ΔTf = how much the freezing point is lowered Kf = freezing point depression constant of water (-1.86°C/m) m = the molality of the solution (mol solute/kg solvent) i = the number of dissolved particles the solute produces The i for any molecular compound is 1 For ionic compounds, you'll need to know ...

Kf is called the molal freezing point depression constant and represents how many degrees the freezing point of the solvent will change when 1.00 mole of a nonvolatile nonionizing (nondissociating) solute dissolves in one kilogram of solvent. The table below gives values of Kf for various solvents.

Using Omni's freezing point depression calculator, you can estimate the change in the freezing point temperature of a solution compared to the pure solvent. Ever wondered why we use common salt to de-ice roadways and sidewalks during winter? How does adding a solute affect the freezing point of a solution (or a solvent)?

Kf = Freezing Point Depression Coefficient ; M = Molarity of the solution (when solute is added) ; T0 = Freezing Point of the pure solvent; Tf = Freezing Point of the solution. Freezing point depression (the freezing point goes down) occurs when solute is added to the pure solvent.