In chemistry, the lever rule is a formula used to determine the mole fraction (x i) or the mass fraction (w i) of each phase of a binary equilibrium phase diagram. It can be used to determine the fraction of liquid and solid phases for a given binary composition and temperature that is between the liquidus and solidus line.

2020年11月26日 · If an alloy consists of more than one phase, the amount of each phase present can be found by applying the lever rule to the phase diagram. The lever rule can be explained by considering a simple balance.

The Lever Rule. The composition and amount of material in each phase of a two phase liquid can be determined using the lever rule. This rule can be explained using the following diagram. Figure \(\PageIndex{3}\) : Suppose that the temperature and composition of the mixture is given by point b in the above diagram.

The lever rule can be explained by considering a simple balance. The composition of the alloy is represented by the fulcrum, and the compositions of the two phases by the ends of a bar. The proportions of the phases present are determined by the weights needed to balance the system.

At 25°C, the specific volume of saturated liquid is 1.003 cm^3/g and the volume of saturated vapor is 43400 cm^3/g. What is the volume of a mixture with vapor fraction, x=0.3? The lever rule calculation is similar to that for calculating enthalpy.

Figure 5.5 illustrates how equations (5.1) can be realized graphically. This figure also helps us understand why these equations are called “the lever rule.”

The lever rule is a mathematical expression used to determine the relative proportions of different phases present in a material at a given temperature and composition. It is based on the principle of mass balance, where the sum of the fractions of each phase must equal to one.