Question 1

What is vapor-liquid equilibrium (VLE)?

Accepted Answer

VLE describes the distribution of components between liquid and vapor phases at equilibrium. The relationship is governed by Raoult's law for ideal mixtures or activity coefficients for non-ideal.

Question 2

What is the bubble point?

Accepted Answer

Bubble point is the temperature or pressure at which the first vapor bubble forms from a liquid mixture. At bubble point, the liquid is saturated and about to vaporize.

Question 3

What is the dew point in VLE?

Accepted Answer

Dew point is the temperature or pressure at which the first liquid drop condenses from a vapor mixture. At dew point, the vapor is saturated and about to condense.

Question 4

What is an activity coefficient?

Accepted Answer

Activity coefficient (γ) corrects for non-ideal liquid behavior. γ=1 for ideal mixtures. Values >1 indicate positive deviation from Raoult's law, <1 indicates negative deviation.

VLE Calculator

VLE Calculator

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T-xy Diagram at P = 760 mmHg