Question

State whether you would use Raoult's law or Henry's law to perform vapor-liquid equilibrium calculations for each component in the following liquid Mixtures: (For Raoult's law type "R", and for Henry's law type "H" as your answer) (a) water and dissolved nitrogen (b) hexane , octane and decane (c) CO2 and water in club soda or any other carbonated beverage

Answer 1

To perform vapor-liquid equilibrium calculations for water and dissolved nitrogen, Henry's law ('H') should be used. For a mixture of hexane, octane, and decane, Raoult's law ('R') is appropriate, and for CO2 dissolved in water, as in club soda, Henry's law ('H') would be used again.

Step-by-step explanation:

We use different gas laws to perform vapor-liquid equilibrium calculations based on the behavior of components in a mixture. For Raoult's law, we consider an ideal solution where the partial pressure of a component is directly proportional to its mole fraction in the solution. This law is typically applied to solutions where all components are volatile liquids. On the other hand, Henry's law is used when a gas is dissolved in a liquid, and the gas's solubility is directly proportional to its partial pressure above the solution. With this understanding:

• (a) Water and dissolved nitrogen would use 'H' (Henry's law) because nitrogen is a gas dissolved in a liquid.
• (b) A mixture of hexane, octane, and decane would use 'R' (Raoult's law) as all are volatile liquid components in nearly ideal behavior.
• (c) CO2 and water in club soda would use 'H' (Henry's law), with CO2 being the dissolved gas in a liquid.

It is important to consider the intermolecular interactions and the deviation from ideality to determine which law to apply for accurate vapor-liquid equilibrium calculations.

Answer 2

Use Raoult's law for an ideal solution of similar components (b) and Henry's law for dilute solutions or where a gas is dissolved in a liquid (a) and (c).

Step-by-step explanation:

When determining which law to use for vapor-liquid equilibrium calculations, the choice between Raoult's law and Henry's law depends on the nature of the components in the solution and their interactions. Raoult's law is typically used for components in an ideal solution, where the intermolecular forces between dissimilar molecules are similar to those between similar molecules.

(a) For a solution of water and dissolved nitrogen, Henry's law is used since nitrogen is a non-volatile solute in water and the solution is dilute. Answer: "H"

(b) For a mixture of hexane, octane, and decane, which are similar non-polar hydrocarbons that would form nearly ideal solutions, Raoult's law is applicable. Answer: "R"

(c) For CO2 dissolved in water in club soda or other carbonated beverages, Henry's law is used because CO2 is a gas dissolving in a liquid at relatively low concentrations. Answer: "H"