Unit 11 Section 5: Vapor Pressure of Solutions

T/F: Henry's Law refers to both solute & solvent, while Raoult's Law specifically applies to the solute

FALSE; Henry's Law refers specifically to the solute, while Raoult's Law applies to both solvent and solute

the vapor pressure of the solvent above an ideal solution (pA) is always ____________ than the vapor pressure of the pure solvent (PA0).

Lower

he relationship between the composition of a solution and the vapor pressure of the solvent and the solute above the solution is given by _____________

Raoult's Law

T/F: Raoult's law and Henry's law actually are the same for an ideal solution

TRUE

What is the mole fraction (X-sub-A) equal to in terms of partial pressure?

The mole fraction of solvent A above the solution is equal to its partial pressure divided by the total vapor pressure above the solution

What is the formula for Dalton's law of partial pressures?

The total vapor pressure above a solution is equal to the sum of the vapor pressures of solvent A (pA) and solute B (pB)

the vapor pressure of the solution is ____________ than the vapor pressure of the pure solvent except when the solute is more volatile than the solvent

lower

Henry's law constant k is equal to the vapor pressure of the pure solute when concentration is expressed as a _____________.

mole fraction

Describe Henry's Law

the direct proportionality between the pressure of a gas above a solution and the concentration of the gas in the solution.

What is the full equation for Raoult's Law of vapor pressures? Describe each term

the vapor pressure of a solution in terms of the vapor pressures of the pure components and the composition of the solution.

What conclusion can be drawn from Raoult's Law of vapor pressures for a pure solute and pure solvent?

the vapor pressure of each component of the solution is equal to its mole fraction (XA) in the solution times the vapor pressure of the pure component at that same temperature.

In Raoult's Law, PB° represents _____________. What would the formula look like?

the vapor pressure of the pure solute

In Raoult's Law, PA° represents _______________. What would the formula look like?

the vapor pressure of the pure solvent

When is the vapor pressure of the solution higher than the vapor pressure of the solvent?

when the solute is more volatile than the solvent

Define an ideal solution

where solute-solvent attractive forces are equal in strength to solute-solute and solvent-solvent attractive forces.