What happens to the osmotic pressure of a solution when a different solute is added?
Respuesta
Decreases
First decreases, then increases
Increases
None
Pregunta 2
Pregunta
What is the osmotic pressure of a 0.01 M solution of NaCl at 305 K?
Respuesta
190 mmHg
380 mmHg
0.25 atm
25 kPa
Pregunta 3
Pregunta
What is the molar mass of a nonelectrolyte solute that causes an osmotic pressure of 15 torr at 25 oC when 0.1 g of the unknown are dissolved in water to form a total volume of 125 mL?
Respuesta
991 g / mol
91 g / mol
2500 g / mol
None of the above
Pregunta 4
Pregunta
A careless experimenter placed a permeable membrane that allows the flow of both solute and solvent molecules through the membrane in the osmotic pressure measuring setup? Which of the following would be the result of his experiment?
Respuesta
The solution level would be higher than the solvent level.
The solvent level would be higher than the solution level.
The two levels would remain the same because both solute and solvent can flow through the membrane.
None of the above
Pregunta 5
Pregunta
Which of the following best explains a lower than expected boiling point?
Respuesta
Vapor pressure lowering
Freezing point depression
The use of a volatile solute.
None of the above
Pregunta 6
Pregunta
Which of the following would explain a higher than expected boiling point elevation?
Respuesta
The thermometer is incorrect.
The solute is an electrolyte.
The solution is a nonelectrolyte.
The solution is very viscous.
Pregunta 7
Pregunta
What is the boiling point of a 1.2 m aqueous solution of a nonelectrolyte? The Kb of water is 0.51 oC kg / mol.
Respuesta
100.6 degrees C
99.4 degress C
0.612 degrees C
None
Pregunta 8
Pregunta
Which colligative property predicts the boiling point elevation phenomenon?
Respuesta
Osmotic pressure
Freezing point depression
Viscosity elevation
Vapor pressure lowering
Pregunta 9
Pregunta
Which of the following is not true about freezing points?
Respuesta
They are a property only of the pure solvent and, therefore, cannot be changed.
They can be increased by the addition of a non-volatile solute.
They can be decreased by the addition of a non-volatile solute.
The can be increased by the addition of a volatile solute.
Pregunta 10
Pregunta
How can we rationalize a situation where the vapor pressure of a solution is greater than that of the pure solvent despite Raoult's law that predicts a lower vapor pressure?
Respuesta
We forgot to include Herny's law in our analysis.
Entropy dictates that there is a random chance of violating any law.
Experimental error
Raoult's law is only valid for nonvolatile solutes, the solute must be a volatile one.