1. What is the difference between molarity and molality?
Answer: Molarity is the number of moles of solute per liter of solution, while molality is the number of moles of solute per kilogram of solvent.
2. Explain how to calculate the molality of a solution.
Answer: Molality (m) is calculated by dividing the moles of solute by the mass of the solvent in kilograms.
3. Define the term “mole fraction” in the context of solutions.
Answer: Mole fraction is the ratio of the number of moles of a component to the total number of moles in the solution.
4. What is the significance of vapor pressure in solutions?
Answer: Vapor pressure determines the tendency of a solvent to vaporize, which is affected by the presence of solute particles.
5. Explain Raoult’s Law and its application in ideal solutions.
Answer: Raoult’s Law states that the vapor pressure of a solution is directly proportional to the mole fraction of solvent present, assuming ideal behavior of the solution components.
6. How does Raoult’s Law differ between ideal and non-ideal solutions?
Answer: In ideal solutions, Raoult’s Law holds true perfectly, whereas in non-ideal solutions, deviations from Raoult’s Law occur due to interactions between solute and solvent molecules.
7. What is the relative lowering of vapor pressure?
Answer: The relative lowering of vapor pressure is the ratio of the decrease in vapor pressure of the solution compared to the vapor pressure of the pure solvent.
8. Define depression of freezing point.
Answer: Depression of freezing point is the lowering of the freezing point of a solvent due to the presence of a non-volatile solute.
9. How is the elevation of boiling point determined in a solution?
Answer: The elevation of boiling point is determined by the increase in the boiling point of a solvent caused by the presence of a non-volatile solute.
10. Explain how colligative properties are related to the number of solute particles.
Answer: Colligative properties, such as vapor pressure lowering, freezing point depression, and boiling point elevation, depend on the number of solute particles rather than the nature of the solute.
11. What is abnormal molar mass, and how is it determined experimentally?
Answer: Abnormal molar mass refers to the apparent molar mass of a solute as determined from colligative properties, which may differ from its actual molar mass due to association or dissociation in solution.
12. Define van’t Hoff factor and its significance.
Answer: The van’t Hoff factor (i) represents the ratio of moles of particles in solution to moles of solute dissolved, taking into account dissociation or association of solute molecules. It’s significant in calculating colligative properties accurately.
13. How does the boiling point of a solution containing a non-volatile solute compare to that of the pure solvent?
Answer: The boiling point of the solution is higher than that of the pure solvent due to the presence of the non-volatile solute.
14. Describe the composition plots for ideal and non-ideal solutions.
Answer: In ideal solutions, composition plots show linear relationships between properties like vapor pressure and composition. In non-ideal solutions, curves or deviations from linearity are observed due to interactions between solute and solvent.
15. What factors can cause deviations from ideal behavior in solutions?
Answer: Factors such as solute-solvent interactions, solute-solute interactions, and changes in temperature and pressure can cause deviations from ideal behavior in solutions.
16. How does the addition of a solute affect the colligative properties of a solution?
Answer: Addition of a solute decreases the vapor pressure, increases the boiling point, and decreases the freezing point of the solvent compared to its pure state.
17. Explain the concept of percent by mass in solutions.
Answer: Percent by mass is the ratio of the mass of solute to the total mass of solution, expressed as a percentage.
18. Discuss the significance of vapor pressure-composition plots in understanding solution behavior.
Answer: Vapor pressure-composition plots show how the vapor pressure of a solution changes with the composition of the solvent and provide insights into the interactions between solute and solvent molecules.
19. How do you calculate the vapor pressure of a solution using Raoult’s Law?
Answer: The vapor pressure of a solution can be calculated using Raoult’s Law by multiplying the vapor pressure of the pure solvent by the mole fraction of the solvent in the solution.
20. What are some applications of colligative properties in real life?
Answer: Colligative properties are used in various applications such as antifreeze solutions in automobiles, determination of molecular weights of substances, and in pharmaceutical formulations to control osmotic pressure.