Answer:
(a) Raoult's Law: The relative lowering of vapor pressure of a solution containing a non-volatile solute is equal to the mole fraction of the solute.

(b) Differences between Ideal and Non-Ideal Solutions:
• Ideal Solutions: Obey Raoult's law at all concentrations; ΔH_mix = 0, ΔV_mix = 0; Intermolecular forces (A-B) are equal to (A-A) and (B-B).
• Positive Deviation: Vapor pressure is higher than expected; ΔH_mix > 0, ΔV_mix > 0; A-B interactions are weaker than A-A or B-B.
• Negative Deviation: Vapor pressure is lower than expected; ΔH_mix < 0, ΔV_mix < 0; A-B interactions are stronger than A-A or B-B.

(c) Numerical Calculation:
1. For Cane Sugar:
• Mass of solute = 5g, Mass of water = 95g = 0.095 kg
• Moles of sugar = 5 / 342 = 0.0146 mol
• Molality (m1) = 0.0146 / 0.095 = 0.1537 mol/kg
• ΔTf = 273.15 - 271 = 2.15 K
• Kf = ΔTf / m1 = 2.15 / 0.1537 = 13.98 K kg/mol
2. For Glucose Solution:
• Moles of glucose = 5 / 180 = 0.0278 mol
• Molality (m2) = 0.0278 / 0.095 = 0.2926 mol/kg
• ΔTf = Kf × m2 = 13.98 × 0.2926 = 4.09 K
• Freezing point of glucose solution = 273.15 - 4.09 = 269.06 K

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Chemistry 5-Mark Long Answer Questions

Chemistry 5-Mark Long Answer Questions

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