If 1 mole of a non-volatile solute is dissolved in 1 kg of water, what is the expected freezing point depression? (2019)
Practice Questions
1 question
Q1
If 1 mole of a non-volatile solute is dissolved in 1 kg of water, what is the expected freezing point depression? (2019)
1.86 °C
3.72 °C
0.93 °C
2.0 °C
Freezing point depression (ΔTf) = i * Kf * m = 1 * 1.86 °C kg/mol * 1 mol/kg = 1.86 °C.
Questions & Step-by-step Solutions
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Q
Q: If 1 mole of a non-volatile solute is dissolved in 1 kg of water, what is the expected freezing point depression? (2019)
Solution: Freezing point depression (ΔTf) = i * Kf * m = 1 * 1.86 °C kg/mol * 1 mol/kg = 1.86 °C.
Steps: 7
Step 1: Understand that freezing point depression (ΔTf) is a way to measure how much the freezing point of a solvent (like water) is lowered when a solute is added.
Step 2: Identify the formula for freezing point depression: ΔTf = i * Kf * m.
Step 3: Recognize that 'i' is the van 't Hoff factor, which is 1 for a non-volatile solute (it does not dissociate in solution).
Step 4: Identify Kf, the freezing point depression constant for water, which is 1.86 °C kg/mol.
Step 5: Determine 'm', the molality, which is 1 mole of solute per 1 kg of solvent (water), so m = 1 mol/kg.
Step 6: Plug the values into the formula: ΔTf = 1 * 1.86 °C kg/mol * 1 mol/kg.
