Respuesta :
Answer:
The Kb for cyclohexane is 2.79 °C/m
Explanation:
Step 1: Data given
Mass of Paradichlorobenzene = 2.00 grams
Mass of cyclohexane = 22.5 grams
Boiling point of the solution = 82.39 °C
Boiling point of pure cyclohexane = 80.70 °C
Molar mass of Paradichlorobenzene = 147 g/mol
Step 2: Calculate moles Paradichlorobenzene
Moles Paradichlorobenzene = mass / molar mass
Moles Paradichlorobenzene = 2.00 grams / 147 g/mol
Moles Paradichlorobenzene = 0.0136 moles
Step 3: Calculate molality
Molality = moles Paradichlorobenzene / mass cyclohexane
Molality = 0.0136 moles / 0.0225 kg
Molality = 0.605 molal
Step 4: Calculate Kb
Kb = change in boiling point / molality of solution
⇒ Change in boiling point = 82.39 - 80.70 = 1.69 °C
⇒ molality = 0.605 molal
Kb = 1.69 °C / 0.605 molal = 2.79 °C/m
The Kb for cyclohexane is 2.79 °C/m
Answer:
The Kb for cyclohexane is 2.80°C/m
Explanation:
delta T = 82.39 - 80.70 = 1.69 °C
Moles C6H4Cl2 = 2.00 g/ 147.0 g/mol= 0.0136
molality = 0.0136 mol / 0.0225 Kg = 0.604
1.69 = 0.604 x kf
kf = 2.80
The Kb for cyclohexane is 2.80°C/m
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