The relative error can be reduced If a more precise thermometer is used. Assume

Question

The relative error can be reduced If a more precise thermometer is used. Assume that with the more precise thermometer you can determine the temperature to within plusminus 0.02 degree C. If the measured freezing-point depression with such a thermometer is 9.52 degree C, what molality is determined for this solution? What is the relative error in the molality as determined with this more precise thermometer? Cyclohexanol, C_6H_11 OH, is sometimes used as the solvent in molecular weight determinations by freezing point depression. If 0.253 g of benzoic acid. C_6H_5COOH, dissolved in 12.45 g of cyclohexanol, lowered the freezing point of pure cyclohexanol by 6.55 degree C. what Is the molal freezing-point constant of this solvent?

Explanation / Answer

2.

a. molality = dTf/iKf

                  = 9.52/1 x 1.86

                  = 5.12 m

This calculation is done for aqueus solution.

% relative error in molality = 0.002%

1. molalrity of solution = 0.253/100.16 x 0.01245 = 0.203 m

Kf = dTf/i.m

    = 6.55/1 x 0.203

    = 32.266 oC/m

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.