Data and Calculations: Pure Water Methanol in Water Volume of Water (ml) 10.00 10.00 Mass of Methanol (g) Freezing Point ('C) Freezing point depression AT- Calculate the molality m (K, = 1.86 °C/m for water) 1.00 Tsolvent = 1 AT, = Tsolvent – Tsotution = AT; = Kr.m → m = AT;/Kf = Tsotution= -4.5 m = moles methanol/ Kg solvent → moles methanol m x Kg solvent = Calculate number of moles Calculate the molar mass of methanol moles methanol = mass methanol / molar mass methanol → molar mass methanol = mass methanol / moles methanol → molar mass methanol = 1.00 g/ moles methanol % error (actual molar mass of methanol = %error =[ ]actual – experimental| / actual ] x 100% 32.04 g/mol) Question: 1. What is the freezing point of a solution prepared by dissolving 20 g of ethanol (Molar mass = 46 g/mol) in 120 mL of water? The freezing point depression constant Kf for water is 1.86 °C/m. Assume density of water is 1 g/ml.

Data and Calculations: Pure Water Methanol in Water Volume of Water (ml) 10.00 10.00 Mass of Methanol (g) Freezing Point ('C) Freezing point depression AT- Calculate the molality m (K, = 1.86 °C/m for water) 1.00 Tsolvent = 1 AT, = Tsolvent – Tsotution = AT; = Kr.m → m = AT;/Kf = Tsotution= -4.5 m = moles methanol/ Kg solvent → moles methanol m x Kg solvent = Calculate number of moles Calculate the molar mass of methanol moles methanol = mass methanol / molar mass methanol → molar mass methanol = mass methanol / moles methanol → molar mass methanol = 1.00 g/ moles methanol % error (actual molar mass of methanol = %error =[ ]actual – experimental| / actual ] x 100% 32.04 g/mol) Question: 1. What is the freezing point of a solution prepared by dissolving 20 g of ethanol (Molar mass = 46 g/mol) in 120 mL of water? The freezing point depression constant Kf for water is 1.86 °C/m. Assume density of water is 1 g/ml.

Chemistry & Chemical Reactivity

10th Edition

ISBN:9781337399074

Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel

Publisher:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel

Chapter13: Solutions And Their Behavior

Section: Chapter Questions

Problem 106SCQ

See similar textbooks

Similar questions

The lattice enthalpy of sodium chloride, H for NaCl(s)Na+(g)+Cl(g) is 787 kJ/mol; the heat of solution in making up 1 M NaCl(aq) is +4.0 kJ/mol. From these data, obtain the sum of the heats of hydration of Na+ and Cl. That is obtain the sum of H values for Na+(g)Na+(aq)Cl(g)Cl(aq) If the heat of hydration of Cl is 338 kJ/mol, what is the heat of hydration of Na+?
A gaseous solute dissolves in water. The solution process has H=15 kJ. Its solubility at 22C and 6.00 atm is 0.0300 M. Would you expect the solubility to be greater or less at (a) 22C and 1 atm? (a) 18C and 6 atm? (a) 15C and 10 atm? (a) 35C and 3 atm?
You make 20.0 g of a sucrose (C12H22O11) and NaCl mixture and dissolve it in 1.00 kg water. The freezing point of this solution is found to be 0.426C. Assuming ideal behavior, calculate the mass percent composition of the original mixture, and the mole fraction of sucrose in the original mixture.
An aqueous solution containing 0.250 mole of Q, a strong electrolyte, in 5.00 102 g water freezes at 2.79C. What is the vant Hoff factor for Q? The molal freezing-point depression constant for water is 1.86C kg/mol. What is the formula of Q if it is 38.68% chlorine by mass and there are twice as many anions as cations in one formula unit of Q?
The solubility of ethylene (C2H4) in water at 20 C and 0.300 atm pressure is 1.27 104 molal. (a) Calculate the Henrys law constant for this gas in units of molal/torr. (b) How many grams of ethylene are dissolved in 1.00 kg water at 20 C if the pressure of the gas is 500 torr?