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

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

See similar textbooks

Similar questions

A 0.751-g sample of protein is dissolved in 50.0 mL of solution, and the solution exhibits an osmotic pressure of 4.1 torr at 25oC. Calculate the molar mass of protein. (R = 0.08206 L.atm/(mol.K); 1 atm = 760 torr; assume the protein is nonelectrolyte)
Boiling Point ElevationThe boiling point of a solution INCREASES with the number of dissolved solute particles. This is summarized by the expression: Tb = m i KbWhere: Tb is the increase in the boiling point = Tb(solution) - Tb(pure solvent) m is the molality of the solution = (# moles solute / kg solvent) i is the "van't Hoff" factor = (# moles of solute particles / mole of solute) For nonelectrolytes: i = 1 For strong electrolytes: i = number of (cations + anions) For weak electrolytes: 1 < i < number of (cations + anions) Kb is the boiling point elevation constant. It depends only on the SOLVENT. Example:Na2SO4 is a soluble salt. It breaks into two Na+ cations and one SO42- anion in solution.i = 2 + 1 = 3 CH3COOH is a weak acid. It breaks into a few CH3COO - anions and a few H+ cations. 1 < i < 2.
Calculate how much NaCl (in w/w%) is required to lower the freezing point for salt solutions of the freezing point of water to -4.00 degrees Celsius. Kf= 1.86 deg kg mol-1. Calculate the molality to reach 4.00 degrees Celcius and convert it to %w/w using the molar mass of NaCl
An experiment was conducted to determine the effect of glucose on the freezing point of water. Experimental data showed thatthe freezing point depression of water in solution was –2.6°C when 1.0 g of glucose was dissolved in 10g of solvent. Calculatethe expected freezing point for such solution and compare the expected freezing point to the value found experimentally. Give aplausible explanation for any discrepancies. (M.W. of glucose= 180.16g/mol; i=1). Show all your work.
Complete the freezing point depression table below: Mass / Volume added Added reagent Molecular Weight van't Hoff Factor molality Freezing Point 20.0 g NaCl 25.0 g Li2SO4 10.0 mL 0.150 M ethanol Kf (°C/m) of water: 1.86 Freezing Point of Water, °C: 0.0 SOLVENT: 100 g water
6. What volume of conc. HCl (density 1.19g/cm3, 38% HCl by weight) is required to make up 18L of 0.50N HCl. 7. Sulfuric acid, H2SO4 has a density of 1.198g/cm3 containing 27.0% by weight. Calculate the molar and molal concentration
Aqueous ethanol solutions are prepared by mixing measured weights of assayed ethanol and organic-free water. What is the molality of an aqueous solution that is 45.1 % ethanol, C2H5OH , by mass? Atomic Mass: C=12.01 ; H=1.008 ; O= 16.0 Express your answer in two decimal places. Do not write the unit.
At a certain temperature the vapor pressure of pure acetyl bromide (CH,COB1) is measured to be 257. mmHg. Suppose a solution is prepared by mixing 136. g of acetyl bromide and 88.2 g of chloroform (CHCI,). Calculate the partial pressure of acetyl bromide vapor above this solution. Round your answer to 3 significant digits. Note for advanced students: you may assume the solution is ideal. I| mmHg Explanation Check 2022 McGraw Hill LLC. All Rights Reserved. Terms of Use | Privacy Center Ac stv A
A sports drink formulation can be prepared by mixing the ingredients in the quantities shown in the table below. Calculate the freezing point of this drink formulation. (Kffor water is 1.86 °C kg mol-1 and the molar mass of sucrose is 342.3 g mol-¹). Ingredient Mass (g) NaCl 1.2 0.49 KCI Sucrose (C12H22011) 60 1000 water O a. -0.38 °C O b.-0.43 °C O c. -0.10 °C O d. -0.32 °C O e. -0.75 °C Which ONE of the following saturated aqueous salt solutions will contain the highest total concentration of ions at 25°C? a. AgCl = 1.8 x 10-10) (Ksp (Ksp = 3.9 × 10-11) O b. CaF2 OC. Ag2CO3 O d. COCO3 (Ksp (Ksp = 1.0 x = 8.1 x 10-12) 10-10) The highest amount of solid Cul2 will dissolve in 1.0 L of an aqueous solution of: a. 0.5 M CaCl2 b. 0.5 M Cu(NO3)2 O c.0.5 M Cul2 O d. 0.5 M NH4I O e. 0.5 M CuCl2
A 1.00 molal aqueous solution of trichloroacetic acid (CCl3COOH) is heated to its boiling point. The solution has the boiling point of 100.18°C. Determine the van’t Hoff factor for trichloroacetic acid. (Kb for water = 0.512 K kg mol-1)
The molal boiling point elevation constant K = 1.15 °C-kg-mol for a certain substance X. When 14.4 g of urea the solution boils at 145.4 °C. Calculate the boiling point of pure X. Be sure your answer has the correct number of significant digits. °C X a ((NH,), CO) S are dissolved in 150. g of X,