Prelaboratory Questions Name Laboratory Section Show your work, include units, and report the correct number of significant figures for all calculations. 1. The molal freezing point depression constant (K;) for p-dichlorobenzene is 7.10°C/m and its normal freezing point (f.p.) is 53.10°C.When 0.304 g of an unknown solute is dissolved in 3.78 g of p-dichlorobenzene, the f.p. is lowered to 49.60°C. Refer to the Introduction and Data Sheet to solve the following problems. a) The f.p. depression (AT;) is °C. b) Calculate the molality (m) of the solution. c) Calculate the number of moles of solute in the solution. d) Calculate the molar mass of the unknown solute. (continued on next page) 101

Prelaboratory Questions Name Laboratory Section Show your work, include units, and report the correct number of significant figures for all calculations. 1. The molal freezing point depression constant (K;) for p-dichlorobenzene is 7.10°C/m and its normal freezing point (f.p.) is 53.10°C.When 0.304 g of an unknown solute is dissolved in 3.78 g of p-dichlorobenzene, the f.p. is lowered to 49.60°C. Refer to the Introduction and Data Sheet to solve the following problems. a) The f.p. depression (AT;) is °C. b) Calculate the molality (m) of the solution. c) Calculate the number of moles of solute in the solution. d) Calculate the molar mass of the unknown solute. (continued on next page) 101

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...

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5 L山 When 1.06 g of a certain molecular compound X are dissolved in 85.0 g of dibenzyl ether ((C,H,CH,),0), the freezing point of the solution is measured to be 0.9°C. Calculate the molar mass of X. If you need any additional information on dibenzyl ether, use only what you find in the ALEKS Data resource. Also, be sure your answer has a unit symbol, and is rounded to 1 significant digit. 自 OL Check Save For Later Submit Assignment O2022 McGraw Hill LLC. AlI Rights Reserved. Terms of Use Privacy Center Accessibility EPIC 中Xe MacBook Pro F2 F3 F4 F7 F8 F10 6-5 #3 3. 2 $ 一 8 dele R. A C. W alt alt option 10 command option 1Q15
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2. Using the data given below, calculate the percentage of KHP in the impure sample. The molar mass of KHP is 204.219 g/mol. Molarity of NaOH Solution: Mass of Unknown: Volume of Water Used to Dissolve Unknown: Volume of NaOH Used to Reach Equivalence Point: Percent of KHP: 0.1955 M 1.1801 g 30.00 mL 17.01 mL % Stolal Vol)
Name Time M T W R F The freezing point of pure benzene (CH,) is 5.50°C. The freezing point of a solution containing 5.00 g of an unknown non-dissociating solute in 444 g of benzene is 5.07°C. K, of benzene = 4.90°C/m. Show complete calculations for each question below. 1. What is the freezing point depression for this solution?
1. The freezing point datas of pure water and 150 grams of H20 that includes 10 g of sucrose (C12H22011) are given below. According to these datas, calculate the molecular weight of 10 g sucrose (C12H22011) dissolved in 150 g of H2O. a. Freezing point of pure water, Tf = 0 °C Freezing point of solution, Tf = -0. 34 °C Freezing point depression, ATf = ... (0- (-0.34)) = 0.34°C Molal freezing point depression of water, Kf = •.1.86°C kg/mol b. Molality of solution, m = . c. Molecular weight of solute, MWs = .. %3D 2. Find the theoretical molecular weight of solute in literature and calculate the percentage error in molecular weight. MWs, real = Error%=
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Match the following. Drag the terms on the left to the appropriate blanks on the right. Reset Help 0.020 MNH4 Cl solution that is most strongly dependent upon pressure 1. 0.0050 MCO2 2. - highest boiling point 0.050 MC6H12O6 (aqueous) 3. - solution of ionic compound with highest freezing point 0.010 mAl(NO3)3 0.050 mNaCi 4. - solution with AT, 0.026° C 5. - largest van't Hoff factor
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