### Post-Laboratory Questions**Due after Laboratory Experiment**1. **Question:** While performing the Dumas experiment, if the outside of the flask were not completely dry (Part I), how would this affect the calculated molar mass of the unknown volatile liquid? Would it be higher or lower? Explain.2. **Question:** While determining the pressure during the Dumas experiment, if the barometric pressure reported were lower than the actual vapor pressure (Part I), how would this error affect the calculated molar mass of the unknown volatile liquid? Explain.3. **Question:** While determining the volume during this experiment (Part II), if the total volume of the flask were incorrectly reported as 125 mL, how would this error affect the calculated molar mass of the unknown volatile liquid? Explain.4. **Question:** Calculate the number of moles of Argon gas contained in a 4.00 dm³ container at 620 kPa and 25.0°C. If the gas is Helium instead of Argon, will the answer change? Explain.5. **Question:** In the Dumas method for determining the molar mass of an unknown volatile liquid, a sample of a volatile liquid that boils below 100°C is vaporized in a boiling water bath and the mass of the vapor required to fill the flask is determined. The following data was collected: - **Table: Collected Data:** | Parameter | Value | |------------------------------|--------------------------| | Flask Volume | 100.0 + 1000.0 + 79.6 mL = 279.6 mL | | Mass of Flask + Cap | 143.85 g | | Mass of Flask + Condensed Liquid | 144.95 g | | Mass of Condensed Liquid | 1.10 g | | Temperature of Water Bath (°C) | 84.1 °C | | Barometric Pressure (atm) | 0.985 atm | a. **Sub-question:** What is the molar mass of the unknown? b. **Sub-question:** What will its temperature be when the pressure is 1.20 atm and the volume is 250.0 mL?6. **Question:** Chemical analysis of an unknown compound shows that it contains 64

Since you have asked multiple questions, we will solve the first one for you. For remaining…

1. While performing the Dumas experiment, if the outside of the flask were not completely dry (Part I), how would this affect the calculated molar mass of the unknown volatile liquid? Would it be higher or lower? Explain.

1. While performing the Dumas experiment, if the outside of the flask were not completely dry (Part I), how would this affect the calculated molar mass of the unknown volatile liquid? Would it be higher or lower? Explain.

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

Specify whether the calculated mass percent of water would be too high, too low, or unchanged as a result of each of the following experimental conditions. Justify your answers. a. The heating was insufficient to remove all of the water from the hydrated salt. b. Some of the sample spattered out of the crucible onto the laboratory bench during the heating.
Choose all that apply. In Experiment 4, we use a mixture of 50% water and 50% isopropyl alcohol as the solvent. Why do we use this mixture rather than using pure water as the solvent? O The isopropyl alcohol is needed to act as a catalyst for the reaction to occur. There would be too much of a reactant that it would distort the reaction rate. t-butyl chloride is has low solubility in pure water. The hydrolysis reaction would occur too quickly in pure water to have good measurements for analysis. The isopropyl alcohol is necessary for the reaction to occur.
It is emphasized in the procedure that the water bath should be continuously stirred while heating and cooling the sample. What will happen if the water bath was not stirred? Identify its effect to the related derived data
A student rushed through this experiment. Describe the effect that the following procedural changes would have on the percent recovery of acetanilide. Briefly explain the basis of each answer.(a) Rather than adding 0.5-mL portions of boiling solvent to the acetanilide, the student added 5-mL portions of boiling solvent.(b) The student did not pre-heat the gravity filtration apparatus.(c) The student forgot to cool 5 mL of solvent in Part 5 and washed the crystals with room-temperature solvent.
A student forgot to add the mass of the unknown solute in trial 1 to the mass of the solute that was weighed for trial 2 and then added to the cyclohexane-solute solution used in trial 1. How would this omission affect the calculated molecular weight of the solute?
A student following the published Experiment 5 procedure mixes 1.702 g 4-aminophenol with an 2.6 mL acetic anhydride. Calculate the moles of 4-aminophenol used. Use the formula weights and density (if needed) provided in the procedure. Report your answer to 3 significant figures.
What is the sample dilution in the fifth tube of a 10-fold dilution?
why was ice bath and room tempertature used instead of hot bath?
Can someone help me out here? There first time I calculated the theoretical yield for this experiment I got 0.540g with the given values but I actually used the wrong values. I added the new values above and the units used are mols. I can't seem to figure out or remember how I calculated 0.540g with the (3.00x10^-3 mols)(0.0098 mols). Can someone please help me by telling me how to get grams by using the equation (0.002995 mols)(0.0105mols)? I know the value should be relatively close to 0.540g but every time I try to calculate it, my answer is no where near 0.540g. Please answer clearly and concisely. Also please make sure to read the question carefully, thank you!