Exam 1-solutions - Version 118 Exam 1 mccord (51625) 1 This...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Version 118 Exam 1 mccord (51625) 1 This print-out should have 26 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points Ethyl alcohol (CH 3 CH 2 OH) is/is not soluble in water. 1. is; ethyl alcohol exhibits dipole-dipole and H-bonding interactions with water. correct 2. is not; ethyl alcohol exhibits dispersion forces which are insufficient for dissolving. 3. is not; ethyl alcohol is an ionic compound with a hydroxide group and hydroxides are insoluble. 4. is; all organic molecules are soluble in water. Explanation: The oxygen on ethyl alcohol has two lone pairs and two polar bonds. Thus, it can form dipole-dipole and H-bonding interac- tions with polar water. 002 10.0 points Solution A contains 0.5 grams of solute A and solution B contains 0.5 grams of solute B (both A and B are nonelectrolytes). Other than the solutes, the solutions are identical (volume, temperature, etc .). Now you mea- sure the osmotic pressure of each solution and find that the osmotic pressure of solution B is twice that of solution A. What is the relation- ship between the molecular weights of solutes A and B? 1. The molecular weight of solute A is twice that of solute B. correct 2. The molecular weight of solute A is four times that of solute B. 3. The molecular weight of solute B is twice that of solute A. 4. The molecular weight of solute B is four times that of solute A. 5. The molecular weight ratio cannot be determined from this experiment. Explanation: Because the solution with B has twice the osmotic pressure, it must also have twice the number of dissolved particles (number of moles of B). The only way to have more moles for B (knowing the same mass of A and B was used) is that B has a smaller molecular weight than A. For the osmotic pressure to be ex- actly twice that of A, the molecular weight of B must be half that of A which is the same as A being twice that of B. 003 10.0 points Carbon Dioxide 3 1 4 2 A B 200 250 300 350 400 10 10 1 10 2 10 3 10 4 Pressure,bar Temperature, K A sample of carbon dioxide is stored at 10 4 bar and 250 K. This sample is then decompressed to 10 bar at constant temper- ature. Then, at constant pressure it is heated to 400 K. Next, it is compressed at con- stant temperature to 200 bar. According to the phase diagram, how many phase transi- tions has the carbon dioxide gone through, and what is its final state? 1. 3, gas 2. 2, supercritical fluid correct 3. 2, liquid Version 118 Exam 1 mccord (51625) 2 4. 2, gas 5. 3, supercritical fluid Explanation: Navigate through the diagram through each process. In the first decompression, the solid is decompressed and becomes a liquid and then a gas (2 phase transitions). Upon heating, it becomes a supercritical fluid (no phase transitions)....
View Full Document

This note was uploaded on 07/12/2011 for the course GOV 365L taught by Professor Liu during the Spring '08 term at University of Texas at Austin.

Page1 / 9

Exam 1-solutions - Version 118 Exam 1 mccord (51625) 1 This...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online