{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Exam 1-solutions - kad488 Exam 1 Lyon(53565 This print-out...

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

View Full Document Right Arrow Icon
kad488 – Exam 1 – Lyon – (53565) 1 This print-out should have 23 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. BE SURE THAT YOU HAVE BUB- BLED IN YOUR NAME AND EID COR- RECTLY. WE WILL BE UNABLE TO FIX VERSION NUMBER ERRORS WITH- OUT YOUR EXAM HARDCOPY AND IT WILL TAKE SOME TIME TO MAKE THE CORRECTION. IT MAY BE A WEEK OR MORE BEFORE YOU WILL KNOW YOUR EXAM SCORE IF YOU DO NOT COMPLETE THE BUBBLE SHEET COR- RECTLY. YOU MUST ALSO KEEP YOUR COPY OF THE EXAM AND MAKE IT AVAILABLE IF REQUESTED FOR ANY REASON THIS SEMESTER. 001 10.0 points Which one of the following statements is false? 1. Water dissolves many ionic solutes be- cause of its ability to hydrate ions in solu- tion. 2. Gases are generally more soluble in water under high pressures than under low pres- sures. 3. Gases are generally more soluble in water at high temperatures than at low tempera- tures. correct 4. Carbon tetrachloride (CCl 4 ) is more mis- cible with hexane (C 6 H 14 ) than it is with a polar solvent such as methanol (CH 3 OH). 5. As temperature increases, the solubilities of some solids in liquids increase and the sol- ubilities of other solids in liquids decrease. Explanation: The polarity of water allows it to hydrate the individual ions in the ionic solute. CCl 4 is non-polar and will be miscible with another non-polar liquid and not with a polar one. Increasing temperature makes salts with exothermic Δ H sol more soluble, but salts with endothermic Δ H sol less soluble. Gases are generally more soluble in water under high pressures than under low pressures because of Henry’s Law; as the pressure of a gas above a liquid increases, the concentration of the gas in the solution increases. 002 10.0 points A solution of 0.90 g of an unknown non- electrolyte in 300 mL of water at 27 C has an osmotic pressure of 38.4 torr. What is the molecular weight of this compound? (Ne- glect volume change due to solute, R = 0.0821 L · atm/mol · K) 1. 4.72 x10 5 g/mol 2. 3 . 78 × 10 2 g/mol 3. 1 . 52 × 10 3 g/mol 4. 1 . 46 × 10 3 g/mol correct 5. 5.81 x10 4 g/mol Explanation: T = 27 C + 273 = 300 K π = 38 . 4 760 atm π = M R T , where M is molar concentra- tion. M = mol unknown L soln = g unknown / MW unknown L soln g unknown R T = (0 . 90 g) parenleftBig 0 . 08205 L · atm mol K parenrightBig · (300 K) = 22 . 1535 g · L · atm mol MW unknown = g unknown R T π L soln = 22 . 1535 g · L · atm · mol 1 parenleftBig 38 . 4 760 atm parenrightBig (0 . 300 L) = 1461 . 52 g mol 1 003 10.0 points
Image of page 1

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

View Full Document Right Arrow Icon
kad488 – Exam 1 – Lyon – (53565) 2 Two aqueous solutions are separated by a semipermeable membrane. Solution A = 0.34 M KCl Solution B = 0.64 M KCl Which of the following statements is TRUE? 1. Cl ions flow from solution B to solution A. 2. For a reverse osmosis process, pressure must be applied to solution A. 3. K + ions flow from solution B to solution A.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern