{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Exam 2 - Version 380 Exam 2 mccord(50970 This print-out...

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

View Full Document Right Arrow Icon
Version 380 – Exam 2 – mccord – (50970) 1 This print-out should have 34 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points The length of an O H bond in water is ap- proximately 1. 1.0 m. 2. 1 . 0 × 10 4 cm. 3. 1 . 0 × 10 12 cm. 4. 1 . 0 × 10 8 cm. correct Explanation: In water the O H bond has a length of 9.6 × 10 11 m. 002 0.0 points EXTRA CREDIT QUESTION: A re- minder here to PLEASE bubble in your name, uteid, and your version number correctly. Do it now - don’t wait till the end of the exam. Also, a reminder that there is NO CLASS tomorrow (Friday, October 8th). That’s right, you get to SKIP chemistry class. I’ll see you on Monday, the 11th, and we’ll start up on Chapter 5. This question starts out at zero points but could very well increase after the grad- ing. Now, if more points are awarded (the curve) on this assignment, would you like them added to your score? 1. NO, leave my score alone, I prefer the lower score 2. YES, I would like the points and the higher score. correct Explanation: This should be a no-brainer. Most students want higher scores. If you picked yes, you got credit for the question and you got the extra points you asked for (if they were granted by your instructor). If you answered NO, you also got what you wanted... no points awarded. 003 10.0 points Which of the following compounds is non- polar? 1. BH 3 correct 2. O 3 3. NH 3 4. PH 3 5. PCl 3 Explanation: NH 3 , PH 3 and PCl 3 are tetrahedral with one lone pair and are therefore not symmet- ric; their polar bonds do not cancel, and the molecule is polar. O 3 is bent, with a lone pair on the central oxygen and is thus polar. BH 3 is trigonal planar. The polar B H bonds cancel and the molecule is not polar. 004 10.0 points Which of the following is diamagnetic? 1. O 2 2. O 2 3. O + 2 4. O 2 2 correct Explanation: All but O 2 2 are paramagentic (possess un- paired electrons). 005 10.0 points Which is the most polar molecule? 1. BF 3 2. H 2 O correct 3. CF 4
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
Version 380 – Exam 2 – mccord – (50970) 2 4. CH 4 5. Ar 6. CO 2 Explanation: H 2 O has angular molecular geometry. It is assymetrical and polar. 006 10.0 points Which of the following would have the highest melting point? 1. KCl 2. KI 3. KF correct 4. KBr 5. RbF Explanation: KF has the highest charge density. 007 10.0 points Draw the Lewis structure for CO. 1. O C 2. O C 3. O C 4. O C 5. O C 6. O C 7. O C 8. O C correct 9. O C 10. O C Explanation: C has 4 valence electrons; O has 6: C O Total number of valence electrons: C 1 × 4 e = 4 e O 1 × 6 e = 6 e 10 e O C or O C This configuration gives each atom a com- plete octet. 008 10.0 points Consider the following covalent bond radii: Single Double Triple C 77 pm 67 pm 60 pm N 75 pm 60 pm 55 pm O 74 pm 60 pm - S 102 pm - - What is the approximate length of the NN bond in nitrogen hydride (HNNH) using the table values?
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