1.4: Quiz 1A Key

Chem 8A: Organic Chemistry - Brief Course · LibreTexts

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      1. Please indicate true (T) or false (F) for the following statements based on lecture materials (2 pts each):
    __F__ Based on the number of valence electrons, a carbon atom can have either three, four or five bonds.
    __F__ If a carbon atom is sp2 hybridized, then the bond angles will be 180˚.
    __T__ LiCl contains an ionic bond.
    1. For each of the following condensed structures, indicate how many lone pairs each molecule has. (1 pt each, put your numerical answer in the box provided)
    CH3CH2OH CH3Cl HONH2 CH3CH2CH3
    1b 1b 1b 1b

    1. (3 pts each) Draw a Lewis structure for the following species (including any lone pairs):
    a) H2CO b) [CH3NH3]+
    2a.png 2b.png
      1. (2 pts) Covalent bonds may be polar or nonpolar. What property of the atoms forming a given bond determines this?

        electronegativity

      2. Give an example for each of the following bond types (2 pts each):
        (Note: your answer does not need to be a valid Lewis structure, you can just show two atoms in a bond.)
    non-polar covalent bond polar covalent bond
    3b 3b

    F-F

    H-H

    based on the lecture notes and page 8 of the textbook,
    C-H is also acceptable

    C-F

    C-Cl

    C-Br

    C-O

    F-H

    O-H

    N-H
      1. (4 pts) Briefly explain why a carbon atom cannot have more than 4 bonds?
        Carbon has 4 valence electrons and 4 orbitals that can each accept an electron to make 4 bonds (2 e- each). More than 4 bonds would violate the octet rule because all orbitals are full.
      2. (4 pts) Draw a structure of a molecule that has an sp-hybridized carbon that is directly attached to an sp2-hybridized carbon and clearly label these two carbon atoms with the hybridization. (Note: Your molecule can have any atoms in addition to these two carbon atoms. There are several possible answers, but make sure that your answer is a valid structure showing any hydrogens or lone pairs for full credit.)

    4b.png

    1. Multiple choice (2 pts each, put your letter answer in the box provided)

    What is the approximate value of the Br-C-Br bond angles in carbon tetrabromide, CBr4?

    1. 5a.png90˚
    2. 109˚
    3. 120˚
    4. 180˚

    Which of the following describes a carbon-carbon triple bond?

    1. 5b.pngthree pi bonds
    2. one sigma bond and one pi bond
    3. two sigma bonds and one pi bond
    4. one sigma bond and two pi bonds
      1. For the following molecule, give the hybridization of the indicated atom.
        (2 pts each, put your answer in the box provided)


    6a.png

    1. (2 pts each) What are the formal charges on the indicated nitrogen and oxygen atoms in the molecule shown below?

    6b.png

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    1.4: Quiz 1A Key is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.