MCAT Organic Chemistry Review


Practice Questions

1.    Within one principal energy level, which subshell has the least energy?

1.    s

2.    p

3.    d

4.    f

2.    Which of the following compounds possesses at least one σ bond?

1.    CH4

2.    C2H2

3.    C2H4

4.    All of the above contain at least one σ bond.

3.    A carbon atom participates in one double bond. As such, this carbon contains orbitals with:

1.    hybridization between the s-orbital and one p-orbital.

2.    hybridization between the s-orbital and two p-orbitals.

3.    hybridization between the s-orbital and three p-orbitals.

4.    no hybridization between the s-orbital and p-orbitals.

4.    The hybridizations of the carbon and nitrogen atoms in CN are:

1.    sp3 and sp3, respectively.

2.    sp3 and sp, respectively.

3.    sp and sp3, respectively.

4.    sp and sp, respectively.

5.    Which of the following hybridizations does the Be atom in BeH2 assume?

1.    sp

2.    sp2

3.    sp3

4.    sp4

6.    Two atomic orbitals may combine to form:

1.    a bonding molecular orbital.

2.    an antibonding molecular orbital.

3.    hybridized orbitals.

1.    I only

2.    III only

3.    I and II only

4.    I, II, and III

7.    Molecular orbitals can contain a maximum of:

1.    one electron.

2.    two electrons.

3.    four electrons.

4.    2n2 electrons, where n is the principal quantum number of the combining atomic orbitals.

8.    π bonds are formed by which of the following orbitals?

1.    Two s-orbitals

2.    Two p-orbitals

3.    One s- and one p-orbital

4.    Two sp2-hybridized orbitals

9.    How many σ bonds and π bonds are present in the following compound?

1.    Six σ bonds and one π bond

2.    Six σ bonds and two π bonds

3.    Seven σ bonds and one π bond

4.    Seven σ bonds and two π bonds

10.The four C–H bonds of CH4 point toward the vertices of a tetrahedron. This indicates that the hybridization of the carbon atom in methane is:

1.    sp.

2.    sp2.

3.    sp3.

4.    sp3d.

11.Why is a single bond stronger than a π bond?

1.    π bonds have greater orbital overlap.

2.    s-orbitals have more overlap than p-orbitals.

3.    sp3 hybridization is always unstable.

1.    I only

2.    II only

3.    I and III

4.    I, II, and III

12.The s character of the carbon atom in HCN is:

1.    25% s and 75% p.

2.    50% s and 50% p.

3.    33% s and 67% p.

4.    75% s and 25% p.

13.A resonance structure describes:

1.    the hybrid of all possible structures that contribute to electron distribution.

2.    a potential arrangement of electrons in a molecule.

3.    the single form that the molecule most often takes.

1.    I only

2.    II only

3.    I and II only

4.    I, II, and III

14.An electron is known to be in the n = 4 shell and the l = 2 subshell. How many possible combinations of quantum numbers could this electron have?

1.    1

2.    2

3.    5

4.    10

15.Compared to single bonds, triple bonds are:

1.    weaker.

2.    longer.

3.    made up of fewer π bonds.

4.    more rigid.