AP Chemistry Unit 3

Which of these molecules could best be represented by the ball-and-stick model shown?

• BeH₂

• CO₂

• H₂O

• SO₂

What type of bonding is found within a water molecule?

• ionic bonding

• polar covalent bonding

• nonpolar covalent bonding

• hydrogen bonding

Dinitrogen monoxide, N₂0, has two double bonds. The general structure is N=N=O. What is the formal charge on the oxygen atom in this molecule?

• zero

• positive one (+1)

• positive two (+2)

• negative one (-1)

The Lewis structure of which compound is best represented with resonance structures?

• MgCl₂

• CO₂

• SO₃ ^2-

• OCl₂

The molecule shown above represents alanine, one of the simplest amino acids. This amino acid is considered nonessential to the human diet as it can be synthesized in the body from other compounds.

Which statement is correct concerning alanine?

• Each carbon atom is sp³ hybridized.

• The hybridization of the nitrogen atom is sp².

• All bond angles are approximately 109.50.

• The molecule contains 12 sigma and 6 pi bonds.

How many unbonded pairs of electrons are found on the alanine molecule?

• 0

• 1

• 3

• 5

Which bond is the most polar?

• F-O

• H-O

• Na -O

• Sn-O

The effect of lone pairs of electrons on molecular geometry is

• to push other atoms closer together because lone pairs are

  localized on only one nucleus, so they spread out more.

• to allow the other atoms to be further apart because lone pairs

  take up less space than bonding pairs.

• to create an aysmmetical distribution of the electrons within

  the atom, thus creating a polar molecule by creating dipoles.

• to help to create resonance structures through the formation of

  pi bonds.

What is the molecular geometry in the structure A?

• Tetrahedral

• Trigonal Planar

• Trigonal Pyramidal

• Octahedral

In paper chromatography, if water is the mobile phase, what kind of substance will move up the farthest?

• polar substance

• non polar substance