Unit 2 - Week 6 Quiz

Which of the following molecules is non-polar despite containing polar bonds?

• Water (H₂O)

• Ammonia (NH₃)

• Carbon dioxide (CO₂)

• Chloroform (CHCl₃)

What is the molecular shape of a molecule with four bonding electron pairs and no lone pairs on the central atom?

• Trigonal planar

• Bent

• Pyramidal

• Tetrahedral

Which of the following best describes dispersion forces?

• They occur only between polar molecules.

• They are the strongest type of intermolecular force.

• They are present in all molecular substances.

• They involve hydrogen atoms bonded to oxygen, nitrogen or fluorine.

What makes a molecule polar?

• It has a high melting point.

• It is made up only of non-metals.

• It has an asymmetric shape and an uneven distribution of electrons.

• It has hydrogen bonds.

Which of the following molecules is capable of forming hydrogen bonds?

• Methane (CH₄)

• Hydrogen bromide (HBr)

• Methanol (CH₃OH)

• Carbon dioxide (CO₂)

A molecule with a trigonal pyramidal shape will have:

• Three bonding pairs and no lone pairs.

• Three bonding pairs and one lone pair.

• Four bonding pairs.

• Two bonding pairs and two lone pairs.

For methane (CH₄): State its molecular shape, number of bonding pairs, lone pairs, and approximate bond angle.

Explain how lone pairs affect the shape and polarity of water (H₂O).

Hydrogen fluoride (HF) has a significantly higher boiling point than hydrogen chloride (HCl). Explain why.

Methane (CH₄) contains polar bonds, yet the molecule is non-polar overall. Justify this statement.