Simple Covalent Molecules

Question 1

How are simple molecular structures formed

Answer 1

Simple molecular structures are formed when atoms share electrons through covalent bonds.

Question 2

examples of substances with simple molecular structures

Answer 2

gases: O2, N2
H2O, C2H5OH (ethanol)
Solids with low melting and boiling points (e.g. iodine, I₂)

Question 3

what is Intermolecular forces of attraction

Answer 3

Intermolecular forces of attraction are the forces between molecules

Question 4

As relative molecular mass (Mᵣ) increases, the molecules become larger and heavier TF?

Answer 4

T

Question 5

As relative molecular mass (Mᵣ) increases, the molecules become larger and heavier, resulting in:

Answer 5

Higher melting and boiling points

Question 6

explain why substances with a simple molecular structures are gases or liquids, or solids with low melting and boiling points

Answer 6

• Weak intermolecular forces: Simple molecular structures have weak intermolecular forces. These forces are responsible for holding molecules together in a substance.
• Low molecular weight: Simple molecular structures often have low molecular weights, which means they have fewer electrons and a smaller size. This results in weaker intermolecular forces and lower melting and boiling points.
• High molecular mobility: Simple molecular structures have high molecular mobility, which means the molecules can move freely and easily. This makes it easier for the substance to change state from solid to liquid to gas.

Question 7

explain why the melting and boiling points of substances with simple molecular structures increase, in general, with increasing relative molecular mass

Answer 7

• Increased intermolecular attraction: As the relative molecular mass increases, the molecule becomes larger and has more electrons. This results in a greater attraction between molecules.
• Increased molecular surface area: As molecules become larger, their surface area increases, allowing for more points of contact between molecules. This increased surface area enables stronger intermolecular interactions, resulting in higher melting and boiling points.