Effect Of Intermolecular Forces

Question 1

Density

Answer 1

Density is mass per volume. The closer the particles are packed together the higher the density. The stronger the intermolecular forces, the greater the density of the substance. Solids have the highest intermolecular forces and therefore the highest density

Question 2

Molecular mass

Answer 2

As the molecular mass increases, the number electrons also increases. The strength of the Van der Waals forces increase for molecules with a larger molecular mass

Question 3

Van der Waals forces: melting and boiling points

Answer 3

If they are both non - polar or both polar: talk about molecular mass, then having more/stronger Van der Waals forces, therefore more energy…

If they have different polarities: one polar, one non polar:
Talk about dipole dipole forces being stronger than that of London forces… therefore more energy is required…

Question 4

Melting and boiling points of substances of small molecules (covalent structure) vs large molecules (covalent network structures)

Answer 4

In giant structures such as diamond, graphite and silicon dioxide, melting and boiling points are high due to the large amount of energy needed to break the many strong covalent bonds

Question 5

Viscosity

Answer 5

Viscosity is the amount of resistance that a substance displays against flow.
The stronger the intermolecular force, the greater the viscosity. The greater the viscosity, the slower it flows

Question 6

Thermal expansion

Answer 6

Is the increase in volume of a substance as its temperature increases
Stronger intermolecular forces means less thermal expansion. Since solids will expand less than liquids at the same temperature

Question 7

Thermal conductivity

Answer 7

The ability of a substance to conduct heat

Conductivity increases as intermolecular forces increase