Electronegativity, Intermolecular Forces, and Water

Question 1

What is Electronegativity?

Answer 1

Electronegativity represents the strength with which an element will attract a pair of shared electrons in a covalent bond.

Question 2

What does it mean when electronegativity is high/low?

Answer 2

When the En is high, the element has a high tendency to attract the electrons in a covalent bond (slightly negative). When En is low, it has a low tendency (slightly positive).

Question 3

What are Inermolecular Forces? What are they also known as?

Answer 3

Intermolecular forces are forces formed between molecules, also called Van der Waal forces.

Question 4

Name the three types of intermolecular forces.

Answer 4

1. London Forces
2. Dipole-Dipole Forces
3. Hydrogen Bonds

Question 5

Describe London Forces.

Answer 5

weakest of the three, exist between all atoms and molecules, caused by the attraction of electrons to protons in neighbouring atoms, very weak between noble gases and small non-polar molecules, slightly stronger between larger non-polar molecules b/c more atoms

Question 6

Describe Dipole-Dipole Forces.

Answer 6

Stronger than London forces, formed between the s+ and s- sides of polar molecules

Question 7

Describe Hydrogen Bonds.

Answer 7

Most biologically important, strongest IMF, very strong dipole-dipole force will form between H-atoms and neighboring N,O, or F atoms

Question 8

Explain cohesion in relation to water molecules.

Answer 8

Water molecules will form hydrogen bonds with other water molecules, also known as cohesion.

Question 9

Explain adhesion in relation to water molecules.

Answer 9

Water molecules will form hydrogen bonds with other polar molecules, also known as adhesion.

Question 10

Name some properties of water.

Answer 10

Colourless, oudorless, tasteless, polar molecule, heat capacity of 4.18 J/g ‘C, heat vaporization of 2.4 kJ/g, ice is less dense than liquid qwater because of crystal formation, water is densest at 4’C

Question 11

What is water important for biologically?

Answer 11

temperature regulation, moisture (eyes/lungs), lubrication (joints, saliva), chemcial reactions, diffusion/osmosis, as a solvent.

Question 12

What is the difference between the terms hydrophilic and hydrophobic?

Answer 12

Hydrophilic - polar or charged molecules that are strongly attracted to water.
Hydrophobic - non-polar molecules that are not strongly attracted to water.