Ch6- Shapes of Molecules

Question 1

Explain the Electron Pair Repulsion Theory:

Answer 1

Question 2

What is the bond angle and shape for a molecule with: 2 bonding pairs, and 0 lone pairs?

Answer 2

Question 3

What is the bond angle and shape for a molecule with: 3 bonding pairs, and 0 lone pairs?

Answer 3

Question 4

What is the bond angle and shape for a molecule with: 4 bonding pairs, and 0 lone pairs?

Answer 4

Question 5

What is the bond angle and shape for a molecule with: 6 bonding pairs, and 0 lone pairs?

Answer 5

Question 6

What is the bond angle and shape for a molecule with: 3 bonding pairs, and 1 lone pairs?

Answer 6

Question 7

What is the bond angle and shape for a molecule with: 2 bonding pairs, and 2 lone pairs?

Answer 7

Question 8

What is the bond angle and shape for a molecule with: 2 bonding pairs, and 0 lone pairs?

Answer 8

Question 9

What is the bond angle and shape for a molecule with: 4 bonding pairs, and 0 lone pairs?

Answer 9

Question 10

What is electronegativity?

Answer 10

Question 11

In terms of electronegativities, what is the difference non-polar bonds and polar bonds?

Answer 11

Question 12

Dipoles:

Answer 12

Question 13

What are Intermolecular forces?

Answer 13

Intermolecular forces are weak attractive forces between dipoles of different molecules

Question 14

What are London Forces also known as?

Answer 14

Van der Waal’s forces.

Question 15

What are the three different types of intermolecular forces?

Answer 15

1. Induced dipole-dipole interactions (London Forces)
2. Permanent dipole-dipole interactions
3. H-bonding

Question 16

What are induced dipole-dipole interactions (LF)?

Answer 16

Question 17

What factors affect the strength of London Forces?

Answer 17

Question 18

What are permanent dipole-dipole interactions?

Answer 18

Question 19

What are hydrogen bonds?

Answer 19

Question 20

What is H-bonding like in ice?

Answer 20

Each water molecules is H-bonded to 4 others in tetrahedral formation. Ice has a diamond like structure. Its volume is larger than the liquid making it.

Question 21

What are anomalous properties of water?

Answer 21

Question 22

How does melting and boiling affect the H-bonds in water?

Answer 22

Melting breaks the rigid lattice arrangement of H-bonds
Boiling completely breaks H-bonds

Question 23

What are properties of Simple Molecules?

Answer 23

1. Low MP + BP: small amount of energy needed to overcome weak intermolecular forces of attraction holding the molecules together in simple molecular lattice. The strong covalent bonds between atoms in molecules don’t break / change state.
2. Non-conductivity of electricity: no mobile charged particles
3. Solubility: non-polar substances are soluble in non-polar solvents. The formation of weak intermolecular forces between non-polar solvent + molecules in lattice helps to break down + substance dissolves.

Non-polar substances tend to be insoluble in polar solvents. There is little attraction between polar solvent and molecules in lattice as intermolecular forces within polar solvent are too strong to overcome.

Polar substances may dissolve in polar solvents depending on strength of dipole. The attraction between molecules in lattice and polar solvent has to be strong enough to break down simple molecular lattice if substance is to dissolve.