Ozone: Intermolecular Forces

Question 1

Definition of electronegativity

Answer 1

Ability of an atom to attract a shared pair of electrons to itself

Question 2

What two factors affect electronegativity

Answer 2

1. Nuclear charge

2. Atomic radius

Question 3

How does nuclear charge affect electronegativity

Answer 3

Increased nuclear charge = increased electronegativity

Question 4

How does atomic radius affect electronegativity

Answer 4

Decreased atomic radius = increased electronegativity

Question 5

What do you atoms with similar electronegativities form

Give examples

Answer 5

Non-polar bonds

Eg. Cl2 , O2, I2

Question 6

What do you atoms with a big difference in electronegativity form

Answer 6

Polar bonds

Eg. H-Cl ( delta +ve H & delta -ve Cl )

H-O-H ( delta +ve H’s & delta -ve O )

Question 7

What causes POLAR molecular polarity

Answer 7

Unequal charge distribution

Eg. Cis Z ( CHCl=CHCl ) —> 2 delta +ve H on top and 2 delta -ve Cl on bottom

• CH3Cl —> 3 delta +ve H and 1 delta -ve Cl

Question 8

What causes NON-POLAR molecular polarity

Answer 8

equal charge distribution

Eg. Trans E ( CHCl=CHCl ) —> 1 delta +ve H on top & 1 on bottom and 1 delta -ve Cl on top & 1 on bottom

• CCl4 —> 4 delta -ve Cl

Question 9

What are the 3 main types of intermolecular forces

Answer 9

1. Permanent dipole-permanent dipole interactions
2. Instantaneous dipole induced dipole interactions
3. Hydrogen bonding

Question 10

Definition of a permanent dipole permanent dipole interactions

Answer 10

When attraction occurs between the partial positive ( delta +ve ) and negative ( delta -ve ) charges of neighbouring molecules

Question 11

Be able to draw a diagram showing the permanent dipole percent dipole interactions in hydrogen chloride

Answer 11

Look at sheet

Question 12

Definition of instantaneous dipole induced dipole interactions

Answer 12

• Relatively weak forces that increase in strength as the size of a molecule or atom increases
• Occur between atoms or molecules without permanent dipole is e.g. hydrocarbons

Question 13

Be able to draw a diagram showing instantaneous dipole induced dipole using two chlorine molecules

Answer 13

Look at sheet

Question 14

Definition of hydrogen bonding

Answer 14

Strongest type of intermolecular attractive force

Question 15

What three what three Bondings does hydrogen bonding only occur in

Answer 15

1. H-O
2. H-N
3. H-F

Question 16

Be able to draw a diagram of hydrogen bonding in water

hint = looks like mike mouse

Answer 16

Look at sheet

Question 17

State and explain to anomalous properties of ice caused by hydrogen bonding

Answer 17

1. Ice is less dense than water
   - molecules in ice held apart by hydrogen bonds
   - ice has an open lattice
2. Ice has a relatively high melting point
   - hydrogen bonds are relatively strong
   - hydrogen bond stronger than other intermolecular forces
   - more energy needed to overcome hydrogen bonding

Question 18

Explain the difference in density of liquid water and ice in terms of intermolecular bonds ( 6 )

Answer 18

1. Both have hydrogen bonding
2. Loan pair on oxygen…
3. Bonds to hydrogen with delta +ve charge on another molecule
4. Ice is less dense because
   - molecules get further apart
   - more ape structure ( more air between molecules )
5. Intermolecular bonds keep ice in a lattice
6. For same number of water molecules ice takes up more space than liquid water leading to lower density of ice