Chapter 3.7 - Forces Acting Between Molecules Flashcards
Name the 3 types of intermolecular forces :
- Van der Waals forces
- Dipole Dipole (permanent dipole)
- Hydrogen bonding
Explain hydrogen bonding
-hydrogen bonding only happens when hydrogen is covalently bonded to fluorine, nitrogen or oxygen
Explain how hydrogen bond has a huge effect on the property of the substance:
Substances with hydrogen bond have high boiling point and mp
State the strongest type of interaction that occurs between molecules of hydrogen peroxide and water
Hydrogen bonding
Name the strongest attractive force between two ammonia molecules.
Hydrogen bonding
State the strongest type of intermolecular force between hydrogen fluoride molecules.
Hydrogen bonding
In terms of intermolecular forces, suggest the main reason why phosphine is almost insoluble in water. (1)
Phosphine does not form hydrogen bonds with water
Explain, in terms of bonding, why the boiling point of fluorine is very low (1)
Weak van der waals forces between molecules
Fluorine and iodine are elements in Group 7 of the Periodic Table.
Explain why iodine has a higher melting point than fluorine. (2)
- iodine has more electrons,
- stronger van der waals forces between molecules
State the strongest type of intermolecular force in a sample of NHF2
Hydrogen bonding
State the strongest type of intermolecular force holding the water molecules together in the ice crystal
Hydrogen bonding
State the strongest type of intermolecular force in methane
Van der waals forces
Give one reason why the melting point of ice is higher than the melting point of methane.(1)
Hydrogen bonding is stronger than van der waals forces
State the strongest type of intermolecular force in water and in hydrogen sulfide
Water - hydrogen bonding
Hydrogen sulfide - van der waals forces
Explain why the boiling point of water is much higher than the boiling point of hydrogen sulfide
Hydrogen bonding is stronger than van der waals forces
Suggest the strongest type of intermolecular force between CCl2F2 molecules
Van der waals forces
The boiling point of AsH3 is –62.5 °C and the boiling point of NH3 is –33.0 °C. Suggest why the boiling point of AsH3 is lower than that of NH3
- Weak van der waals forces between molecules of AsH3,
- ammonia has hydrogen bonding,
- van der waals forces is weaker than hydrogen bonding
Explain the trend in the boiling points of the hydrogen halides from HCl to HI
HI = 930C HCL = 400C
- bp increases with the increasing in Mr
- van der waals forces
