Intermolecular Forces Flashcards
What are the different types of intermolecular forces
Ion-dipole, ion induced dipole forces, dipole-dipole forces, Hydrogen bond, dipole induced dipole forces, London forces
What influences the strength of ion-dipole forces
- size of ion
- strength of dipole
- distance between ion and dipole
What Is a hydrogen bond
A force of attraction between a hydrogen covalently bonded into a molecule, with a small, strong electronegative atom N, O or F and the lone pair electrons of a neighbouring molecule on the N, O or F atom
What is the strongest van der waal force
Hydrogen bonding
What are the two conditions for hydrogen to apply
- Hydrogen needs to be covalently bonded to a high electronegative atom such as N, O, or F
- There must be a lone pair on another or the same highly electronegative atom of another molecule:
What is the relationship between density and intermolecular forces
Generally the stronger the intermolecular forces the higher the density (except water)
What Influences London forces
Generally London forces increase with increasing molecular mass (increase in size and number of electrons)
How does molecular form influence intermolecular forces
The greater the contact surface the stronger the intermolecular forces
What does iso-electronic mean
Molecules of the same number of electrons with a similar size
What is viscosity
The amount of resistance that a substance displays against flow
How does intermolecular forces influence viscosity
The stronger the intermolecular forces the greater the viscosity
What is thermal expansion
The volume of a substance increase as it’s temperature increases
What is thermal conductivity
The ability of a substance to conduct heat
What causes solids to heat up
When a solid is placed in a candle flame the heat energy from the candle is transferred to the solid. The tightly packed molecules then start to vibrate. The vibration are transferred from one atom or molecule to the next. The average Kinect of energy of the particle increases as and causes a temperature increase in the substance
