Intermolecular Forces
Define intermolecular force
The invisible forces between molecules/particles that hold them together
Which state of matter has the highest density? Explain why.
Solids because they have the strongest intermolecular forces so they are very close together and compacted
Name the following phase changes:
- liquid --> solid
- liquid --> gas
- solid --> liquid
- gas --> liquid
- freezing
- evaporation
- melting
- condensation
Elephants eat about 200 kilograms of food a day. How many grams is this?
200,000 grams
How many hydrogen bonds does this molecule have?
https://drive.google.com/file/d/14D5U80r7c4Pf8Ru0JM_hFQWgCeU8w0_G/view?usp=sharing
1
Solid - close together, pattern
Liquid - more spread out
Gas - very spread out
Describe the difference between endothermic and exothermic changes
Endothermic changes absorb energy (heat), exothermic changes release energy (heat)
Identify the following phase changes as fusion or vaporization:
- evaporation
- melting
- freezing
- condensation
- evaporation (vaporization)
- melting (fusion)
- freezing (fusion)
- condensation (vaporization)
Explain why intermolecular forces and kinetic energy are inverse (as one goes up, the other goes down) of each other
Intermolecular forces hold molecules/particles together. When they molecules/participles are given kinetic energy, they use the energy to pull away from their IMFs, weakening then strength of them
Identify 2 differences between liquids and gasses
- liquids have stronger IMFs
- liquids have less kinetic energy
Name the two processes happening at part D of this phase change diagram:
https://drive.google.com/file/d/1UTjB7BaU5pbTDMswP20fcA32Qiwsttmn/view?usp=sharing
<-- is condensation
--> is evaporation
Calculate the amount of heat needed in calories, to vaporize 68.2g of heptane.
5217.3cal
Name 4 physical properties substances with STRONG intermolecular forces would have
- high boiling point
- high melting point
- high density
- low vapor pressure
- if liquid, high viscosity
- if liquid, slow evaporation
- if liquid, high surface tension
What type of particles make up an ionic solid? Name 2 physical properties of an ionic solid based on this
Made of ionic particles (metal + non-metal). Conductive, brittle, higher melting point
Boiling occurs when _______________ equals _______________
Vapor pressure, atmospheric pressure
Calculate the amount of heat needed in Joules, when 4.84mol of carbon tetrachloride melts.
13068J
Rank the following in order of increasing intermolecular forces:
- dense liquid
- amorphous solid
- molecular solid
- not dense liquid
- ionic solid
- gas
- metallic solid
gas --> not dense liquid --> dense liquid --> amorphous solid --> molecular solid --> ionic solid --> metallic solid
What type of particles make up a molecular solid? Name 2 physical properties of a molecular solid based on this
Covalent particles (non-metals). Not conductive, brittle, low melting point
Label all of the letters (except for b and g) on this diagram:
https://drive.google.com/file/d/1GJf5_Dsy4xv0R9nbMF-ZDQd05Ekoybjl/view?usp=sharing
a - melting/freezing
c - solid
d - liquid
e - gas
f - triple point
Calculate the amount of heat given off in kilocalories when 82.4kg of water condenses
44496kcal