Ozone Story Flashcards
What are the 3 types of intermolecular bonds
1) instantaneous dipole- induced dipole
2) permanent dipole-permanent dipole
3) hydrogen bonds
How do instantaneous dipole- inducer dipole bonds work?
1) electrons are always moving causing charge density to change making instantaneous dipoles
2) this can induce a dipole be attracted towards it creating an instantaneous- induced bond
(The bonds get broken and remade because electrons keep moving)
How does a molecules shape affect its intermolecular bonds?
More places for id-id bonds to form if it had a longer chain
Branch chains can’t get as close
Why does a molecules size and mass effect boiling point?
The bigger the molecule the larger electron cloud which means it forms stronger id-id bonds
What do bonds need to be in order to have a pd-pd bond?
Polar
When can hydrogen bonding happen and why?
When a hydrogen is attached to a fluorine, nitrogen, or oxygen.
Very electronegative with hydrogen - high charge density on the H
What does electronegative mean?
Tendency to attract electrons and form negative ions
Two ways hydrogen bonds affect how a substance behaves
1) hydrogen bonding is a very strong intermolecular bond giving the substance a high melting point as it’s hard to over come
2) soluble in water - can form bonds with the water making it soluble
How can an experiment show differences in bond strengths
Energy is absorbed to break bonds when a liquid evaporates
so you can measure the temperature change in order to see how easily a liquid evaporates
and what type of intermolecular bonds it’s likely to form
What is the collision theory
Particles must collide with:
- correct orientation
- enough kinetic energy to react (activation energy)
How would increased temp change the Boltzmann distribution graph?
- moves it to the right
- reduces hump
- more molecules with enough activation energy to react
How do catalysts affect reaction rate?
- lowers activation enthalpy by providing an alternative pathway (a different way for bonds to be broken and remade)
- so more particles have enough energy to react
How does pressure and concentration affect reaction rate?
- particles are closer together on average
- collide more often so have more chances to react
How does temperature affect reaction rate?
- particles have more energy so more likely to react when they collide
- move faster - collide more frequently
How can you use experiments to find out rate of reaction?
Measure loss of reactant of formation of product at regular intervals
What is a catalyst
A catalyst increases rate of reaction by providing and alternative reaction pathway with lower activation enthalpy
Catalyst is chemically unchanged at the end and reformed
Two types of catalyst
Homogeneous - same state heterogeneous - different state
How do homogeneous catalysts work?
- by forming intermediated
- the activation enthalpy needed to make intermediates and form the product is lower than reactants straight to products
- catalyst reformed again
How many jumps does a homogeneous catalyst reaction have?
2 from making intermediates
Do boiling points of haloalkanes increase or decrease down the group?
Increase
Stronger id-id bonds because molecules are bigger due to more electron levels
Why are carbon-halogen bonds polar
How does this affect the molecule?
High difference in electronegativity
Carbon becomes electron deficient so it can be attacked by a nucleophile
What is a nucleophile?
Give an example
An electron pair donor
OH-
NH3
What is nucleophilic substitution
A functional group in a compound is replaced by another
Because a nucleophile attacked a partially positive carbon
What do haloalkanes react with to form alcohols
OH-
