The Atmosphere Flashcards
What percentage of the atmosphere is nitrogen
78%
What is the value and units for planks constant?
6.63 x 10-34 J/Hz
What formula links plancks constant, frequency and energy
Energy = planck’s constant x frequency of light
What are the 4 aspects a molecule behaviour associated with its energy
Translation, rotation, vibration and electronic
In terms of a molecules behaviour, what is translation?
The molecule moving around as a whole
In terms of a molecules behaviour, what does electronic mean?
The movement of electrons from on energy level to another
Rank the energy activities from lowest energy requirement to highest
Translation, rotation, vibration, electronic
What part of the light spectrum affects electronic energy changes
Visible and ultra-violet
What part of the light spectrum results in rotating a molecule?
Microwave
What is the another way of referring to the breaking of bonds?
Bond fission
What is homolytic fission
When the electrons shared in a covalent bonds are evenly split between the two atoms resulting in the formation of free radicals
What do you call an atom with an unpaired electron
A free radical
What is heterolytic fission
When a covalent bond breaks and the electrons all go to one atom, resulting in a negative and positive charged ion
Why are free radicals so reactive?
Because filled outset shells are more stable than unfolded one, so they tend to grab electrons from other atoms to fill their outer energy level
What is the first stage of a free radical reaction called and how do you recognise one
Initiation, and usually a photodissocition reaction occurs resulting in free radical products
What is the second stage of a free radical reaction called and how do you recognise one
Propagation, wear free radicals react with other molecules to create more free radicals. Free radicals reactants and products
What is the final stage of a free radical reaction called and how do you recognise it
Termination, when two radicals react together resulting in non radical products
How do halogen atoms affect the boiling point of a hydrocarbon
The larger the halogen atom (so the lower down the group) the higher the boiling point
Name the 4 regions of the atmosphere, lowest to highest
Troposphere, stratosphere, mesosphere and thermosphere
Why were CFC’s so popular?
They were very unreactive, low toxicity and low flammability
What refrigerant did CFC’s replace and why?
Ammonia and because it was toxic and foul smelling
What free radical breakdown ozone?
Chlorine
In what part of the atmosphere do CFC’s breakdown?
Stratosphere
What are the advantages and disadvantages to replacing CFC’s with hydrochlorofluorocarbons?
Advantage, HC bonds are broken down in the troposphere before it reaches the stratosphere
Disadvantage, it’s a green house gas and contributed to global warming
What are the advantages and disadvantages to replacing CFC’s with alkanes?
Advantage, alkanes don’t contain chlorine
Disadvantage, flammable and a green house gas
What cause CFC’s to breakdown in the stratosphere?
UV radiation
Explain why heating up a molecule speeds up rate of reaction
More molecules have energy greater than the activation energy which is the energy molecules need to react when they collide
Why does increasing concentration increase the rate of reaction
There are more collisions per unit time resulting in faster reaction
Describe what it is meant by the term nucleophile
A species with a lone pair which forms a covalent bond with a positively charged carbon atom
