OZ - The atmosphere Flashcards
What is the composition of the atmosphere sometimes broken down by?
Its percentage composition by volume of dry air.
What does ‘dry air’ mean?
Air with no water vapour in it.
What is the percentage concentration of nitrogen in the air?
78%.
What does it mean that nitrogen has a percentage concentration of 78% in air?
For every 100 particles in the atmosphere, 78 of them will be N2.
What is the percentage concentration of oxygen in the air?
21%.
What is the percentage concentration of argon in the air?
~1%.
What does ppm stand for?
Parts per million.
How do you convert from ppm to percentage concentration?
Divide by 10,000.
How do you convert from percentage concentration to ppm?
Multiply by 10,000.
How many ppm of CO does the atmosphere contain?
0.1ppm.
How many ppm of nitrous oxide does the atmosphere contain?
0.3ppm.
What does the sun give out?
Electromagnetic radiation
Why does the sun give out electromagnetic radiation?
Because of the processes going on in its core.
How is electromagnetic radiation transmitted?
As waves.
What type of electromagnetic radiation does the sun give out?
Visible radiation (light) and infrared radiation (heat) along with a smaller amount of ultraviolet radiation.
Which EM radiation has the highest frequency&energy?
Gamma rays.
Which EM radiation has the lowest frequency&energy?
Radio waves.
Order the radiation on the EM spectrum from low to high frequency
Radio waves Microwaves Infrared Visible light Ultraviolet X-rays Gamma rays
Order the radiation on the EM spectrum from high to low frequency
Gamma rays X-rays Ultraviolet Visible light Infrared Microwaves Radio waves
What radiation does the Earth’s atmosphere absorb?
Some of the Sun’s infrared radiation and most of the ultraviolet radiation.
As well as absorbing some of the Sun’s radiation, what else does the Earth do with it?
The Earth’s surface also absorbs radiation from the sun and is warmed. It the re-emits radiation, mostly as infrared. The Earth emits much lower frequency radiation than the sun (because it’s much cooler).
What radiation does the Earth’s surface absorb?
The Earth’s surface also absorbs radiation from the sun and is warmed. It the re-emits radiation, mostly as infrared. The Earth emits much lower frequency radiation than the sun (because it’s much cooler).
What do UV and visible light radiation do to electrons?
Give them more energy.
Explain how UV and visible light radiation give electrons more energy
The electrons in molecules have fixed energy levels that they can jump between - these are called quantised energy levels.
When UV radiation or visible light hit a molecule of gas the electrons can absorb the energy and jump up and energy level. Because the energy needed for these changes is quantised too, only specific frequencies are absorbed.
If enough energy is absorbed bonds break, forming free radicals.
When happens if molecules absorb enough energy from UV radiation?
Bonds break forming free radicals.
When happens if oxygen molecules absorb enough energy from UV radiation?
If they absorb the right amount of UV energy they split into oxygen atoms or free radicals - this is the first step in the formation of ozone, O3.
What does the energy of light depend on?
Its frequency.
What equation can be used to calculate the energy from radiation?
E=hv
