Section 1 Flashcards
Define Energy.
The capacity or ability to do work.
Define Matter.
Something that cannot be created nor destroyed and occupies space.
Define Isothermal.
Reaction where the temperature does not change due to taking place in a reservoir.
Define an open system.
A system in which energy and matter can travel in an out freely.
Define Closed system
A system in which energy can move in a out freely but matter is restricted.
Define isolated system.
A system in which energy and matter cannot pass freely in and out.
Define surroundings.
Everything outside of the system.
Define reservoir.
Environment of a system that will not hon age by any addition do to the vastness of it.
Define kinetic energy.
Physical energy transferred from motion.
Define potential energy
The merge stored within the bonds.
Does the bulk phase refer to kinetic or potential energy?
Kinetic energy.
Does chemical/internal energy refer to kinetic or potential energy?
Potential Energy
Define heat.
Energy that can be stopped by an insulator.
Define work.
Energy that cannot be stopped by an insulator.
Explain an state function.
A value that can be looked up. The end result is the only thing that matters.
Explain a path function.
Works step by step toward the end result. Requires calculations.
Explain Enthalpy
A thermodynamic quantity equivalent to the total heat content of a system. It is equal to the internal energy of the system plus the product of pressure and volume.
Define Adiabatic.
A change where q equals 0 and can be forced by an insulator.
Explain exothermic.
An exterior release of thermal energy.
Explain endothermic.
Takes energy from the surroundings for the reaction to occur.
Define Gibbs Free Energy.
Predicts whether a process will occur spontaneously.
What is the equation for obtaining Wmax for explosive processes?
Wmax = DeltaH x (1-(Tcold/Thot)
What is the equation to find Wmax from a non reactive system?
Wmax = Delta G
What are the wavelengths limits for the thermal IR range?
5-50um
Explain the difference between the sun’s emissions spectrum and the earth’s emission spectrum.
Sun has shorter wavelengths which are hotter and emit more energy. The earths wavelengths are longer and provide less energy.
Peak wavelength = 2897/T
What is fixed carbon?
CO2 that is utilized and stored in plants by photosynthesis
Compared to a CO2 molecule, what is the effect of each sulphur hexafluoride molecule.
Approximately 24000 times
Compared to a CO2 molecule, what is the effect of each CFC molecule?
Approximately 12500 times.
Compared to a CO2 molecule, what is the effect of each molecule of nitrous oxide?
Approximately 200 times for the short term and 320 for the long term.
What do we know about the net effect of high clouds on global warming?
High clouds have a net warming effect.
What do we know about the net effect of low clouds on global warming?
Low clouds have a net cooling effect
Give the wavelength range for the atmospheric window.
8-13 um
What is the life time of an aerosol particle
Depends on rainfall. Typically lasting a couple of weeks.
Which areas of the globe are experiencing the greatest increase in temperature?
The Arctic and Antarctic poles suffer the greatest temperature increase.
Do we know yet if the formation of clouds works as a positive feedback process for global warming?
No, this has not yet been confirmed.
Give two ways of raising the temperature of an ideal gas.
- Heating the ideal gas.
2. Increasing the pressure of an ideal gas.
Which measurable quantity changes when the K.E. Of molecules increases?
Temperature.
List the molecules that result in the greenhouse effect.
H2O, CO2, CH4, O3, N2O
List the gases that result in the enhanced greenhouse effect.
H2O, CO2, CH4, O3, N2O, CFCs (HCFCs), SF6
List the three modes of vibration possible with molecules.
- Symmetrical Stretching
- Anti-symmetric stretching
- Angle bending
What are the wavelengths and vibrations that occur at these wavelengths for CO2?
Angle bending -14.0um
Anti symmetric stretching - 4.2um
What is the average release of CO2 per person in industrial countries?
5 tonnes per year.
What are the three main sources of CO2 production?
- Fossil fuel combustion/cement production
- Forests decomposition
- Oceans
What is a negative feedback?
Good thing, net cooling effect.
What is a positive feedback?
Bad thing, net warming effect.
What are the main sources and sinks of SF6 in the atmosphere?
Source - gas used as an insulator.
Sink - photo decomposition in the stratosphere when introduced to UV.
What are the permanent and temporary sinks for CO2?
Permanent - Deep oceans
Temporary - Shallow oceans, plants
Describe the two fold nature of the atmospheric life time of carbon dioxide.
The length the carbon dioxide takes to be permanently deposited out of the atmosphere compared to how much is being released.
Define carbon dioxide fertilization, and describe its effect.
Carbon dioxide in the atmosphere that is absorbed by plants allowing them to grow faster. Plants absorb more than they release.
Describe the important sinks for methane in the atmosphere, and give the average lifetime for a methane molecule in the atmosphere.
Sinks in the atmosphere for methane are free radical hydroxide. Average lifetime of methane in the atmosphere is one decade.
What are the six important sources for methane?
Wetlands, ruminant animals, melted permafrost, landfills, natural gas, clatherates in ocean depths.
List the sources and sinks for atmospheric nitrous oxide.
Sources - tropical soils, oceans, fertilization, landfills, nylon production, new grasslands.
Sinks - photo degrading the the stratosphere
Is water vapour in the atmosphere a positive or negative feedback?
Positive. The water vapour in the atmosphere causes the earth to heat up producing more water vapour.
In the formula Tavg=Css/R what does each variable mean?
Tavg - Average residence time of a gas in the atmosphere.
Css - Steady state of concentration of the gas in the atmosphere.
R - Rate of release of the gas into the atmosphere.
What are the sinks of N2O in the atmosphere?
Stratosphere - UV causes photochemistry degrading.
What are the main issues with CFCs and HCFCs in the atmosphere?
- very stable
- absorb directly in the atmospheric window (8 - 14um)
- each molecule is 10000 times as effective as CO2
What are the sources and sinks for CFCs/HCFCs in the atmosphere?
Sources - Anthroprogenic
Sinks - Stratospheric absorption of UV.
What are the relative percentages of GHGs?
40% oceans 60% due to other gases - CO2 60% - CH4 20% - N2O 6% - CFCs 3% - O3 10%
What are the sources of N2O in the atmosphere?
Tropical soils Oceans Fertilizers Landfills Nylon production New grasslands
