Final

• prevent waste

• minimize the number of materials

• generate substances that are not toxic

• use less energy

• renewable materials

• design materials that can be safely decomposed or recycled after use

• All chemists try to create and or follow more environmentally-friendly approaches to do chemistry

• non superimposable mirror images

• c has four different rests

• to find out which of the enantiomers is harmful, you must test every stereotype

• exponents

• logarithms

• scientific notation

• significant figures: numbers of decimal places should be similar to the one with the least

• question (why, how?)

• research

• hypothesis

• experiment

• analysis/ conclusion

=> observation have to be repeatable

=> Analyze results and share findings and conclusions: publish in peer-reviewed journals to verify that

• work is unique

• a significant contribution to scientific literature

• experiments were were optimal performed

• results and conclusions are consistent with the experimental conditions and dats

• explanation of observed behavior based on significant data

• e.g. daltons atomic theory

• simple statement/ summary of observed behavior

• gas laws, law of definite proportions

physical change:

• substance doesn’t change its chemical make-up

• phase change from solid =>liquid => gas => plasma

Chemical change

• substance changes its chemical make-up

• e.g. reaction or decomposition

• forces between the particles are strong enough to limit free motions => they just vibrate

• stable, definite shape and volume

• ion, atoms, molecules

• almost incompressible substances, that conforms to the shape of its container

  
  

• a compressable substance that completely fills its containers

• a partially ionized gas (with a charge)

• least common on earth, most common on universe

troposphere, stratosphere, mesosphere, thermosphere, exosphere

human sources:

• energy, landfills, ruminants, waste, rice, biomass burn

natural sources

• wetlands, termites, oceans, hydrates

• oceans

• soils

• tropospheric hydroxide

• stratospehric loss

• when writing formulars, the element that is on the left side of the periodic table goes generally first

  • exception: C/H organic compounds

• name rules: first element keeps its name, second gets an “ide” at the end

  • prefixes before the name of each element tells how many atoms are in the molecule

boyle’s law: for a constant amount of gas, the pressure and volume will inversely affect each other

Charles law: for a constant amount of gas, temperature and volume will directly affect each other

Avogadros law: each volume of any gas contains the same amount of particles, regardless of the identify of the gas => also same percentage at the same temp. and pressure

• it arises when the layers from warm and cool air change/ inverse

• instead of warm air on the ground, there is cool air on the ground => warm air from the ground switched its position with the cool air

• warm air is rising in the sky, cool air stays low with all the pollution in it => pollution cant vanish

• smog: fog + pollutants

• CO => from incomplete combustion

• SO2 => from burning coal (S is inside coal)

• NO2 => reaction from the engine: 1/2 N2 + O2 + heat from engine => NO2

• O3 => photochemical reactions, caused by sunlight through interactions with pollutants: e.g.: NO2 + sunlight => NO + O*

  • O* + O2 => O3

• Particulate Matter: carbon left from burning fossil fuels, pollen, dust

• harmful exhaust gases (CO + NO2) enter catalytic converter

• catalyst, a ceramic honeycomb coated with platinum, palladium, rhodium causes a chemical reaction to convert harmful gases into less harmful ones (CO2 + H2O)

• but sulfur will be poisonous for catalytic converter

• CO is colorless, odorless, tasteless gas

• CO remains closer to the ground in colder temperatures

• CO tightly binds to the iron molecule of hemoglobin, which hinders oxygen from binding to it. Therefore less oxygen can bind => and people die

• kills bacteria, microorganisms, parasites

  • pools, instead of chlorine treatment

  • clean and deodorize air and fabrics

  • hospital operation rooms

  • food production (Magarine, butter)

• Acts as a bleach

  • in pulp and paper mills

• ozone layer is between the stratosphere and troposphere. It protects the earth from UV-radiation

• O2 + UV-C => 2 O*

• O* + O2 => O3

• O3 + UV-B => O2 + O*

• pollutants act with O3 and take it out of the cycle, which leads to less oxygen in the stratosphere so that less ozone can be built up.

• UV-B can then go to our earth and can cause mutations in the DNA => Cancer

• react like a catalyst:

• CF2Cl2 => CF2Cl + Cl*

• Cl + 2 O3 => 2 ClO* + 2 O2

• 2 ClO* => ClOOCl

• ClOOCl => ClOO + Cl*

• ClOO => Cl* + O2

• Net: Cl + 2 O3 => 3 O2 + Cl*

• due to montreal protocol

1. HCFC’s

• reacts like CFC’s, breaks down faster; but still with Cl and more flammable

• Also banned for 2023

1. HFC’s

• no chlorine inside, breaks down faster

• but: super greenhouse gas!

• using ice-core data: microscopic bubbles inside of ice, shows the concentration of greenhouse gases in the past => comparison is possible

• global temperatures: are measured every year to see a trend

• climate models: predict annual global mean surface temperature

• most stable molecular shapes have the electron pair as far away from others

• only bonds with a net change in dipole absorb IR radiation

• symmetric stretches will not absorb IR radiation => N2, O2

• stretching costs more energy than bending (asymmetric, and symmetric are more energy expensive than bending mode)

• IR increases the energy content of a molecule by increasing its vibrational energy => getting hotter. To cool down the molecule emits IR radiation: long wavelength energy (visible) has been transferred into longer wavelength (IR)

• CO2 sequestration: sequest in depleted oil and gas reservoirs after removing Methane out of it, cause there is place left and methane is used for other things

• cap-and-trade system: regulation of how many greenhouse gases are allowed to be produced by specific industries.

• factors that affect the balance of eartha incoming and outgoing radiations. e.g. long-lived green-house gases

positive radiative forcings:

• greenhouse gases

• albedo (when glaciers or snow melts; deforestation) => more sun gets absorbed and IR emitted

• ozone in troposphere (also a greenhouse gas)

• warming oceans, adding more water vapour to the air (also IR reactive)

  
  

negative radiative forcings (cooling effect)

• albedo (reuse of forests and lands for crops)

• cloud formation from aerosols

• ozone in stratosphere (hinders UV-B to reach the earth)

capacity of doing work

• movement against a force: w =f*d

heat:

• energy that flows from a hotter to a colder object

• the quantity of energy dependent on mass and energy

temperature

• determines the direction of heat flow

• measurement of relative kinetic energy of particles

potential energy:

• energy due to position and composition

kinetic energy: energy due to movement

• molecules are in constant motion- even in solid state they are vibrating

• the amount of motion depends on temperature and pressure

• exothermic: energy is released (negative)

• endothermic: energy is added (positive)

net efficiency: energy produced by power plant * 100: heat from fuel

• no electric power plant can completely convert one type of energy into another, some of the energy is transferred into useless heat

• the higher the temperature of the steam, the more efficient the power plant

• Jule: 1 J is the amount of energy required to raise a 1 kg object 10 cm against the force of gravity

• calorie: 1 cal is the amount of heat required to raise the temperature of 1g of water by 1°c

• used to scrap sulfur, mercury and other pollutants from coal before burning and/ or to reduce or capture CO2

• mostly used to create electricity or for steel-making depending on type of coal (4 types)

• burn coal or react with water:

  • C + O2 => CO2

  • 2C + 2H2O => CH4 + H2O

• must be refined before using: distillation tower to separate different kinds (chain length), includes cracker to smaller long chains

• used: diesel, heating oil, plastic, chemical feedstock, pharmaceuticals, fabrics

• heat can let the large tar molecules fall apart

• catalysts help changing branching patterns => more branches = higher octan number

• straight-run gasoline has 50-55 Octan, which is too low for medium compression auto engines. It can create a lot of heat due to the pressure which can lead to fire => packing and bonding are responsible

• the measure of the resistance of gasoline to pre-ignition in a spark-ignition internal combustion engine

• percentage of iso-octane is a solution of heptan that has the same anti-knocking properties as the test gasoline

• compounds that are used to enhance the quality and efficiency of fuels: increase octane number

• tetraethyllead was used but is banned because of its toxic effects

• methyltetraethylether: has no health effects but is a major greenhouse gas

• ethanol: distillation out of plants: dubious because of so many people who are facing death because of lack of food availability

• methane, produced by organisms or from burried organic material, is the major component of natural gas

• colorless, odorless => people add H2S to give odor

• greenhouse gas

• for fuels, chemical feedstock

1. methane hydrates

• ice like rocks that contain methane

• stable under the ocean but if warmed or depressurized, will release methane to the atmosphere

1. fracking

• vertical pipe until in the are with methane => then horizontal

• high pressure fracking fluid opens networks of fractures in the shale, sand props the fractures open

• holes in the well casing allow fluid to exit and gas to enter

• gas flows into the pipe and can be used

  • but: blowouts are possible at the surface

  • methane gas can escape during the mining process and can then go into tab water

• Alcohol

  • additives, burn more clean

  • less energy needed, because of the oxygen

  • more expensive

  • still CO2 production

• Biodiesel: from vegetable oil/ animal fats

  • long chains, still produce CO2

  • dubious because of hunger problems?

  • can be blended with petroleum

• heat capacity: amount of heat required to increase temperature of material by 1°

• specific heat capacity: the amount of heat required to increase the temperature of 1g of a material by 1!

• solution: homogenous mixture, substances dissolved in another

• solute: Substance that dissolves

• solvent: dissolves the other substance

• aqueous solution: solution in which water is the solvent: universal solvent

Process of dissolving

1. solvent molecules must separate to make space for solute molecules

2. solute molecules must separate from each other

3. attraction between solvent and solute particles will allow them to move closer together and stay there

miscible: if a substance is soluble in all properties

• cation goes first and keeps its name

• anione comes next and gets “ide”

• no prefixes, only 1 possible formular

polyatomic ions:

• covalently bonded molecules that are gaining or loosing electrons

• e.g. Acetate, bicarbonate (HCO3-), Carbonate, hydroxide, hypochlorite, nitrate, nitrite, phosphate, sulfate, sulfite, ammonium

• substances that will dissociate in solutions

• h2O stabilizes ions when they dissolve

• covalent molecules remain intake when dissolved in solution => Non-electrolytes!!

1. acid rain:

• produced due to Sulfur (in coal) and Nitrite (N2 + O2 + engine heat)

• produces H+, which reacts with limestone, marble and dissolves building and statues

• acidification of lakes, seas, affects fishes, animals

• forms aerosol haze above cities: accelerated by sunlight, can cause respiratory illnesses

1. base spills

• chemical spills of salts, metals etc. into water ways

• pH change, kills animals and plants

1. ocean acidification

• CO2 reacts with water and produces H+

• H+ reacts with CO32- in water, which forces shells to dissolve to maintain co32- concentration

1. distillation: distillate the water from the salt with the use of boiling points

2. reverse osmosis: press the water out of the salt-water through a semi-permeable membrane => use in life straws to keep bacterias, virus, etc. out