ENERGY Midterm

Our Earth

-approxiamately 4.6 billion years old

-3rd planet from the sun

-only known planet w/ water on surface to support life

-anaerobic life formed between 4 to 3.5 billion years ago

-oldest rocks on Earth are 4.03 billion years old

-photosynthesis started between 3.5 and 2.5 billion years ago

-atmospheric oxygen reaches 20% 1.5 billion years ago

-1st multi-cell organism 1 billion years ago

- extinction of dinasours 100 million years ago

-1st homo sapieans lived on Earth about 20 million years ago

Photosynthesis

-chloroplast in plant captures energy from sunlight and undergoes a chemical reaction to create glucose (sugar feul) and oxygen

-chemical reaction equation: CO2 + H20 + sunlight “energy” —> C6H12O6 + O2

-REQUIRES ENERGY AND CARBON DIOXIDE

Respiration/Combustion

-processs where glucose converted to usuable energy ATP

-releases NRG

-chemical reaction equation: O2 + suguar fuel —> CO2 + H2O + energy

-basically reverse of photosynthesis

Size of Earth

-Earth’s circumference = 40,000 km

-Earth’s radius = 6,400 km

-Crust = rock, 1% of Earth’s volume, thickness is 10 m

-Mandle = molten rock, semi sold, 67% of Earth’s mass, 84% of Earth’s volume

-Outer Core = iron + nickel, liquid, generates Earth’s magnetic field

-Inner Core = iron + nickel, solid, extremely hot and dense under immense pressure

Solar Wind

-constant stream of charged particles and magnetic fields from the sun, deflected by Earth’s magnetic field

Temperature Change

-Earth’s temperature has changed 30 degrees C over past few billion years

-change of 1 C = change of 1.8. F

-30 C * 1.8 F = 54 F

Composition of Earth’s Atmosphere

• Young Earth = 80% N2 and 20% CO2, intense volcanic acticity formed early atmosphere, O2 not present because photosynthesis not yet occuring

• Present Earth = 80% N2 and 20% O2 and less than 1% CO2

• Nitrogen ALWAYS present

Troposphere

-1st layer of Earth’s atmospher

-where we live and where weather occurs

-temperature goes down as altitude goes up

-extends about 10 km up

-contains water vapor and gases

Stratosphere

-2nd layer of Earth’s atmosphere

-extends between 10 km - 50 km

-contains ozone (O3) gases —> absorbs ultraviolet radiation from sun

-temp increases

Mesosphere

-3rd layer of Earth’s atmosphere

-extends 56 km - 80 km

temperature decreases as altitude increases

Thermosphere

- 4th layer of atmosphere

-outermost layer

-temperautre dramatically increases

Electromagnetic Spectrum

-sunlight is part of EM spectrum

-EM spectrum is the range of all types of EM radiation

-expressed in terms of energy, wavelength, or frequency

-unit of measurement is meter (nanos-kilos)

-HIGH energy has LOW wavelength/frequency and LOW energy has HIGH wavelength/frequency

wavelength

distance between two electromagnetic spectrum crests

frequency

number of ossilations per unit of time

Electromagnetic Spectrum Sequence

Shortest Wavelength and Highest Energy

gamma rays

X-rays

ultraviolet

visible light (400 nm to 750 nm)

• shortest is violet —— longest is red

infrared aka IR (700 nm - 1 mm)

radio waves/microwaves

TV

FM

AM

Longeest Wavelength and Lowest Energy

Radiation from Sun

-the sun gets it’s energy from process of nuclear fission

-most energy that reaches Earth’s surface comes from the sun —> solar radiation

-44% of solar radiation falls b/t visible light wavelengths

-Sun EM radiation peacks @ blue/green color

-Water, CO2, and O3 absorb radiation with certain wavelengths as it passes trhough atmosphere

Ultraviolet Light

-UVC: 100 - 200 nm — completely absorved by atmosphere

-UVB: 200-300 nm —- also causes sunburn but not as much

-UVA: 320-400 nm —- primary causes of sunburn

Infrared Light

-part of solar radiation is reflected back to space, other part is absorbed by Earth as thermal Energy —> heat re-radiated from the Earth suface

-Earth temp is colder than sun, emits longer wavelength

-Radiation from Earth is Infrared light (IR)

Greenhouse Effect

-GHG such as H2O vapor and CO2 absorb most of Earth’s emitted IR which heats the lower atmosphere —- with too much GHG in atmosphere it warms the atmosphere too much

-warmed atmosphere re-emits IR

• 10% radiates back to Earth to keep temp warm and pleasant

• 90% IR goes out

global warming

increasing concentrations of GHG increase temp. of lower atmosphere by restricting outward. passage of emitted IR radiation

Greenhouse Gases

Ranked highest to lowest concentration

-H2O vapor and clouds

-CO2

-CH4 (methane)

-O3 (ozone)

NOT A GREENHOUSE GAS: Nitrous Oxide (N2O)

CO2 Processes on Earth

-CO2 in atmosphere play role in environment because

• it’s a GHG

• carbon source for plants

• contribute to rock weathering

Carbon Cycle

process in which CO2 continually travels from atmosphere to Earth and back to atmosphere

-volcanic action increases CO2

-weathering rocks decreases CO2

-photsynthesis decreases CO2

-burnign of forests or gasolines (combustion) increases CO2

CO2 Feedback Cycle

-when Earth temp increases, CO2 increases, precipitation forms in clouds → rain + CO2 weathers rocks which decreases CO2 and decreases temperatures

Nitrogen Cycle

-process in which N2 travels through living/non-living things: atmosphere, soil, water, plants, animals and bacteria

-most abundant element in atmosphere

Nitrogen Fixation

-converts N2 into ammonia (NH3) by bacteria and other microorganisms

Nitrification

-converts ammonia to nitrite (NO2-) and nitrate (NO3-) by bacteria

Assimilation

-uptake of ammonia (NH3) , ammonium, nitrite, and nitrate by plants to be used in forming of animal/plant proteins

Amonification

-N2 from waste or dying organisms convert to ammonium and ammonia (NH3)

Denitrification

-converts nitrate (NO3-) to N2 when soil bacteria use nitrite (NO2-) for respiration instead of O2 for air

Common Prefixes

-kilo (K) = 10³ = 1,000

-Mega (M) = 10^6 = 1,000,000

-Giga (G) = 10^9 =1,000,000,000

-tera (T) = 10^12 = 1,000,000,000,000

Important Power Values

Caveman = 100 W

U.S. per capita = 10 kW

Total U.S. = 3 TW

Total World = 15 TW

Windmill = 1 MW

Nuclear Power Plant = 1 GW

Earth from Sun = 100,000 TW

Power

-rate at which NRG is transferred or converted from one object to another or one type to another

-Power = Energy/Time

-unit = Watts = 1 Joule/second

Energy

-Energy = Power x Time

-unit = Joules or kWh = 1 W x seconds

Electric Power

voltage x current

Electric Bill Calculator

1) find total Energy

2) use given rate to calculate Bill

Energy Density

-amount of energy stored in a given system, substance, or region of space per unit volume or per unite mass

-Energy/Mass or Volume

US Energy sources

Largest

Petroleum = 35%

Natural Gas = 34%

Coal = 10%

Hyrolectric

Nuclear Electric Power = 9%

Smallest

Types of Energy

• Potential Energy = energy of position

• Kinetic Energy = energy of motion of objects

• Thermal Energy = energy of motion of atoms or molecultes (temperature)

• Electrical Energy = energy of current flowing in a circuit

• Chemical Energy = energy of amotic and molecular bonds

Energy

-strength and vitality required for sustained physical or mental activity, ability to do work

Potential Energy

gravitational potential energy is energy associated with the height of an object from the ground

PE = mass x gravity x height

mass = kg

gravity = 10 m/s²

height = meters

Kinetic Energy

energy of motion for an object

KE = ½ mass x speed²

mass = kg

speed = m/s

Electrical Energy

current of energy flowing in a circuit

essential part of our life and important to US economy

total US electricity consumption in 2020 was 3.8 trillion kWh and 13x electricity use in 1950

typical power plant runs at 33% effifiency

Electrical Effieciency

Effieciency = output/input * 100

US electrical Energy sources

Largest

Natural Gas = 40.5%

Nuclear = 19.7%

Coal = 19.3%

Hydroelectric = 7%

Oil = 0.4%

Smallest

61% from fossil fuels

History of electricity

• ancient societies knew of electric charge from eels and rubbing amber caused materials to stick because of electrostatic forces

• Ben Franklin experiments in 1752 w/ electricity & lightning

• thought positive charges flowed but WRONG

Electric Charge

• fundamental physical property that causes objects to feel an attractive or repulsive force

• two types positive or negative

• protons are positive

• electrons are negative

  • neutrons are neutral → particles that flow to create electric current

Static Electricity

• if 2 different marterials touch then electrons move from one material to another and become oppositely charged therefore ATTRACT eachother

• a negative to a positive

Electrical Current

motion of electrions

(I)

unit = Amperes (A)

Electrical Voltage

difference in charge causing current

(V)

unit = volt (V)

positive and negative sides of battery

Voltage = current (I) x Resister (R)

Electrical Power

Electrical Power = electrical current (I) x Electrical voltage (V)

measured in Watts

Resister Circuit

(R)

resisters control electron speed to reduce fire

increased current increases voltage BUT increased resister decreases current

Electrical Power numbers

US Household = 120 V (240)

Europe Household = 240 V

Circuit breaker = 15 - 40 Amps

Transformers

-transmission lines carry high voltage > 10 kV

-step up or down voltage on a transmission line allowing for safe lower voltages to be used in households

-use a high voltage to deliver power suffiently at high rate without high current

Capacity

miximum output of electricity that a generator produces under ideal conditions

measured in MW or KW

Electricity Generation

amount of electricity that is produced over a specific period of time

measured in kWh, MWh, or TWh

Electricty generation = power x time

Temperature

• thermal energy of an object

• describes average kinetic energy of molecules in matter

• cold is slow molecular movement, hot is fast molecular movement

Heat

• flow/transfer of thermal energy between objects with different temperatures

• symbol Q

• unit = Joule or kcalorie

Kelvin, Celsius, and Fahrenheit

Water Boils: 373 K 100 C 212 F

Water Freezes: 273 K 0 C 32 F

Absolute zero (where all molecular motion ceases): 0 K -273 C -460 F

Kelvin = Celsius + 273

Fahrenheir = 9/5*Celsius + 32

Conduction

• transfer of energy as heat from one substance or particle to another through direct contact

• need a solid medium & physical contact

• ex: kettle on stove burn hand when touch warm metal

Convection

• transfer of energy as heat by the movement of a liquid or gas

• follows a circular patter

• ex: pot of heating water → warm air rises and cold air sinks

Radiation

• transfer of energy by electromagnetic waves

• hotter objects radiate more energy

• ex: heat from sun or from camp fire

R-Value

• value of a material used to measure how well a specific type of material can resist heat

• depends on type and thickness → relationship between thickness & R-value is proportional

• higher R-value = more effective at preventing heat transfer

• R-Value = thickness (inches) x R-value per inch

  • add everything up to get total R-value

Phases of Water

Ice: molecules vibrate in a cystal structure, bond is strong, melts at 0 C, less dense than water

Liquid: molecules move but still attracted to eachother, evaporates at 100 C

Gas/Vapor: molecules are fast and far apart

Specific Heat (Heat capacity)

• how much heat energy is required to increase the temperature of 1 kg of substance by 1 C

• Q = m*c*change in temp

  • Q - kcal

  • m - kg

  • c - (specific heat) kcal/kgC

  • t - celsius

• C (liquid water) = 1

• C (ice/vapor) = 0.5

Phase Changes in Water

• during phase changes temp remains constant until enough energy has been added to complete a phase change

Most Energy

liquid to vapor (evaporation) = 540 kcal

• heating liquid = 100 kcal

ice to liquid (melting) = 80 kcal

Least Energy

Latent Heat

• L

• how much heat NRG is required for a phase change (melting/evaporating)

• Q = m x L

  • q = kcal

  • m = kg

  • L = kcal/kg

• L (melting) = 80

• L (evaporating) = 540

Evaporation

• liquid to vapor

• thermal energy provided

• endothermic reaction

• creates humid air

Condensation

• vapor to liquid

• thermal energy released

• exothermic reaction

• creates liquid droplets

Water Cycle

-NRG required to evaporate 1 kg of H2O is EQUAL to NRG released when 1 kg vapor condenses into liquid

Hurricanes

• need warm ocean water & warm humid wind over water

• warm ocean water > 80 F stores NRG

• low pressure core creates circulation of moist air

• have a spiral/rotating shape due to Coriolis force (Earth’s rotation)

Laws of Thermodynamics

1) Energy is conserved: neither created nor destroyed BUT can change forms

2) Disorder or entropy increases for a spontaneous process

Heat Engine

-extracts mechanical/electrical NRG when material flows between hot & cold reservoirs

• e = 1 - T_cold / T_hot

• _{e = maximum efficiency}

• _{T in Kelvins}

• _{Output NRG = efficiency x Input NRG → measured in MJ}

Order of Car Engine Energy

1) Chemical NRG - fuel

2) Thermal NRG - engine

3) Mechanical/Kinetic NRG - car moving

NRG losses for an Automobile

highest

thermodynamic losses of a heat engine

engine friction

air resistance/breaking/tire resistance

lowest

Fossil Fuels

-made by geological processes acting on ancient dead organisms buried hundreds of millions of years ago

-considered non-renewable energy source because cannot be produced @ rate they are consumed

-NRG initially from from sun then photosynthesis done by dead biomasses

-ex: coal, heating oil (kerosene), natural gases → 100% fossil fuels

-refered to as hydrocarbon resouces b/c made from mainly H & C BUT also O,N. S, etc.

Combustion

-burning of feul to produce thermal energy → burning coal, running internal combustion engine, respiration of a person

-NRG required to initially break chemical bonds in hydrocarbon molecules

-themal NRG released during formation of new molecules such as CO2, H2O, and pollutants NO & SO → used as heat or converted to mechanical NRG like in heat engines

Combustion Process

Feul + O2 → CO2 + H2O + Energy

breaking bonds forming bonds

requires NRG releases more NRG

Chemical NRG

• NRG due to chemical reactions when bonds are broken and formed

• conservation NRG = more NRG releases when stable bond forms b/c requires same amount of NRG to break stable bond again

  • molecules always more stable & have lower Potential Energy

Total Energy Change

-in a chemical reaction is a balance b/t the NRG changes when bonds are broken & formed

endothermic = NRG required

exothermic = NRG released

Energy Density

-amount of NRG that can be stored in a given system, substance, or region of space

-expressed in 2 ways

• Volumetric Energy Density = how much NRG a system contains in comparison to its volume → Wh/L or MJ/L (L = liters)

• Gravimetric Energy Density = how much NRG in a system compared to its mass → Wh/kg or MJ/kg

Molecules Energy Content Ranking

High Energy Content (high H:C ratio)

CH4 (methane - natural gas)

C8H18 (octane - gasoline)

C16H40O8N4S2P (coal)

CH3Ch2OH (ethanol - biofuel)

CO2 (carbon dioxide - GHG)

Low Energy content (low H:C ratio)

Coal

• in acidic swamp environment without oxygen-rich air plants decay and turn into peat

• sugar + little O2 → peat + H2O

• after millions of years of heat and pressure peat is converted to coal

• coal contains different impurities depending on its location

Order of Coals Formed

1) Lignite Coal = high moisture content, low NRG density, used as electricity in early generations

2) Sub-Bituminious Coal = soft & black with higher NRG density than lignite

3) Bituminious coal = soft & shiny, high NRG density used in electricity and steel making

4) Anthracite = very shiny & black, hard, high carbon content and high NRG densisty

• as carbon content increases NRG content increases

• as oxygen content increases NRG content decreases

Coal Power Plant NRG Process

1) coal - chemical

2) furnace - thermal

3) turbines - mechanical

4) electrical

Oil and Natural Gas

• ancient microorganisms died & settled at bottom of warm shallow oceans

• during decay without oxygen gradually turn into oil or gas

• dead algae → kerogen (oil shales) → oil → natural gas

• oil/gas rises after forming because has lower density than water

Edwin Drake

• father of petroleum industry

• first oil well drilled in US in 1859 in Titusville, PA

Components of Oil

• oil refineries seperate crude oil into various usuable petroleum products

• gasoline, petrochemical feedstock, jet feul, heating oil, asphalt, lub oil, distillates diesel fuel

• about half an oil barrel is gasoline

• asphalt has heaviest hydrocarbon molecules

Fossil Feul Molecules

CH4 = methane (natural gas)

C8H18 = octane (gasoline)

C12H26 = disel fuel

C35H72 = asphalt

• more carbons in a hydrocarbon molecule makes molecule heavier

Fractional Distillation Process

• different hydrocarbon products aka fractions are separated and condense at different temperatures

• lighter molecules have low boiling point rise to the top

• heavier molecules have high boiling points and stay at bottom

• distillation tower is hottest at the bottom

Highest boiling points

black

yellow

clear

Lowest boiling points

Quad

• 10¹⁸ MJ or 10¹⁵ BTU

• unit of energy

• World Reserves in Quads

  • coal = 25,000 q

  • conventional oil = 6,000 q (about 40 years left)

  • Natural gas = 6,000 q

Oil (tar) Sand

• more economical than conventional oil & more reserves

• mixture of sand, H2O, Bitumen, and clay

• Canada has largest oil sand reserves

• Viscosity of Bitumen = 500,000 close to peanut butter

Oil Sand Formation

• takes million years to form

• obtained by heating or pyrolyzing sands @ high temps can’t direcelty pump from gound

• 2 tons mined oil sands = 1 barrel synthetic crude oil

1) Surface Mining (SM) = recycle about 80% of water used BUT uses more water

2) Steam Assisted Gravity Drainage (SAGD( = about 90% of water use is recycled

Hubert’s Peak for Oil Production

• gas was cheapest in 1998

• gas only 9 cents higher in 2019 than 1929

• Hubert’s Curve = rate of oil production in given region over time follows bell-shaped curve

• Hubert’s peak = peak point where production rate is highest & half of oil reserve has been exhausted

  • before peak more oil and less expensive to extract

  • after peak reserves are more expensive to extract and less oil

• US oil production peaked in 1970

Litmus Test

• litmus made from lichens in the Netherlands made available since 1600s

• acidity of chemicals classified using this test

• acids turn pink

• bases turn blue

pH Scale

• measures concentration of Hydrogen Ions in a solution

• acid < 7

• neutral = 7

• bases > 7

• as pH increases acid decreases

• as pH decreases acid increases

• Acidity = 1/10^{pH scale}

• many foods are acidic and many soaps are basic

• WATER AND SALT ARE NEUTRAL

• normal rain = 5.6

• acid rain = 4.3

Acid Rain/Smog

• occurs when Sulfur Oxides (SO_x) from burning fossil fuels in power stations and Nitrogen Oxides (NO_x) from burning oil in motor vehicles react with water droplets in the atmosphere

• make Sulfuric Acid (H2SO4) and Nitric Acid (HNO3)

• more acidic rain in Eastern US

• acid rain affects vegetation, fresh water ecosystems, soil, animals, and nature & man-made structures

  • damages statue surfaces, removes minerals/nutrients from soil & adds aluminium

Acid Rain Program

• 1995

• requires reduction of SO_x and NO_x from power sector

• been succesful

• delivered annual SO2 reductions of over 93% and NOx emission reductions over 87%

Great Smog of London

• December 1952

• temperature inversion trapped cold air below warm air & caused acid fog, main cause was burning coal

• killed 4,000-12,000 more people than usual over 6 months

• Clean Air Act passed in 1956 in England

Winter Smog in Donord, PA

• 1948

• temperature inversion caused acid fog lasted for a week

• during that time killed 20 people and elevated death rates for 1 year after

• caused lifetime health problems

• Clean Air Act passed in 1970 in US