Chm chapter 8 & 9

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proteins have _______ PET has __________ amides _________ esters ___________

20 different monomers, 2 different monomers, link protein monomers together, and link PET monomers together

half reaction reduction example

2H+ + 2 e- --> H2

hydrogen gas can be converted into methane

CH4 + 2 H2O + heat --> 4 H2 + CO2

which of the following pollutants are released into the environment during the production or incorrect disposal of batteries.

CO2, toxic metals, SO2

key features of a fuel cell

H2 passes through PEM and is oxidized to form two H+ ions, solid polymer electrolyte materials separate the reactants, the anode in a fuel cell simply acts as a conductor and does not participate in the oxidation reaction

whoch of the following products are formed during the electrosis of water?

H2, O2

H2 burns to form _________, CH4 burns to form _________, the energy from H2 combustion _________________, the energy from CH4 combustion ___________________.

H2O only, CO2 and H20, is higher than (124.5 kj/g), is lower than (50 kJ/g)

HDPE vs. LDPE

HDPE- stronger, more ordered structure, higher melting point, greater rigidity, opaque. LDPE- transparent, stretchy, irregular tangle of polymer chains, less strength, lower melting point

describe Group 1A metals

Li is lighter than Na; Li, Na, and K are highly reactive metals; Na and K are more abundant than Li in Earth's crust

correctly describe the role of metal hydrides for the storgae and transportation of hydrogen gas

Metal hydrides are selective and can seperate H2 from larger molecules such as O2, CO, and CO2. When placesd under high pressure the metal hydride acts like a sponge to absorb H2 molecules

common galvanic cells in order of increasing voltage, least powerful at the top.

Ni-Cd, alkaline, lead-acid, lithium-ion

advantages of PHEV's as compared to gas cars

PHEV's are less expensive to operate per mile basis, the electric energy provided by the battery decreases the direct emissions from the tailpipe

formed through addition polymerization

PP, HDPE, LDPE, PS, PVCX

discharging

Pb and Pb2 are converted into PbSO4-

recharging

PbSO4 is converted to Pb and PbO2

T/F recycling a synthetic polymer can be more energetically costly than making a new one

T

H2 is the fuel in _______ Hydrocarbon fuel cells are used in ___________________ A combustion engine produces __________________ A hydrogen fuel cell produces _______________

a hydrogen fuel cell; a combustion engine; CO, CO2, H2, and energy; H20 and electricity

n-type semiconductor

abundance of electrons, replacing Si atom with As

environmental consequences of making batteries

acid rain produced as a result of SO2 release during the metal ore refining process, lead-acid batteries may leak and release corrosive material into the evironment, and the mining of metal ores leaves mine tailings and other waster that must be cleaned up

chasllanges associated with the fabrification of photovoatic devices

although silicon is abundant, it does not occur in its elemental form, some radiant energy is lost due to reflection and absorption (to produce heat instead of electric current)

half-reaction charateristics

always occur in pairs. include electrons. electrons either show up on the left side or he right side of the half-reaction, never both.

thin-film solar cells are made from _________ silicon or nonsilicon materials such as ________

amorphous, CdTe

in both fuel cells and conventional batteries

an electrochemical reaction produces energy

lead acid ________, alkaline _________, lithium-ionide ________, nickel-metal hybrid (NiMH) __________.

automobile batteries, flashlights and small appliances, pacemakers, and hybrid vehicle batteries

hybrid electrical vehicle (HEV) is propelled by

both a conventional gasoline engine and an electric motor run on batteries

photovoltaic cells power

calculators, communication satellites, saftey lighting, and navigational bouys

thermoplastic polymer

can be melted and reshaped with heat

voltage of a battery affected by

chemical composition, number of electrochemical cells wired together

half-reaction

chemical equation that shows the electrons either lost or gained by the reactants

reduction

chemical species gains electrons. electrons show up on the left side.

oxidation

chemical species loses electrons. electrons show up on right side.

CSP

concentrating solar power ,solar collectors gater a large area of sunlight into a smaller area. The light is converted to heat ehich is used to generate electricity

solar cell/photovoltalc cell

convert light directly into electrical energy

fuel cell

converts the chemical energy of a fuel directly into elecricity without burning the fuel

sources for materials for renewable polymers

cotton, wood, starch

electrolsis

decomposition of water into H2 and O2 by passing electric curent through it

p-type semiconductor

deficit of electrons. Boron and Gallium may funstion as, replace Si with Ga

desireable for consumers about batteries

ease of recycling, affordability, long lifetime

electrodes

electrical conductors within a cell that serve as sites for chemical reactions

electrolytic cell converts

electrical energy into chemical energy

thw flow of electrons through an external circuit produces ____________, which is the flow of electrons from one region to another driven by a difference in ______ energy.

electricity; potnetial

galvanic cell

electrochemical cell that converts the energy released into a spontaneous chemical reaction into electrical energy. Several wired together makes up a true battery

describe the operation of a photoelectrochemical cell which cold potentially harness the sun's energy to produce H2?

electrons arrive at the cathode where they reduce H+ ions to H2, the cathode is made of Pt metal, dye particles at the anode absorb light causing their electrons to move to higher energy states

electrodes

energy conductors within a cell that serve as sites for chemical reactions, facilitate this electron transfer.

main disadvantage in using hydrogen as a fuel source is its

flammability

electricity

flow of electrons from one region to another that is driven by a difference in potential energy

dispersion forces

forces a result of an attraction between molecules due to a distortion in the electron cloud, uneven distribution of negative charge

standard flashlight battery

galvanic cell

energy harnessed by drilling into underground resoviours containing hot water or steam

geothermal

H2 gas can be stored using metal ___________ such as LiK, which absorb H2 molecules into the spaces within their crystal structure

hydrides

which is stronger?

intra = covalent, stronger; inter = individual molecules, weaker

cell voltage

it is a function of the chemicals used to construct the battery, higher voltages are possible by connecting cells

relationship between molecular shape and strength of dispersion forces

large surface area have more points of contact and therefore experience stronger dispersion forces

bad idea to dispose automobile batteries in landfills

leaching of chemicals from the batteries will eventually lead to groundwater contamination, toxic materials such as PbO2 will be able to enter the environment, and these metals become too widely dispersed to efficicntly collect for reuse

a hydrogen fuel cell produces energy ______ rapidly an with _____________ efficiency than the production of energy in a conventional combustion engine.

less, higher

hydrogen-rich fuels

liquid hydrogen-rich fuels include methanol and ethanol, these fuels can be used to power fuel cell vehicles, which have an on board reformer, and these fuels are converted into H2 by a device that uses heat, pressure, and catalysts to run a chemical reaction

recycled-content products

materials that would have otherwise been found in a waste stream

proteins and nylon have in common

monomers of both polymers are linked through amide linkeges, both polymers are copolymers, both polymers are formed through condensation polymerization

noncrystalline silicon absorbs photons _________ effectively than crystalline silicon, allowing the construction of ________ semiconductor layers and cheaper photovoltaic cell.

more, thinner

an addition polymer is formed when two monomers containing ____ bonds react in the presence of a ____ initiator

multiple, radical

naturally occuring source of hydrogen gas

natural gas, water, methane

two types of batteries used in hybrid electric vehicles

nickle-metal hybride batter, and lead-acid storage battery

recyclable products

not necessarily made from recycled materials but can themselves be recycled

fuel cells are a form of distributed generation since they generate electricity

on site where it is used

voltage

once the electrical circuit is complete, the voltage can be measured across the cell. voltage is the difference in electrochemical potential between the two electrodes in a galvanic cell

HDPE examples

opaque containers, toys, fencing, heavy-duty pipes

anode

oxidation takes place and is the source of electrons in the energy flow

Ina fuel cell, h2 is _________ to form 2H+ as it passes through PEM. These H+ ions combine with o2 at the cathode in a ______ half-reaction to form H2O.

oxidized, reduction

in a fuel cell, H2 is ________ to form 2H+ as it passes through PEM. These H+ ions combine with O2 at the cathode in a ____________ half-reduction to form H20.

oxidized, reduction

which methos ia the most enviromentally friendly? nuclear burning fossil fuels, photovolaic cells

photovoltaic cells

LDPE examples

plastic milk bottles, grocery bags, plastic food wrap

moleculae made of many repeating units linked together is called a ________, while the repeat units are called _________.

polymer, monomers

post consumer content

previously used industrially or individually that would have otherwise been discarded

doping

process of adding small amounts of other elements to pure silicon

a battery that employs electrochemical reactions that run both ways is _______.

rechargeable

plug-in hybrid vehicle

rechargeable batteries fro short commutes to run an electric motor and switches to combustion for longer distances.

4 r's of solid waste processing

recycle, reuse, reduce, recover

advantages of recycling

reduces waste, prevents air, water, and soil pollution; conserves natural resources

cathode

reduction takes place, receives electrons through anode through an external circuit to complete the reduction.

hybrid cars

release fewer pollutants over lifetime of car, deliever better milage in city driving, and use less gasoline

half-reaction

shows the electrons lost by reactants in a galavantic cell, the overall process occuring in a galavantic cell includes both the oxidation and the reduction reaction. A half-reaction shows the electrons gained by the reactants in a galavantic cell

installation of solar panals to power homes

solar panals are usually due south, installation on a system that rotates to follow the sun's path has a higher initial cost than a fixed solar array fot eh same size, and instillation on a system that rotates optimizes efficiency of the unit.

what from this image is a synthetic polymer

tennis ball, running shoes, and tennis racket

which of the following describe the process occurring at the anode of a galvanic cell?

the anode is the source of electrons in the current flow, and oxidation takes place at the anode

lithium ion batteries are better than alkali metal batteries because

the are very light and ideal for portable applications, they typically provide higher voltages than other batteries

describe how a simple photovoltalic cell is assembled?

the conduction of electricity is made possible by p-n junctions, a specific arrangement of p-n junctions ensures that electrons flow in a specific direction, and multiple layers of doped n and p type are placed inclose contact

correctly describe the power system of a hybrid electric vehicle (HEV)?

the electric motor draws power from the nickle-metal hydride batteries to power he vehicle at low speeds, regenerative braking is used to charge battereies during braking and deceleration, and the nicle-metal engine assists the electric motor during normal driving

What describes electricity and its production by a galvantic cell?

the flow of electrons from one region to another is driven by differences in potential energy, electricity is produced by the movement of electrons through an external circiut

which may impact the cost (both economic and environmental) of a battery?

the metals in batteries are refined from ores and this requires energy, the incorrect disposal of "dead" batteries may result in hazardous chemicals entering the enviromnent, smeltering produces CO2

two main disadvantages of the production of hydrogen from methane (CH4)?

the process requires significant energy input, CO2 is produced in addition to hydrogen

current

the rate of electron flow in a cell, measured in amperes

photovoltaic cells constructed of thin layers of alternating n and p type semiconductors are preferable to those with thicker layers because

they are more efficient due to lower internal resistence, smaller quantities of silicon are needed for device construction

alkaline batteries are called that becasue

they operate in a basic medium

one way to generate H2 for fuel cells is by the decomposition of water. The most economical way of generating the heat required to decompose water is to

use a photoelectrochemical cell

a fuel cell _________, a conventional battery, the electrodes participate in reactions _______, and the electrodes simply serve as conductors _____________.

utilizes an external source of fuel and oxidant, regulate no external source of heat or oxidant, in a conventional battery, in a fuel cell

the difference in electrochemical potential between the two electrodes of an electrochemical cell is called the ________ of the cell, measured in _________.

voltage, volts

pre consumer content

waste remaining from the manufacturing process

NOT describe the capture of wind ebnergy (both in the past and present)

wind farms can be placed at any location in the world to produce energy

typical alkaline battery exploits reactions involving

zinc, magnese


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