Zajęcia dokształcające z języka angielskiego w chemii nr

Zajęcia dokształcające z języka angielskiego w chemii nr. 6
(opracował - P. Przybylski)
Kontynuacja zajęć mających na celu wprowadzenie podstawowego słownictwa z zakresu chemii fizycznej szczególnie definicji podstawowych wielkości z zakresu chemii fizycznej (poruszane zagadnienia i przykłady
tekstów zostały podane poniżej) – część druga.
ELECTROCHEMICAL CELLS
Przykład tekstu publikacji: Cathode materials for
rechargeable lithium batteries
GLOSSARY:
Electrochemical cells – ogniwa elektrochemiczne
electrodes – elektrody
metallic conductor – przewodnik metaliczny
electrolyte – elektrolit
electrode compartment – komora elektrody
to share – dzielić
inert metal – metal inertny
catalyst – katalizator
salt bridge – mostek solny (klucz elektrolityczny)
concentrated – stężony
jelly – galaretka
galvanic cell – ogniwo galwaniczne
electricity – elektryczność
spontaneous reaction – reakcja spontaniczna
external source of current – zewnętrzne źródło prądu
half-reactions – reakcje połówkowe (na elektrodach)
oxidation – utlenienie
reduction – redukcja
species – cząstki
redox reaction – reakcja redoks
electron transfer – przeniesienie elektronu
oxidation number – stopień utlenienia
reducing agent – czynnik redukujący
reductant – reduktor
oxidizing agent – czynnik utleniający
oxidant – utleniacz
express – wyrażać
conceptual – pojęciowy
difference – różnica
separated – rozdzielony
release - uwolnić
proceed – postępować, zachodzić (o reakcji chemicznej)
anode – anoda
cathode – katoda
circuit – obwód
higher potential – wyższy potencjał
positive charge – dodatni ładunek
negative charge – ujemny ładunek
to be a supply with … – być zaopatrywanym w …
necessary – konieczny, niezbędny
immerse – zanurzać
Daniell cell – ogniwo Daniella
electrolyte concentration cell – ogniwo elektrolityczne stężeniowe
gas electrodes – elektrody gazowe
pressure – ciśnienie
amalgam – amalgamat
source of potential – źródło potencjału
interface – obszar wzajemnego oddziaływania
diffuse – dyfundują
dilute solution – roztwór rozcieńczony
bulkier – większe, o większej objętości
at the same rate – z taką samą szybkością
cell diagram – schemat zapisu ogniwa
cell reaction – reakcja ogniwa
assumption – założenie
substract – odejmować
cell potential – potencjał ogniwa
chemical equilibrium – równowaga chemiczna
accomplish – realizować
volt – Volt
amount - ilość
electrical work – praca elektryczna
measurement – pomiar
reversibly – odwracalnie
Gibbs energy – energia Gibbsa
ensure – zapewnić
constant composition – stały skład (chem.)
balanced – zrównoważony
to be poised for change – być gotowym na zmianę
electromotive force /electromotance/ – siła elektromotoryczna
Faraday constant – stała Faradaya
Przykład fragmentu tekstu z czasopisma “Electrochemistry Communications” authored by Sun et al. 10 (2008)
1819-1822.
Nano-wire networks of sulfur–polypyrrole composite cathode materials for rechargeable lithium batteries.
Introduction
The development of high energy density rechargeable batteries is of great importance due to the increasing demand
of high energy for portable electronic and electrical applications. Elemental sulfur is very attractive as a cathode
material for high specific energy rechargeable lithium cells based on the lithium–sulfur redox couple would yield a
theoretical specific capacity of 1675 mA h g-1 and theoretical specific energy 2600 Wh kg-1 on the assumption of the
complete reaction of lithium with sulfur to Li2S [1]. Furthermore, sulfur shows other advantages as cathode materials
due to its abundance, low cost and environmental friendliness [2]. In spite of these advantages, the insulating
nature of sulfur prevents full discharge of a Li/S battery with a 100% sulfur positive electrode at room
temperature. Therefore, the cathode materials must be well combined with electrical and ionic conducting agent.
Another problem putting off the application of sulfur as a cathode material in rechargeable lithium battery is its rapid
capacity fading during cycling. The fading arrives from the fact that several lithium polysulfides, formed during
discharge process, are dissolved in the liquid electrolytes. The use of absorbing agent is an approach to relieve the
dissolving of polysulfides such as aluminium oxide, silicates, and vanadium oxides [3]. However, the effectiveness
for improving cycle performance is unsatisfied due to their larger particle size and low specific surface area.
Mesoporous carbon, active carbon, multiwalled carbon have better performance as absorbing agent in Li/S battery
[4–6] due to their high porous structure and large surface area. Therefore, we target our work on finding a new
absorbing agent with large surface area. PPy used to be studied as an additive to improve the performance of cathode
and anode materials in lithium-ion batteries and lithium batteries [7–10]. Recently, a novel PPy was prepared through
surfactant mediated approach which existed as nano-wire networks [11]. In this study, we used this PPy as a novel
absorbing agent and investigated the effectiveness to improve electrochemical performance in lithium–sulfur
batteries.
Experimental
Preparation of nano-wire networks of polypyrrole
Polypyrrole nano-wire was prepared by a chemical polymerization method with cationic alkyltrimethylammonium
surfactants (CTAB) as soft templates. Magnetically stirred solution of cooled (-2 °C) 0.2 M CTAB in 1.0 M HCl
(200 ml) immediately turned very viscous when 0.26 M pyrrole were added. After vigorous stirring for 10 min, a
solution of cooled (-2 °C) 0.06 M (NH4)2S2O8 in 1.0 M HCl (200 ml), was added all at once. The reaction mixture
was stirred for 3 h at constant temperature (-2 °C). The resulting black precipitate of doped polypyrrole was
suction filter in air and washed with copious amounts of deionized water and acetone. Suction filtration yielded a
film on the surface of the filter. After dried in vacuum at temperatures of 80 °C for 12 h, the film was grinded into
powder [11].
Electrochemical measurements
The sulfur–polypyrrole (S–PPy) cathode slurry was made by mixing 60% composite material, containing about 40%
sulfur and 20% PPy, with 30% acetylene black (AB) and 10% LA132 in propyl alcohol aqueous solvent to form a
homogeneous slurry. Sulfur cathode slurry containing 60% sulfur powder, 30% AB and 10% LA132 was also
prepared in the same way as described previously to compare with S–PPy composite. The slurries were spread onto
aluminum foil substrates. The coated electrodes were dried in a vacuum oven at 55 °C for 24 h. Subsequently, the
electrodes were cut to a 1 cm × 1 cm size. CR 2025 coin-type cells were assembled in an Ar-filled glove box
(Mbraun, Unilab, Germany). The electrolyte used was 1 MLiCF3SO3 in a solvent of DOL:DME (1:1). The cells were
galvanostatically discharged and charged on a LAND electrochemical in the range of 1.5 V–3.0 V. The chargeable
current density was 0.4 mA cm-2 and the dischargeable current density was 0.1 mA cm-2. Cyclic voltammetry
measurements were performed between 1.5 V–3.0 V at a scanning rate of 0.1 mV s-1.
GLOSSARY:
Nano-wire networks- sieci nanorurek
sulfur–polypyrrole composite – kompozyt siarkowo-polipirolowy
rechargeable lithium batteries – baterie akumulatorowe litowe
high energy density – wysokiej gęstości energetycznej (ilość energii użytk. w jednostce objętości)
portable – przenośny
cathode material – materiał katodowy
lithium–sulfur redox couple – para redoks lit-siarka
capacity – pojemność
advantages – korzyści, zalety
abundance – abundancja, obfitość
environmental friendliness – przyjazność środowisku, naturze
insulate – izolować
full discharge – całkowite rozładowanie
at room temperature – w temperaturze pokojowej
combined – połączony
rapid – gwałtowny, bardzo szybki
fad – przelotna, chwilowa
polysulfides - polisulfidy
liquid electrolytes – ciekłe elektrolity
aluminium oxide – tlenek glinu
silicates – krzemiany
vanadium oxides – tlenki vanadu
particle size – rozmiar cząstek
mesoporous carbon – mezoporowaty węgiel
active carbon – węgiel aktywny
porous structure – struktura porowata
surface – powierzchnia
surfactant – surfaktant
absorbing agent – środek absorbujący
chemical polymerization – chemiczna polimeryzacja
soft templates – miękka matryca
Magnetically stirred – magnetycznie mieszane
viscous – lepki
at constant temperature – przy stałej temperaturze
black precipitate – czarny osad
suction filter - filtr próżniowy
acetone – aceton
dried – suszony
grinded – rozkruszony
powder – proszek
slurry – zawiesina
propyl alcohol – alcohol propylowy
homogeneous – homogeniczny
coated electrodes – pokryte elektrody
galvanostatically discharged – galwanostatycznie rozładowane
the chargeable current density – gęstość prądu ładowania
dischargeable current density – gęstość prądu rozładowania
Cyclic voltammetry – cykliczna woltametria
scanning rate – szybkość skanowania
Druga część zajęć ma na celu wprowadzenie podstawowego słownictwa z zakresu chemii koordynacyjnej i katalizy.
COORDINATION CHEMISTRY
CATALYSIS
Wybrane fragmenty z książki p.t. “Comprehensive Coordination Chemistry” ed. G. Wilkinson,. R.D. Gillard and
J.A. McCleverty, Pergamon Press, Oxford, 1987.
GLOSSARY:
coordination compound – związek koordynacyjny
coordination number – liczba koordynacyjna
coordination geometry – geometria koordynacji
uni-, bi-, poly-dentate ligands – ligandy jedno-, dwu- i wielokleszczowe
complex compounds – związki kompleksowe
complexes – kompleksy
transition metal salt – sól metalu przejściowego
oxidation state – stopień utlenienia
primary/ secondary valence – wartościowość pierwszorzędowa (główna)/ drugorzędowa
metal ion – jon metalu
bonded - związany
counterion – przeciwjon
orientation in space – zorientowanie w przestrzeni
metal-bound groups – grupy wiążące metal
geometric structure – struktura geometryczna
Lewis acid – kwas Lewisa
Broensted base – zasada Broensteda
electron pair acceptor – akceptor pary elektronowej
proton acceptor – akceptor protonu
ligands – ligandy
macromolecules – makromolekuły
to donate an electron pair – oddawać parę elektronową
organometallic compounds – związki metaloorganiczne
single point of attachment – jeden punkt przyłączenia
several – kilka
donor atoms – atomy donorowe
chelate complex – kompleks chelatowy
stable – stabilny
variety – różnorodność
carbon donor atom – donorowy atom węgla
chelate ring – pierścień chelatowy
four-membered chelate ring – czteroczłonowy pierścień chelatowy
cyclic compounds – związki cykliczne
macrocyclic - makrocykliczny
bicyclic proligands – bicykliczne proligandy
to encapsulate a metal ion – zamknąć szczelnie jon metalu
cryptand – kryptand
bridging arrangement – mostkowe ułożenie
f-block elements – pierwiastki bloku f
structural isomers – izomery strukturalne
more favourable energetically – bardziej energetycznie uprzywilejowany
regular geometry – regularna geometria
distortion – zniekształcenie, odkształcenie
homo/heteroleptic – homo/heteroleptyczny
bulky ligand – duży, objętościowy ligand
prevent – zapobiegać
linear – liniowy
amide ligand – ligand amidowy
planar structure – struktura płaska
pyramidal – piramidalny
square planar – płasko-kwadratowe
tetrahedral – tetraedryczne
trigonal plane – trygonalna płaska
trigonal bipyramidal – bipiramida trygonalna
square pyramidal – piramida kwadratowa
octahedral – oktaedryczny
ligand-ligand interaction – odziaływanie ligand-ligand
trigonal prismatic – pryzmat trygonalny
tetragonal distortion – odkształcenie tetragonalne
trigonal distortion – odkształcenie trygonalne
fourfold rotation axis – oś czterokrotna obrotu
dodecahedral – dodekaedryczny
square antiprismatic – antypryzmat kwadratowy
icosahedral – ikozaedryczny
geometric isomerism – izomeria geometryczna
optical isomerism – izomeria optyczna
adjacent – przyległy, sąsiedni
facial - facjalny
meridional - południkowy
Fragmenty tekstu “Types of catalytic reactions”, http://www.chemguide.co.uk/physical/catalysis/introduction.html
Types of catalytic reactions
Catalysts can be divided into two main types - heterogeneous and homogeneous. In a heterogeneous reaction, the
catalyst is in a different phase from the reactants. In a homogeneous reaction, the catalyst is in the same phase as the
reactants.
What is a phase?
If you look at a mixture and can see a boundary between two of the components, those substances are in different
phases. A mixture containing a solid and a liquid consists of two phases. A mixture of various chemicals in a single
solution consists of only one phase, because you can't see any boundary between them.
You might wonder why phase differs from the term physical state (solid, liquid or gas). It includes solids, liquids and
gases, but is actually a bit more general. It can also apply to two liquids (oil and water, for example) which don't
dissolve in each other. You could see the boundary between the two liquids.
If you want to be fussy about things, the diagrams actually show more phases than are labelled. Each, for example,
also has the glass beaker as a solid phase. All probably have a gas above the liquid - that's another phase. We don't
count these extra phases because they aren't a part of the reaction.
Heterogeneous catalysis
This involves the use of a catalyst in a different phase from the reactants. Typical examples involve a solid catalyst
with the reactants as either liquids or gases.
How the heterogeneous catalyst works (in general terms)
Most examples of heterogeneous catalysis go through the same stages:
One or more of the reactants are adsorbed on to the surface of the catalyst at active sites.
Adsorption is where something sticks to a surface. It isn't the same as absorption where one substance is taken up
within the structure of another. Be careful! An active site is a part of the surface which is particularly good at
adsorbing things and helping them to react. There is some sort of interaction between the surface of the catalyst and
the reactant molecules which makes them more reactive. This might involve an actual reaction with the surface, or
some weakening of the bonds in the attached molecules. The reaction happens.
At this stage, both of the reactant molecules might be attached to the surface, or one might be attached and hit by the
other one moving freely in the gas or liquid.
The product molecules are desorbed. Desorption simply means that the product molecules break away. This leaves
the active site available for a new set of molecules to attach to and react. A good catalyst needs to adsorb the reactant
molecules strongly enough for them to react, but not so strongly that the product molecules stick more or less
permanently to the surface. Silver, for example, isn't a good catalyst because it doesn't form strong enough
attachments with reactant molecules. Tungsten, on the other hand, isn't a good catalyst because it adsorbs too
strongly. Metals like platinum and nickel make good catalysts because they adsorb strongly enough to hold and
activate the reactants, but not so strongly that the products can't break away.
Examples of heterogeneous catalysis
The hydrogenation of a carbon-carbon double bond
The simplest example of this is the reaction between ethene and hydrogen in the presence of a nickel catalyst.
In practice, this is a pointless reaction, because you are converting the extremely useful ethene into the relatively
useless ethane. However, the same reaction will happen with any compound containing a carbon-carbon double bond.
One important industrial use is in the hydrogenation of vegetable oils to make margarine, which also involves
reacting a carbon-carbon double bond in the vegetable oil with hydrogen in the presence of a nickel catalyst. Ethene
molecules are adsorbed on the surface of the nickel. The double bond between the carbon atoms breaks and the
electrons are used to bond it to the nickel surface.
Hydrogen molecules are also adsorbed on to the surface of the nickel. When this happens, the hydrogen molecules
are broken into atoms. These can move around on the surface of the nickel.
If a hydrogen atom diffuses close to one of the bonded carbons, the bond between the carbon and the nickel is
replaced by one between the carbon and hydrogen.
That end of the original ethene now breaks free of the surface, and eventually the same thing will happen at the other
end.
As before, one of the hydrogen atoms forms a bond with the carbon, and that end also breaks free. There is now space
on the surface of the nickel for new reactant molecules to go through the whole process again.
Note: Several metals, including nickel, have the ability to absorb hydrogen into their structure as well as adsorb it on to the surface. In these
cases, the hydrogen molecules are also converted into atoms which can diffuse through the metal structure.
This happens with nickel if the hydrogen is under high pressures, but I haven't been able to find any information about whether it is also
absorbed under the lower pressures usually used for these hydrogenation reactions. I have therefore stuck with the usual explanation in terms
of adsorption.
Catalytic converters
Catalytic converters change poisonous molecules like carbon monoxide and various nitrogen oxides in car exhausts
into more harmless molecules like carbon dioxide and nitrogen. They use expensive metals like platinum, palladium
and rhodium as the heterogeneous catalyst. The metals are deposited as thin layers onto a ceramic honeycomb. This
maximises the surface area and keeps the amount of metal used to a minimum.
Taking the reaction between carbon monoxide and nitrogen monoxide as typical:
In the same sort of way as the previous example, the carbon monoxide and nitrogen monoxide will be adsorbed on
the surface of the catalyst, where they react. The carbon dioxide and nitrogen are then desorbed.
The use of vanadium(V) oxide in the Contact Process
During the Contact Process for manufacturing sulphuric acid, sulphur dioxide has to be converted into sulphur
trioxide. This is done by passing sulphur dioxide and oxygen over a solid vanadium(V) oxide catalyst.
This example is slightly different from the previous ones because the gases actually react with the surface of the
catalyst, temporarily changing it. It is a good example of the ability of transition metals and their compounds to act as
catalysts because of their ability to change their oxidation state. The sulphur dioxide is oxidised to sulphur trioxide by
the vanadium(V) oxide. In the process, the vanadium(V) oxide is reduced to vanadium(IV) oxide.
The vanadium(IV) oxide is then re-oxidised by the oxygen.
This is a good example of the way that a catalyst can be changed during the course of a reaction. At the end of the
reaction, though, it will be chemically the same as it started.
Homogeneous catalysis
This has the catalyst in the same phase as the reactants. Typically everything will be present as a gas or contained in a
single liquid phase. The examples contain one of each of these . . .
Examples of homogeneous catalysis
The reaction between persulphate ions and iodide ions
This is a solution reaction that you may well only meet in the context of catalysis, but it is a lovely example!
Persulphate ions (peroxodisulphate ions), S2O82-, are very powerful oxidising agents. Iodide ions are very easily
oxidised to iodine. And yet the reaction between them in solution in water is very slow.
If you look at the equation, it is easy to see why that is:
The reaction needs a collision between two negative ions. Repulsion is going to get seriously in the way of that! The
catalysed reaction avoids that problem completely. The catalyst can be either iron(II) or iron(III) ions which are
added to the same solution. This is another good example of the use of transition metal compounds as catalysts
because of their ability to change oxidation state. For the sake of argument, we'll take the catalyst to be iron(II) ions.
As you will see shortly, it doesn't actually matter whether you use iron(II) or iron(III) ions. The persulphate ions
oxidise the iron(II) ions to iron(III) ions. In the process the persulphate ions are reduced to sulphate ions.
The iron(III) ions are strong enough oxidising agents to oxidise iodide ions to iodine. In the process, they are reduced
back to iron(II) ions again.
Both of these individual stages in the overall reaction involve collision between positive and negative ions. This will
be much more likely to be successful than collision between two negative ions in the uncatalysed reaction. What
happens if you use iron(III) ions as the catalyst instead of iron(II) ions? The reactions simply happen in a different
order.
The destruction of atmospheric ozone
This is a good example of homogeneous catalysis where everything is present as a gas. Ozone, O3, is constantly being
formed and broken up again in the high atmosphere by the action of ultraviolet light. Ordinary oxygen molecules
absorb ultraviolet light and break into individual oxygen atoms. These have unpaired electrons, and are known as free
radicals. They are very reactive.
The oxygen radicals can then combine with ordinary oxygen molecules to make ozone.
Ozone can also be split up again into ordinary oxygen and an oxygen radical by absorbing ultraviolet light.
This formation and breaking up of ozone is going on all the time. Taken together, these reactions stop a lot of harmful
ultraviolet radiation penetrating the atmosphere to reach the surface of the Earth. The catalytic reaction we are
interested in destroys the ozone and so stops it absorbing UV in this way. Chlorofluorocarbons (CFCs) like CF2Cl2,
for example, were used extensively in aerosols and as refrigerants. Their slow breakdown in the atmosphere produces
chlorine atoms - chlorine free radicals. These catalyse the destruction of the ozone. This happens in two stages. In the
first, the ozone is broken up and a new free radical is produced.
The chlorine radical catalyst is regenerated by a second reaction. This can happen in two ways depending on whether
the ClO radical hits an ozone molecule or an oxygen radical. If it hits an oxygen radical (produced from one of the
reactions we've looked at previously):
Or if it hits an ozone molecule:
Because the chlorine radical keeps on being regenerated, each one can destroy thousands of ozone molecules.
Autocatalysis
The oxidation of ethanedioic acid by manganate(VII) ions
In autocatalysis, the reaction is catalysed by one of its products. One of the simplest examples of this is in the
oxidation of a solution of ethanedioic acid (oxalic acid) by an acidified solution of potassium manganate(VII)
(potassium permanganate).
The reaction is very slow at room temperature. It is used as a titration to find the concentration of potassium
manganate(VII) solution and is usually carried out at a temperature of about 60°C. Even so, it is quite slow to start
with. The reaction is catalysed by manganese(II) ions. There obviously aren't any of those present before the reaction
starts, and so it starts off extremely slowly at room temperature. However, if you look at the equation, you will find
manganese(II) ions amongst the products. More and more catalyst is produced as the reaction proceeds and so the
reaction speeds up. You can measure this effect by plotting the concentration of one of the reactants as time goes on.
You get a graph quite unlike the normal rate curve for a reaction.
Most reactions give a rate curve which looks like this:
Concentrations are high at the beginning and so the reaction is fast - shown by a rapid fall in the reactant
concentration. As things get used up, the reaction slows down and eventually stops as one or more of the reactants are
completely used up.
An example of autocatalysis gives a curve like this:
You can see the slow (uncatalysed) reaction at the beginning. As catalyst begins to be formed in the mixture, the
reaction speeds up - getting faster and faster as more and more catalyst is formed. Eventually, of course, the rate falls
again as things get used up.
Warning!
Don't assume that a rate curve which looks like this necessarily shows an example of autocatalysis. There are other
effects which might produce a similar graph. For example, if the reaction involved a solid reacting with a liquid, there
might be some sort of surface coating on the solid which the liquid has to penetrate before the expected reaction can
happen. A more common possibility is that you have a strongly exothermic reaction and aren't controlling the
temperature properly. The heat evolved during the reaction speeds the reaction up.
GLOSSARY:
catalytic reaction – reakcja katalityczna
catalyst – katalizator
divide – dzielić
heterogeneous – heterogeniczny
homogeneous – homogeniczny
reactants – reagenty
solid/liquid/gas phase – faza stała/ciekła/gazowa
mixture – mieszanina
component - składnik
solution – roztwór
oil – oliwa, olej
fussy – wybredny, grymaśny
glass beaker – szklana zlewka
adsorbed – zaadsorbowany
active site – miejsce aktywne
absorption – absorpcja
to react – reagować
surface – powierzchnia
weakening of the bonds – osłabienie wiązań
desorption – desorpcja
silver – srebro
tungsten - wolfram
platinum – platyna
nickel – nikiel
pointless reaction – bezcelowa reakcja
industrial – przemysłowy
vegetable oil – olej roślinny
break free - uwolnić
under high pressure – pod wysokim ciśnieniem
poisonous – trujący
carbon monoxide – tlenek węgla
nitrogen oxides – tlenki azotu
carbon dioxide – dwutlenek węgla
nitrogen – azot
palladium – pallad
rhodium – rod
are deposited – są osadzone
thin layer – cienka warstwa
ceramic honeycomb – ceramiczny plaster miodu
to maximize the surface – maksymalizować powierzchnię
vanadium (V) oxide – tlenek wanadu (V)
Contact Process – metoda kontaktowa (produkcji H2SO4)
sulphuric acid – kwas siarkowy
sulphur dioxide – dwutlenek siarki
temporarily – tymczasowo
change the oxidation state – zmiana stopnia utlenienia
oxidised – utleniony
reduced – zredukowany
persulphate /peroxodisulphate ion – jon nadsiarczanowy/nadtlenodwusiarczanowy
oxidizing agent – środek utleniający
iodide ion – jon jodkowy
iodine – jod
equation – równanie
iron – żelazo
suplphate ions – jony siarczanowe
ozone – ozon
in the high atmosphere – wyższych partiach atmosfery
ultraviolet light – światło ultrafioletowe
free radicals – wolne rodniki
reactive – reaktywny
aerosol – aerozol
refrigerant – czynnik chłodniczy
in two stages – w dwóch etapach
chlorine atoms – atomy chloru
chlorine free radicals – wolne rodniki chlorowe
autocatalysis – autokataliza
oxalic acid – kwas szczawiowy
potassium permanganate – nadmanganian potasu
speeds up – przyspieszać