|
Hint
|
|
Answer
|
|
____ are composed of protons, neutrons and electrons
|
|
atoms
|
|
____ have charge +1 and mass 1
|
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protons
|
|
____ have charge 0 and mass 1
|
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neutrons
|
|
____ have charge -1 and mass 0
|
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electrons
|
|
the number of protons in the nucleus
|
|
atomic number/proton number
|
|
the number of protons and neutrons in the nucleus
|
|
mass number
|
|
atoms of the same element with different mass numbers
|
|
isotopes
|
|
relative atomic mass is an average of the isotopic masses accounting for their ____
|
|
abundance
|
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measures the atomic or molecular mass of different particles in a sample and the relative abundance of different isotopes in an element
|
|
mass spectrometry
|
|
in a mass spectrometer, sample atoms or molecules are ionised to ____
|
|
cations
|
|
these are then separated according to their ____
|
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mass to charge ratio
|
|
relative abundance can be calculated from the ____ of each peak on a mass spectrum
|
|
height
|
|
samples of an element may vary in Ar depending on their source due to different ____ of isotopes between samples
|
|
abundance
|
|
two light atomic nuclei fuse to form a single heavier nucleus of a new element, releasing energy
|
|
nuclear fusion
|
|
fusion requires high temperatures so the nuclei are moving ____ enough to overcome the repulsion
|
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fast/quickly
|
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____ theory of light: light is a form of electromagnetic radiation and so behaves as a wave with a wavelength and frequency
|
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wave
|
|
____ theory of light: light is a stream of photons
|
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particle
|
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____ of a photon = Planck constant x frequency
|
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energy
|
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speed of light = wavelength x ____
|
|
frequency
|
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when an atom is ____, electrons jump into higher energy levels
|
|
excited
|
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when electrons return to their ____, they emit the extra energy as electromagnetic radiation
|
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ground state
|
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the energy difference is emitted as electromagnetic radiation and can be used to give an ____
|
|
emission spectrum
|
|
an ____ is formed when white light is passed through a cool sample of a gaseous element
|
|
absorption spectrum
|
|
electrons in atoms only exist in definite energy levels. the certain definite quantities of energy are called ____
|
|
quanta
|
|
a ____ is emitted or absorbed when the electron changes energy levels
|
|
photon
|
|
in hydrogen, the emission lines are called the ____ series
|
|
Lyman
|
|
each electron shell is labelled first with n, the ____
|
|
principle quantum number
|
|
the higher the value of n, the ____ the shell from the nucleus and the higher the energy associated
|
|
further
|
|
shell n=n holds ____ electrons
|
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2n^2
|
|
shells have subshells s, p, d and f which can hold 2, 6, 10 and ____ electrons respectively
|
|
14/fourteen
|
|
____ are places in an atom where an electron is likely to be found
|
|
atomic orbitals
|
|
s, p, d and f subshells contain 1, 3, 5 and ____ orbitals respectively
|
|
7/seven
|
|
each orbital can hold a maximum of two electrons if they have ____ spins
|
|
opposite/paired
|
|
an s orbital is ____
|
|
spherical
|
|
a p orbital is shaped like a ____
|
|
peanut
|
|
the arrangement of electrons in shells and orbitals
|
|
electronic configuration
|
|
the orbitals are filled in order of increasing energy to produce the ____ energy arrangement possible
|
|
lowest
|
|
in an ____ atom, all orbitals in the same sub-shell have the same energy
|
|
isolated
|
|
only when all ____ in a sub-shell are occupied with one electron do the electrons pair up
|
|
orbitals
|
|
for the lowest energy arrangement, electrons in singly occupied orbitals have ____ spins
|
|
parallel
|
|
the modern periodic table is based on one proposed by ____
|
|
Mendeleev
|
|
electrons are organised into four blocks labelled s, p, d and ____
|
|
f
|
|
the s block is groups 1 and ____
|
|
2/two
|
|
the p block is groups 3 to ____
|
|
8/eight
|
|
the d block is the ____
|
|
transition metals
|
|
the f block is the ____ and actinides
|
|
lanthanides
|
|
elements in the same block show general similarities: e.g. all the non-metals are in the ____ block
|
|
p
|
|
vertical columns in the periodic table
|
|
groups
|
|
horizontal rows in the periodic table
|
|
periods
|
|
the occurrence of patterns across a period from left to right
|
|
periodicity
|
|
____ tend to increase from groups 1 to 4, then fall sharply and gradually decrease
|
|
melting points/boiling points
|
|
an element that has all of its sub-shells fully occupied by electrons has a ____ arrangement
|
|
closed shell
|
|
____ tends to create this
|
|
ionisation
|
|
shared pair of electrons
|
|
covalent bond
|
|
pair of electrons not involved in bonding
|
|
lone pair
|
|
both bonding electrons are donated by one atom in the pair
|
|
dative covalent bond
|
|
____ interactions between different simple molecules are weak, so melting and boiling points are low
|
|
electrostatic
|
|
because there are no charge particles, simple covalent molecules do not ____ electricity
|
|
conduct
|
|
they also do not usually dissolve readily in ____
|
|
water
|
|
you can determine the shape of a molecule by ____
|
|
valence shell electron pair repulsion theory/VSEPR
|
|
this means atoms arrange themselves to minimise ____
|
|
repulsion
|
|
lone pairs repel ____ strongly than bonding pairs
|
|
more
|
|
tetrahedral: 4 single covalent bonds, no lone pairs around the central atom, bond angle ____
|
|
109.5
|
|
trigonal pyramidal: 3 single covalent bonds, 1 lone pair around the central atom, bond angle ____
|
|
107
|
|
bent: 2 single covalent bonds, 2 lone pairs around the central atom, bond angle ____
|
|
104.5
|
|
linear: 2 groups of electrons around the central atom, bond angle ____
|
|
180
|
|
trigonal planar: 3 groups of electrons around the central atom, bond angle ____
|
|
120
|
|
ethene is ____
|
|
trigonal planar
|
|
trigonal bipyramidal: 5 groups of electrons around the central atom, bond angles 120 or ____ depending on the position in the molecule
|
|
90
|
|
octahedral: 6 groups around the central atom, bond angle ____
|
|
90
|
|
mass of an element's atom relative to carbon-12
|
|
relative atomic mass/Ar
|
|
mass of one mole
|
|
molar mass
|
|
this is equal to the Ar in ____
|
|
grams
|
|
____ = molar mass x mol
|
|
mass
|
|
sum of the constituent relative atomic masses is the relative formula mass or ____
|
|
Mr
|
|
the basic units that make up a substance that match the formulae of that substance
|
|
formula units
|
|
number of formula units in 1 mol
|
|
Avogadro constant/6.02x10^23
|
|
formula that tells you actual numbers of different types of atom per formula unit
|
|
molecular
|
|
formula that tells you the ratio of different types of atom per formula unit
|
|
empirical
|
|
water fitted regularly within the crystals of some ionic lattices
|
|
water of crystallisation
|
|
ionic compounds with this are ____
|
|
hydrated
|
|
when heated, this is removed as steam, leaving the ____ solid
|
|
anhydrous
|
|
expected amount of product in a reaction carried out under ideal conditions
|
|
theoretical yield
|
|
factors that can reduce amount of product produced include: (1) loss of product from reaction ____
|
|
vessels
|
|
(2) ____ occurring and producing unwanted by-products
|
|
side reactions
|
|
(3) ____ in the reactants
|
|
impurities
|
|
(4) changes in ____ and pressure if the reaction is an equilibrium system
|
|
temperature
|
|
how much product you actually get
|
|
experimental yield
|
|
(experimental yield / theoretical yield) x 100
|
|
percentage yield
|
|
positively charged ions
|
|
cations
|
|
negatively charged ions
|
|
anions
|
|
ions are only formed when ____ react with non-metals if the overall energy change is favourable
|
|
metals
|
|
electrons are transferred from the metal to the non-metal atoms, often giving both a ____ electronic structure
|
|
stable
|
|
anions and cations are held together by opposite charges in an ____ attraction
|
|
electrostatic
|
|
in a solid compound, each ion attracts many others of opposite charge and a giant ____ builds up
|
|
lattice
|
|
acid + base/alkali => salt + ____
|
|
water
|
|
acid + carbonate => salt + water + ____
|
|
carbon dioxide
|
|
acid + metal => salt + ____
|
|
hydrogen
|
|
many ionic substances dissolve readily in ____
|
|
water
|
|
this excludes: (1) silver and lead ____
|
|
halides
|
|
(2) all metal ____
|
|
carbonates
|
|
(3) barium, calcium, lead and silver ____
|
|
sulfates
|
|
(4) all metal ____ (except group 1)
|
|
hydroxides
|
|
when ionic substances ____, the ions becomes surrounded by water molecules and spread out through the solution
|
|
dissolve
|
|
they behave independently of each other, which is why ____ solutions of salts conduct electricity
|
|
aqueous
|
|
ionic reactions in solution that forms a solid precipitate
|
|
ionic precipitation
|
|
ions that don't take part in the reaction
|
|
spectator ions
|
|
when a solution of sodium hydroxide is added to a solution of ____, the following colour forms:
|
|
ions/metal ions
|
|
(1) copper 2+
|
|
blue
|
|
(2) iron 2+
|
|
dirty green
|
|
(3) iron 3+
|
|
orange brown
|
|
potassium iodide + lead 2+ forms a ____ precipitate
|
|
bright yellow
|
|
precipitate colour of silver nitrate + nitric acid + halide ion: (1) chloride
|
|
white
|
|
(2) bromide
|
|
cream
|
|
(3) iodide
|
|
pale yellow
|
|
barium chloride + sulfate ions forms a ____ precipitate
|
|
white
|
|
ionic compounds are typically ____ at room temperature, have a 3D lattice structure and often form regular crystals
|
|
solids
|
|
attraction overcomes repulsion between ions so ionic compounds have high ____
|
|
melting points/boiling points
|
|
once ____ or dissolved, they can conduct electricity
|
|
molten
|
|
metals have a lattice structure of metal cations in a sea of ____ valence electrons
|
|
delocalised
|
|
metals have high melting and boiling points due to the ____ attractions between cations and electrons
|
|
electrostatic
|
|
metals ____ electricity as the electrons are free to move
|
|
conduct
|
|
covalent networks can also form, which have strong ____ bonds between atoms in the network
|
|
covalent
|
|
they have high melting and boiling points and are ____ soluble in water
|
|
not
|
|
they do not usually conduct electricity, excepting ____
|
|
graphite
|
|
elements become more ____ down a group (more readily form cations) and less across a period
|
|
metallic
|
|
energy needed to remove one mole of the most loosely held electrons from one mole of isolated gaseous ions to create one mole of gaseous ions with a +1 charge
|
|
first ionisation enthalpy
|
|
this increases across a period because the nuclear charge becomes more positive but the ____ stays very similar
|
|
atomic radius
|
|
it decreases down a group because of more ____
|
|
electronic shielding
|
|
metal oxides and hydroxides form ____ solutions in water but are not very soluble
|
|
alkaline
|
|
non-metals form ____ solutions
|
|
acidic
|
|
the most strongly alkaline oxides and hydroxides are at the ____ of the group
|
|
bottom
|
|
as you go down group two: (1) reactivity with water ____
|
|
increases
|
|
(2) pH of the hydroxide in water ____
|
|
increases
|
|
(3) solubility of the hydroxide ____
|
|
increases
|
|
(4) solubility of the carbonate ____
|
|
decreases
|
|
the change in ____ of the carbonates is due to charge density of the cations
|
|
thermal stability
|
|
cations with a higher charge density can ____ the negative charge cloud around the carbonate ion
|
|
polarise
|
|
this makes it ____ thermally stable so breaks down more easily on heating
|
|
less
|
|
proton donors that dissociate in water to produce hydrogen ions
|
|
acids
|
|
protons acceptors that react with an acid to produce water and a salt
|
|
bases
|
|
this theory of H+ transfer is the ____ theory of acids and bases
|
|
Bronsted Lowry
|
|
____ theory is that bases are electron pair donors, acids electron pair acceptos
|
|
Lewis
|
|
H3O+ is the ____ ion
|
|
oxonium
|
|
it occurs in acidic solution. it has 2 simple covalent bonds and 1 ____ covalent bond
|
|
dative
|
|
this is where the oxygen atom donates both bonding electrons to a ____
|
|
proton
|
|
it can also act as an acid, donating H+ and becoming a ____ molecule
|
|
water
|
|
acid + alkali reaction is called a ____ reaction
|
|
neutralisation
|
|
neutralisation ____ equation: H+ + OH- => H2O
|
|
ionic
|
|
reaction that releases more energy making bonds than it requires to break bonds
|
|
exothermic
|
|
reaction that releases less energy making bonds than it requires to break bonds
|
|
endothermic
|
|
the reactants and products of a reaction
|
|
system
|
|
everything else
|
|
surroundings
|
|
298K, 101kPa, concentration 1 mol dm^-3 for solutions - these are called ____ conditions
|
|
standard
|
|
the enthalpy change when molar quantities of reactants react together under standard conditions
|
|
standard enthalpy change
|
|
energy = specific heat capacity x mass x ____ change
|
|
temperature
|
|
you can use a ____ to measure enthalpy changes
|
|
bomb calorimeter
|
|
here, energy in a reaction is transferred from a reaction vessel to the surrounding ____
|
|
water
|
|
the enthalpy change that occurs when one mole of a substance is burnt completely in oxygen under standard conditions
|
|
standard enthalpy change of combustion
|
|
the enthalpy change when one mole of a compound is formed from its elements under standard conditions
|
|
standard enthalpy change of formation
|
|
the enthalpy change when one mole of hydrogen ions react with one mole of hydroxide ions to form one mole of water under standard conditions
|
|
standard enthalpy change of neutralisation
|
|
the energy needed to raise the temperature of 1g of a substance by 1K
|
|
specific heat capacity
|
|
____ law - enthalpy change for any chemical reaction is independent of the route taken so long as the initial and final conditions are the same
|
|
Hess
|
|
you can calculate enthalpy change of a reaction indirectly using ____
|
|
enthalpy cycles
|
|
the property of carbon to form covalent bonds with itself
|
|
catenation
|
|
compounds with one or more benzene rings
|
|
aromatic
|
|
compounds without benzene rings
|
|
aliphatic
|
|
modifiers responsible for the chemical reactions of molecules
|
|
functional groups
|
|
saturated hydrocarbon, can be straight or branched
|
|
alkane
|
|
a series of related compounds with the same general molecular formulae
|
|
homologous series
|
|
at room temperature the first four alkanes are ____
|
|
colourless gases
|
|
higher members are ____
|
|
colourless liquids
|
|
larger alkanes, n=17+, are ____
|
|
white waxy solids
|
|
alkanes mix well with each other but do not mix with ____ because they are non-polar
|
|
water
|
|
the average quantity of energy needed to break a particular bond in the gaseous state
|
|
bond enthalpy
|
|
the equilibrium ____ is the balance between the attractive forces of the nuclei and electrons and repulsive forces between nuclei
|
|
bond length
|
|
some reactions need ____ heating, but many do not
|
|
continuous
|
|
this is because if a few bonds break, new bonds can start to ____, which usually gives out enough energy to keep the reaction going
|
|
form
|
|
bond enthalpies are often averages from several ____
|
|
compounds
|
|
a substance which increases the rate of a reaction by offering an alternate reaction pathway with lower activation energy
|
|
catalyst
|
|
the process of increasing rate of reaction using a catalyst
|
|
catalysis
|
|
catalysts are recovered ____ at the end of a reaction
|
|
chemically unchanged
|
|
catalysis where both catalyst and reactants are in the same physical state
|
|
homogeneous
|
|
catalysis where catalyst and reactants are in different physical states
|
|
heterogeneous
|
|
usually, heterogeneous catalysis involves a mixture of gases and liquids reacting in the presence of a ____ catalyst
|
|
solid
|
|
(1) reactants are ____ onto the surface of the catalyst by forming bonds
|
|
adsorbed
|
|
(2) bonds in the ____ molecules are weakened and break
|
|
reactant
|
|
(3) new bonds form between the ____, held close together on the catalyst's surface
|
|
atoms/reactants
|
|
(4) this weakens the bonds to the catalyst surface and the produces are ____
|
|
desorbed
|
|
a catalyst should have a large ____ for contact with reactants
|
|
surface area
|
|
____ catalysts are used as a finely divided form or as a fine wire mesh to maximise this
|
|
solid
|
|
sometimes the catalyst is supported on a ____ to increase surface area and prevent crumbling
|
|
porous material
|
|
this occurs in ____
|
|
catalytic converters
|
|
many heterogeneous catalysts are ____
|
|
transition metals
|
|
catalysts can be ____ so they no longer function properly
|
|
poisoned
|
|
the poisons are adsorbed ____ strongly to the catalyst surface than the reactant molecules, reducing surface area available for catalysis
|
|
more
|
|
platinum and ____ are used in catalytic converters rather than cheaper metals
|
|
rhodium
|
|
this is because cheaper metals are vulnerable to poisoning by trace ____ in the car exhaust
|
|
sulfur dioxide
|
|
the ____ catalyst in the Haber process can be poisoned if the feedstock contains sulfur compounds, so these are removed first
|
|
nickel
|
|
you can ____ the surface of a poisoned catalyst
|
|
regenerate
|
|
for example in the catalytic cracking of ____ hydrocarbons, carbon is produced
|
|
long chain
|
|
catalytic cracking uses a ____ catalyst (contains aluminium oxide and silicon dioxide) and temperatures about 550C
|
|
zeolite
|
|
the catalyst surface becomes coated in soot, blocking ____
|
|
adsorption
|
|
the catalyst is constantly recycled through a separate container and blown with hot air - oxygen converted carbon to ____ and regenerates the catalyst
|
|
carbon dioxide
|
|
alkenes have a carbon carbon ____ so are unsatured
|
|
double bond
|
|
single bond, so called due to the overlap of s orbitals
|
|
sigma
|
|
a double bond contains one sigma bond and one ____ bond
|
|
pi
|
|
pi bonds consist of two areas of ____, one above and one below the plane of the atoms
|
|
negative charge/electron density
|
|
the four electrons in ethene's double bond gives the region a high ____ of negative charge
|
|
density
|
|
a positive ion or a molecule with a partial positive charge that will be attracted to a negatively charged region and react by accepting a lone pair of electrons to form a covalent bond
|
|
electrophile
|
|
bubbling ethene gas through bromine ____ the bromine
|
|
decolorises
|
|
as it approaches the alkene, the bromine molecule becomes ____
|
|
polarised
|
|
the ____-positive bromine atom behaves as an electrophile and reacts with the alkene double bond
|
|
partially/delta
|
|
this leaves a bromide ion and a ____
|
|
carbocation
|
|
the bromide ion donates a ____ to the positively charged carbon to form a new C-Br bond
|
|
pair of electrons/electron pair/lone pair
|
|
two or more molecules react to form a single, larger molecule
|
|
addition
|
|
shaking an alkene with water ____ the bromine water
|
|
decolorises
|
|
water molecules have lone pairs of electrons and can act as ____ in competition with bromide ions in the second stage of the mechanism
|
|
nucleophiles
|
|
therefore, a ____ might be produced (still colourless)
|
|
bromoalcohol
|
|
ethene reacts with a solution of ____ in a polar solvent at room temperature
|
|
hydrogen bromide
|
|
it can also react with gaseous HBr but this involves a ____
|
|
radical addition
|
|
at ____ temperature, ____ pressure, and in the presence of a catalyst, ethene and steam can undergo an addition reaction
|
|
high
|
|
the catalyst is ____ acid adsorbed onto solid silica
|
|
phosphoric acid
|
|
in the laboratory, ethene can be converted to ethanol by first adding concentrated ____
|
|
sulfuric acid
|
|
this forms ____
|
|
ethyl hydrogensulfate
|
|
this can then be diluted with ____ to form the ethanol
|
|
water
|
|
adding a molecule of water across a double bond is a ____ reaction
|
|
hydration
|
|
reaction that saturates an unsaturated molecule
|
|
hydrogenation
|
|
for this, you can use (1) a ____ catalyst under standard laboratory conditions
|
|
platinum
|
|
(2) a finely powdered ____ catalyst at high temperature and pressure
|
|
nickel
|
|
a long molecule made up from many smaller monomers
|
|
polymer
|
|
the process by which monomers join to produce long chain polymers
|
|
polymerisation
|
|
a polymerisation where no byproducts are formed and the monomers tend to contain C=C bonds
|
|
addition
|
|
more than one monomer is incorporated into the final polymer
|
|
copolymerisation
|
|
____ combustion forms carbon dioxide and water when carbon-based fuels burn
|
|
complete
|
|
the volume occupied by one mole of any gas at a particular temperature and pressure
|
|
molar volume
|
|
at room temperature, this is ____ dm^3
|
|
24
|
|
pV = nRT is the ____ equation
|
|
ideal gas
|
|
units are: Pa, ____, J, K^-1 mol^-1, K respectively
|
|
m^3/metres cubed
|
|
same molecular formula, atoms bonded together in a different order
|
|
structural isomerism
|
|
different arrangement of the carbon atoms
|
|
chain isomerism
|
|
different position of the functional group
|
|
position isomerism
|
|
same molecular formula but different functional group
|
|
functional group isomerism
|
|
same structural formula, different arrangement of atoms in space
|
|
stereoisomerism
|
|
both of the two heaviest groups are on the same side of the molecule
|
|
Z stereoisomer
|
|
the two heaviest groups are on opposite sides of the molecule
|
|
E-stereoisomer
|
|
stereoisomers form because the carbon-carbon double bond cannot ____ due to the overlap of p orbitals
|
|
rotate
|
|
small carbon particles generated by burning fuels. penetrate deep into the human body and cause heart attacks and lung cancer
|
|
particulates
|
|
compounds that come from unburnt fuel. cause photochemical smog
|
|
volatile organic compounds/VOCs
|
|
formed from incomplete combustion of fuels. toxic, causes photochemical smog
|
|
carbon monoxide
|
|
comes from combustion of fuels. greenhouse effect
|
|
carbon dioxide
|
|
comes from combustion of fuels. acid rain, photochemical smog
|
|
nitrogen oxides
|
|
burning of sulfur-containing fuels. acid raid, toxic gas
|
|
sulfur oxides
|
|
____ reacts with water in the atmosphere to form sulfuric (IV) acid
|
|
sulfur dioxide
|
|
sulfur dioxide can be oxidised to ____ which reacts with water to form sulfuric (VI) acid
|
|
sulfur trioxide
|
|
nitrogen oxide and nitrogen dioxide react with atmospheric water and oxygen to form ____ (V) acid
|
|
nitric
|
|
formed when primary pollutants are acted on by sunlight. causes haziness, reduced visibility, respiratory problems
|
|
photochemical smog
|
|
pollutants formed or emitted directly from particular sources
|
|
primary
|
|
pollutants formed by chemical reactions of primary pollutants
|
|
secondary
|
|
____ remove pollutants in exhaust
|
|
catalytic converters
|
|
in petrol engines: a ____ catalytic converter is used
|
|
three-way
|
|
(1) carbon monoxide is converted to carbon dioxide by adding ____
|
|
oxygen
|
|
(2) hydrocarbons are converted to ____ and water by adding oxygen
|
|
carbon dioxide
|
|
(3) nitrogen monoxide reacts with carbon monoxide to form ____ and carbon dioxide
|
|
nitrogen
|
|
____ engines remove nitrogen monoxide and hydrocarbons in the same way
|
|
diesel
|
|
particulates are removed by ____
|
|
ceramic filters
|
|
regeneration of the catalyst is accomplished by periodically increasing the ____
|
|
temperature
|
|
____ oxides can be reduced by recycling some of the exhaust gases through the cylinder, decreasing temperature
|
|
nitrogen
|
|
you can also use an ____ reagent:
|
|
ammonia
|
|
nitrogen oxide + ammonia + oxygen => nitrogen + ____
|
|
water
|
|
for both petrol and diesel engines, ____ is best avoided by using low sulfur fuels
|
|
sulfur dioxide
|
|
made by fermentation of carbohydrate crops
|
|
ethanol
|
|
cars cannot run on ethanol alone as it's too ____
|
|
volatile
|
|
however, it can be used in mixtures of petrol up to ____ percent
|
|
15
|
|
ethanol can be said to be ____ because carbon dioxide released in burning and fermentation matches the carbon dioxide absorbed in the growing plant
|
|
carbon neutral
|
|
however, does not account for ____ used to produce and distribute the ethanol
|
|
energy/fuel
|
|
made by chemically reacting fats and oils with alcohols
|
|
biodiesel
|
|
reaction of fats and oils with alcohols to produce fatty acid esters
|
|
trans-esterification
|
|
biodiesel can be made from ____
|
|
waste oil
|
|
biodiesel is ____ except for energy used to produce and distribute
|
|
carbon neutral
|
|
biodiesel is ____ if spilled
|
|
biodegradable
|
|
biodiesel contains virtually no ____ and produces less CO, particulates and hydrocarbons than petrol and diesel
|
|
sulfur
|
|
however, biodiesel produces more ____ than conventional fossil fuels
|
|
nitrogen oxides
|
|
two other examples of biofuels are ____ and biogas
|
|
green diesel
|
|
combustion of hydrogen produces only ____
|
|
water
|
|
benefits of hydrogen fuel: (1) renewable and can be made from ____ of water
|
|
electrolysis
|
|
(2) can be stored and sent down ____ (like how methane is currently)
|
|
pipelines
|
|
(3) can be used in ____ or fuel cells to generate electricity
|
|
internal combustion engines
|
|
(4) produces no CO2, CO or ____ when burnt
|
|
hydrocarbons
|
|
however, its production of water often depends on energy from ____ power stations
|
|
fossil fuel
|
|
it's also less ____ than petrol
|
|
energy dense
|
|
____ are still produced
|
|
oxides of nitrogen/nitrogen oxides
|
|
____ generate electricity on a small scale in cars
|
|
fuel cells
|
|
the main problem is that a large volume of ____ hydrogen is required to get the mileage equivalent to a full tank of petrol
|
|
gaseous
|
|
one solution is storing it as a ____ in a high-pressure fuel tank
|
|
liquid
|
|
the ____ are in group 7, the p-block
|
|
halogens
|
|
they all have 7 ____ electrons and abundance decreases down the group
|
|
valence/outer shell
|
|
all halogens occur as ____ molecules
|
|
diatomic
|
|
at room temperature: (1) fluorine is a ____
|
|
pale yellow gas
|
|
(2) chlorine is a ____
|
|
green gas
|
|
(3) bromine is a ____
|
|
dark red volatile liquid
|
|
(4) iodine is a ____
|
|
shiny grey black solid
|
|
iodine ____ to give purple vapour on heating
|
|
sublimes
|
|
going down the group, the halogens become darker, have ____ melting and boiling points, become less volatile
|
|
increased
|
|
the halogens are ____ soluble in organic solvents than water
|
|
more
|
|
dissolved in water: (1) chlorine is ____
|
|
pale green
|
|
(2) bromine is ____
|
|
orange yellow
|
|
(3) iodine is ____
|
|
brown
|
|
dissolved in cyclohexane: (1) chlorine is ____
|
|
pale green
|
|
(2) bromine is ____
|
|
orange brown
|
|
(3) iodine is ____
|
|
violet
|
|
fluorine is the most reactive of the halogens and is the strongest ____
|
|
oxidising agent
|
|
this is because fluorine atoms are the ____ so the attraction between the nucleus and the outer shell is the greatest
|
|
smallest
|
|
more reactive halogens can ____ less reactive halogens from an aqueous solution of their salts
|
|
displace
|
|
this is a ____ reaction
|
|
redox
|
|
the less reactive halogen is ____ and the more reactive halogen reduced
|
|
oxidised
|
|
adding nitric acid and silver nitrate to an aqueous solution of a halide precipitates a ____
|
|
silver halide
|
|
when ____ solution is added, solubility of the silver halide decreases down the group
|
|
ammonia
|
|
how many electrons have been lost or gained compared to the unreacted element
|
|
oxidation state
|
|
increases when something is ____ and decreases when it is reduced
|
|
oxidised
|
|
for an element, oxidation state = ____
|
|
0
|
|
for a simple ion, = ____ of the ion
|
|
charge
|
|
for a compound, overall oxidation states of constituent elements sum to ____
|
|
0
|
|
for a complex ion, overall oxidation states sum to the ____ of the ion
|
|
charge
|
|
a negative ion with oxygen in it
|
|
oxyanion
|
|
chlorine can form ____ oxyanions, where chlorine's oxidation state can be +1 +3 +5 or +7
|
|
chlorate
|
|
balanced equations
|
|
stochiometric
|
|
breakdown of a compound using electricity
|
|
electrolysis
|
|
negative electrode where reduction occurs
|
|
cathode
|
|
positive electrode where oxidation occurs
|
|
anode
|
|
if electrolysis occurs in an ____ solution of a salt, water competes with the ions from the salt
|
|
aqueous
|
|
at the cathode, ____ will form unless the metal present is less reactive than hydrogen
|
|
hydrogen
|
|
equation: 2H2O + 2e- => 2____ + H2
|
|
OH-
|
|
at the anode, oxygen will form unless a ____ ion is present
|
|
halide
|
|
equation: 2H2O => O2 + 4____ + 4e-
|
|
H+
|
|
concentrations of reactants and products are constant, both forward and reverse reactions happen at equal rates
|
|
dynamic equilibrium
|
|
Kc is the ____ and it's a measure of how much product compared to reactant there is
|
|
equilibrium constant
|
|
if Kc is greater than one, there is more ____
|
|
product
|
|
if a system at ____ is changed by adding more of a reagent, the system will counteract that change to maintain position of ____
|
|
equilibrium
|
|
therefore Kc will not change provided ____ is constant
|
|
temperature
|
|
chlorine is toxic and irritates the eyes, skin and ____
|
|
respiratory system
|
|
inhaling chlorine at high concentrations can cause it to react in the lungs to form ____
|
|
hydrochloric acid
|
|
chlorine is transported in pressurised tank containers as a ____
|
|
liquid
|
|
there are pressure release devices designed to vent the tank to prevent it ____ if pressure becomes too high
|
|
exploding
|
|
the tanks are made and lined with ____
|
|
steel
|
|
this must be dry as chlorine and water react to produce ____ acids
|
|
corrosive
|
|
all loading and unloading is done through the ____ at the top of the tank
|
|
protective housing
|
|
there is an ____on large chlorine tanks
|
|
excess flow valve
|
|
this closes automatically if the ____ that regulates discharge of chlorine is broken
|
|
angle valve
|
|
a ____ ensures that air displaced from the bulk trailer has chlorine removed from it
|
|
scrubber unit
|
|
the ____ is what chlorine is transferred to on site
|
|
bulk trailer
|
|
the scrubber unit has ____ solution that reacts with the chlorine to produce sodium chlorate (I)
|
|
sodium hydroxide
|
|
to check if chlorine cylinders are leaking, a stick with a cloth soaked in ____ is held near the tank
|
|
concentrated ammonia solution
|
|
if it's leaking, a white cloud of ____ will be seen
|
|
ammonium chloride
|
|
chlorine has many uses such as in ____ treatment and in bleach products
|
|
water
|
|
____ titrations can be used to find the concentration of sodium thiosulfate
|
|
iodine thiosulfate
|
|
sodium thiosulfate is a strong enough oxidising agent to oxidise ____ ions
|
|
iodide
|
|
the end point can be identified by adding ____ solution
|
|
starch
|
|
the end point is marked by the solution turning ____
|
|
colourless
|
|
(relative formula mass of desired product / relative formula mass of all reactants used) x 100
|
|
atom economy
|
|
____ is often made as a co-product from the chlorination of organic compounds
|
|
hydrochloric acid
|
|
for example, when poly(____) is made, the first stage is reacting ethene with chlorine
|
|
chloroethane
|
|
this then undergoes ____ to give chloroethane and hydrogen chloride
|
|
thermal cracking
|
|
HCl can be converted to hydrochloric acid if passed through ____
|
|
water
|
|
sodium fluoride and sodium chloride both react with concentrated acid to make ____ fluoride/chloride gas
|
|
hydrogen
|
|
you can see ____ of hydrogen chloride as HCl gas meets moist air
|
|
white fumes
|
|
sodium bromide reacts with concentrated sulfuric acid to make ____
|
|
hydrogen bromide
|
|
the bromide ions are also strong enough reducing agents to reduce sulfuric acid to ____
|
|
sulfur dioxide
|
|
sodium iodide reacts with concentrated sulfuric acid to make ____
|
|
hydrogen iodide
|
|
the iodide ions are stronger reducing agents than bromide, so can reduce the sulfur in the acid further to make ____ gas
|
|
hydrogen sulfide
|
|
to prepare pure hydrogen bromide or iodide, concentrated ____ should be used instead as it won't be reduced
|
|
phosphoric acid
|
|
____ of the hydrogen halides decreases down the group because bond strength decreases
|
|
thermal stability
|
|
when heated in a laboratory: (1) hydrogen fluoride and hydrogen chloride are ____ broken down into their elements
|
|
not
|
|
(2) some brown bromine ____ is made when HBr is heated strongly
|
|
gas
|
|
(3) large amounts of purple gaseous iodine are made if a ____ is plunged into gaseous iodide
|
|
red hot needle
|
|
in solution, the soluble hydrogen halides are all ____
|
|
acidic
|
|
apart from HF they are ____ acids (almost 100% dissociation for HCl, HBr and HI)
|
|
strong
|
|
all of the hydrogen halides react with ____ to make ammonium salts
|
|
ammonia
|
|
if a glass rod is dipped in concentrated ____ solution then placed in the hydrogen halide, a white cloud of ammonium halide is made
|
|
ammonia
|
|
if a system is at equilibrium and a change is made in any of the conditions then the system will oppose the change
|
|
Le Chatelier's principle
|
|
gas concentrations can be expressed as ____ (ppm)
|
|
parts per million
|
|
a molecule has energy associated with several aspects of its behaviour including (1) the molecule moving around
|
|
translation
|
|
(2) ____ of the whole molecule
|
|
rotation
|
|
(3) ____ of the bonds
|
|
vibration
|
|
(4) ____ energy
|
|
electron
|
|
all of these energies are ____
|
|
quantised
|
|
we sense ____ radiation as heat as the radiation increases vibrational energy of the bonds in skin
|
|
infrared
|
|
spacing between energy levels: translational ____ rotational ____ vibrational ____ electron
|
|
</less than
|
|
if a molecule absorbs ultraviolet radiation, one of three things might happen: (1) ____ may be excited to a higher energy level
|
|
electrons
|
|
(2) ____ which forms radicals
|
|
photodissocation
|
|
atoms or molecules with at least one unpaired electron
|
|
radicals
|
|
(3) the molecule may be ____ with very high energy photons
|
|
ionised
|
|
bonds are broken
|
|
bond fission
|
|
the shared electrons go to just one of the atoms when the bond breaks
|
|
heterolytic fission
|
|
common when a bond is ____. one atom becomes negatively charged and one positively
|
|
polar
|
|
one of two shared electrons go to each atom
|
|
homolytic fission
|
|
the unpaired electron has a strong tendency to pair up again with another ____
|
|
electron
|
|
these atoms have no overall charge and are most commonly formed when the bond being broken is ____
|
|
non polar
|
|
polar bonds can also break in this way if the reaction is occurring in the ____ phase in the presence of light
|
|
gas
|
|
photodissocation of a stronger bond requires higher energy (____ wavelength) light than a weaker bond
|
|
shorter
|
|
radicals are ____ because filled electron shells are more stable than unfilled ones
|
|
reactive
|
|
radical chain reactions have ____ key stages
|
|
3/three
|
|
(1) radicals are formed by photodissociation and soon react with something else
|
|
initiation
|
|
(2) the radicals react with other molecules and produce new radicals
|
|
propagation
|
|
(3) two radicals collide, removing them from the reaction
|
|
termination
|
|
a reaction will only occur if particles of reactants collide with sufficient energy
|
|
collision theory
|
|
minimum energy required for a reaction to be successful
|
|
activation enthalpy
|
|
can be used to picture energy changes as a reaction occurs
|
|
enthalpy profile
|
|
the highest point on the pathway where old bonds stretch and new ones start to form
|
|
transition state
|
|
the distribution of kinetic energies in a gas at a given temperature
|
|
Maxwell Boltzmann
|
|
plots ____ energy against fraction of particles with that energy
|
|
kinetic
|
|
as temperature ____, the curve will shift right and the peak will be lower
|
|
increases
|
|
the ____ under the curve remains the same
|
|
area
|
|
for many reactions, rate is roughly doubled by a ____K increase in temperature
|
|
10
|
|
the enthalpy profile for a catalyst has 2 humps because an ____ is formed
|
|
intermediate
|
|
the destruction of ozone in the ____ by chlorine and bromine is homogeneous catalysis
|
|
stratosphere
|
|
the reaction of ozone with Cl radicals 1500x faster than with ____ radicals and Br is 10x faster than that
|
|
O
|
|
the Cl and Br radicals are ____ so a single Cl can remove about 1 million ozone molecules
|
|
reformed
|
|
overall reaction: O + O3 -> 2____
|
|
O2
|
|
____ radicals form when oxygen reacts with water in the stratosphere
|
|
hydroxyl
|
|
this forms ____ and oxygen
|
|
hydrogen dioxide
|
|
the HO2 radicals then react with oxygen atoms to ____ the hydroxyl radicals
|
|
reform
|
|
____ reacts with ozone to form nitrogen dioxide and dioxygen
|
|
nitrogen monoxide
|
|
____ then reacts with oxygen atoms to release nitrogen monoxide and dioxygen
|
|
nitrogen dioxide
|
|
NO and NO2 are both radicals but are unusual because they are quite ____
|
|
stable
|
|
the tendency of an atom in a molecule to attract electrons in a chemical bond
|
|
electronegativity
|
|
when atoms are unequally electronegative, one gets a slightly negative charge, creating a ____ bond
|
|
polar
|
|
carbon-halogen bonds in ____ are polar but not enough to make a large difference to the physical properties of the compounds
|
|
haloalkanes
|
|
the bigger the halogen atom and the ____ halogen atoms there are, the higher the boiling point
|
|
more
|
|
intermolecular forces are stronger the ____ an alkane's chain is
|
|
longer
|
|
straight chain alkanes have ____ boiling points than branched ones due to more contacts between molecules for intermolecular bonds to form
|
|
higher
|
|
a molecule or part of a molecule with a positive and negative end
|
|
dipole
|
|
____ dipoles occur when atoms in a bond have different electronegativities
|
|
permanent
|
|
a molecule with polar bonds can have no overall dipole if one charge is ____ on the other (e.g. tetrachloromethane)
|
|
superimposed
|
|
electrons are in constant motion. when unevenly distributed, an ____ occurs
|
|
instantaneous dipole
|
|
an ____ dipole occurs when an unpolarised molecule is next to a dipole
|
|
induced
|
|
you can have: instantaneous ____ induced ____ bonds, permanent ____ induced ____ bonds, permanent ____ permanent ____ bonds
|
|
dipole
|
|
the halogens form only ____ bonds. the boiling points increase down the group because as the size of the atoms increases these become stronger
|
|
instantaneous dipole induced dipole
|
|
for a ____ bond to form:
|
|
hydrogen
|
|
(1) there must be a large dipole between a hydrogen atom and a highly ____ atom such as O, N or F
|
|
electronegative
|
|
(2) there must be a ____ atom in a nearby molecule which can get very close to the O, N or F
|
|
hydrogen
|
|
(3) there must be a ____ on the O, N or f for the positively charged hydrogen atom to line up with
|
|
lone pair
|
|
compounds with hydrogen bonding have ____ boiling points as they require a lot of energy to break
|
|
higher
|
|
liquids with hydrogen bonding have high ____ (flow requires breaking and reformation of intermolecular bonds which is harder with stronger bonds)
|
|
viscosity
|
|
substances with hydrogen bonding are often ____-soluble as hydrogen bonds can form between solute and solvent
|
|
water
|
|
when water freezes it forms ice crystals - an open structure with ____ hydrogens around each oxygen atom to maximise hydrogen bonding
|
|
4/four
|
|
haloalkanes are formed by a ____ halogenation mechanism
|
|
radical
|
|
homolytic fission of haloalkanes occurs in the stratosphere when exposed to ____
|
|
ultraviolet radiation
|
|
heterolytic fission is more common under laboratory conditions because the carbon-halogen bond is ____
|
|
polar
|
|
sometimes this is caused by a nucleophile attacking the partially positive carbon atom, causing a ____ reaction
|
|
substitution
|
|
a molecule or ion with a lone pair of electrons that it can donate to a positively charged atom to form a covalent bond
|
|
nucleophile
|
|
(1) the nucleophile attacks the delta-positive carbon and donates two electrons to form a new ____ covalent bond
|
|
dative
|
|
(2) the C-X bond breaks heterolytically and the halogen receives two electrons, producing a ____ ion
|
|
halide
|
|
the group that leaves the molecule
|
|
leaving group
|
|
heating a haloalkane in a sealed tube with concentrated ammonia can produce an ____
|
|
amine
|
|
you can use nucleophilic substitution to produce a haloalkane from an alcohol in the presence of a ____
|
|
strong acid
|
|
an H+ binds to the ____ on the alcohol group, giving the carbon atom a higher partial positive charge and making it more readily attacked
|
|
oxygen
|
|
bond ____ and bond strength both decrease down the group
|
|
polarity
|
|
rate of ____ of a carbon halogen bond is determined by bond strength
|
|
hydrolysis
|
|
____ are polar due to the polarised OH bond, so can form hydrogen bond
|
|
alcohols
|
|
they become less ____ as the hydrocarbon chain becomes longer and the influence of the OH group decreases
|
|
soluble
|
|
alcohols with an -OH bonded to a carbon bonded to one other carbon atom
|
|
primary
|
|
alcohols with an -OH bonded to a carbon bonded to two other carbon atoms
|
|
secondary
|
|
alcohols with an -OH bonded to a carbon bonded to three other carbon atoms
|
|
tertiary
|
|
acidified potassium ____ can be used to oxidise primary and secondary alcohols
|
|
dichromate
|
|
the OH group is converted to a ____ group, and the reaction mixture turns from orange to green
|
|
carbonyl
|
|
primary alcohols are initially oxidised to ____
|
|
aldehydes
|
|
further reflux with excess oxidising agent can oxidise them to ____
|
|
carboxylic acids
|
|
secondary alcoholes are oxidised to ____ but not further because that would involve breaking a strong carbon carbon bond
|
|
ketones
|
|
tertiary alcohols are not oxidised because there is no ____ atom on the carbon atom to which the -OH is attached
|
|
hydrogen
|
|
____ is a safe method for heating volatile and flammable liquids
|
|
reflux
|
|
the liquid is boiled with a vertically mounted ____ so the vapour condenses and returns back into the reaction mixture
|
|
condenser
|
|
many alcohols can lose a molecule of water to form an ____ and water (dehydration, elimination)
|
|
alkene
|
|
this requires a heated alumina catalyst at ____ degrees C or reflux with concentrated sulfuric acid
|
|
300
|
|
you can ____ an alcohol with carboxylic acid or acid anhydride
|
|
esterify
|
|
carboxylic acid: slow, requires strong acid catalyst and heating under reflux, reaction comes to ____
|
|
equilibrium
|
|
the ester can then be separated from the mixture by ____ and purified
|
|
distillation
|
|
acid anhydride: react completely with an alcohol on warming to give a higher yield of ester, also produce a ____
|
|
carboxylic acid
|
|
____ are functional group isomers of alcohols and have formula R-O-R
|
|
ethers
|
|
they are derived from alkanes by substituting an ____ group (-OR) gor a hydrogen atom
|
|
alkoxy
|
|
the OH group reacts with water to form ____ so behaves as an acid
|
|
oxonium
|
|
in order of acid strength: ethanol ____ water ____ phenol ____ carboxylic acids
|
|
>
|
|
phenols and carboxylic acids react with ____ bases to produce ionic salts but only carboxylic acids can react with weak bases
|
|
strong
|
|
iron (IIII) chloride solution turns from yellow to pink in the presence of a ____
|
|
phenol
|
|
you can esterify ____ (salicylic) acid in two ways because it has both a phenol and carboxylic acid group
|
|
2-hydroxybenzoic
|
|
(1) esterify the phenol group to form ____ (aspirin) - water soluble, can be absorbed into the bloodstream through the stomach wall
|
|
2-ethanoyloxybenzoic acid
|
|
(2) react the -COOH with methanol to form ____ (oil of wintergreen) which is used as a linament - fat soluble, absorbed through the skin
|
|
methyl 2-hydroxybenzoate/methyl salicylate
|
|
both esters are used to reduce pain and ____
|
|
swelling/inflammation
|
|
infrared spectroscopy: substances are exposed to infrared radiation and their bonds absorb different ____
|
|
wavelengths
|
|
the part of the infrared spectrum below 1500 cm^-1
|
|
fingerprint region
|
|
equal to 1/wavelength, unit recorded on an infrared spectrum
|
|
wavenumber
|
|
the heaviest ion on a mass spectrum corresponding to the molecule with just one electron removed
|
|
molecular ion
|
|
the way in which a parent ion breaks down into smaller fragments
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fragmentation pattern
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an M+1 peak indicates that one of the carbon atoms in the molecule is carbon-____
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13
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____ chemistry is developing chemicals and products that are sustainable
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green
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____ principles: prevent waste, less hazardous synthesis, safer products, safer solvents, lower energy use, renewable feedstocks, reduce reagents used and number of steps, use catalysts and more selective catalysts, products designed for degradation, better process monitoring, safer processes
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12
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need to ____ with: cost of new reagents, health and safety issues of new reagents, yield, cost of new procedures (e.g. if lowering temperature increases time to reach equilibrium does it save money and energy?)
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balance
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