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AQA AS Chemistry Unit 2 Chemistry in Action
These were the cards I used to help me with AS Chemistry Unit 2. You can find the parallel Anki deck here: https://ankiweb.net/shared/info/886738991
160
Chemistry
12th Grade
04/23/2014

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Term
By what name is calcium silicate better known?
Definition
Slag
Term
State the meaning of the term catalyst.
Definition
Substance which speeds up a reaction but is chemically unchanged at the end
Term
Define enthalpy change.
Definition
Change in heat content at constant pressure
Term
Define enthalpy.
Definition
A measure of the heat content of a substance.
Term
Define mean bond enthalpy.
Definition
The enthalpy required to break a covalent bond, averaged over a wide range of compounds
Term
Define standard enthalpy change of combustion.
Definition
Enthalpy change when 1 mole of a substance is completely burned in oxygen with all reactants and products in standard states under standard conditions
Term
Define standard enthalpy change of formation.
Definition
Enthalpy change when 1 mole of a substance is formed from its constituent elements with all reactants and products in standard states under standard conditions.
Term
Describe a test for sulphate ions.
Definition
Add nitric/hydrochloric acid to remove carbonate ions; add barium chloride; a white precipitate of barium sulphate is produced: BaCl2(aq) + SO42-(aq) => BaSO4(s) + 2Cl-(aq)
Term
Describe conditions for the dehydration of an alcohol. What are the products?
Definition
Excess heated sulfuric acid; vapours passed over aluminium oxide at 600K. Products are an alkene and water
Term
Describe how you could use a solution of NH3 to distinguish between the solid silver halides.
Definition
AgCl dissolves in dilute ammonia; AgBr dissolves in concentrated ammonia; AgI is insoluble in concentrated ammonia
Term
Describe how you could use AgNO3 and HNO3 to distinguish between fluoride, chloride, bromide and iodide ions.
Definition
Add nitric acid to remove carbonate or hydroxide ions; add silver nitrate: =>AgF produces no precipitate; =>AgCl produces a white precipitate; =>AgBr produces a cream precipitate; =>AgI produces a pale yellow precipitate.
Term
Describe the Fehling's test for distinguishing between an aldehyde and a ketone.
Definition
Warm with Fehling's reagent (containing blue copper(ii) ions); aldehyde will reduce the ions to brick-red copper (i) ions; no observation with ketone
Term
Describe the oxidation of a primary alcohol with excess oxidising agent and reflux, giving the intermediate and the oxidising agent.
Definition
Primary alcohol => Aldehyde => Carboxylic acid. Oxidising agent is acidified potassium dichromate(vi).
Term
Describe the Tollens' test for distinguishing between an aldehyde and a ketone.
Definition
Warm with Tollens' reagent; aldehyde will reduce it to form a deposit of metallic silver; no observation with a ketone
Term
Describe the trend in reactivity with water going down group II from magnesium to radium.
Definition
Reactivity increases; magnesium reacts slowly with cold water but readily with steam; others react readily with cold water; vigour of reaction increases down the group.
Term
Explain why a catalyst has no effect on the position of an equilibrium.
Definition
It speeds up both the forward and reverse reactions, and the increase in rate is equal.
Term
Explain why a small increase in temperature has a large effect on the initial rate of a reaction.
Definition
Significant increase in the number of molecules with activation energy or above, and molecules have more kinetic energy, so there are many more successful collisions per unit time. (Beware as mark scheme will insist on a sense of scale - you must state that there are many more collisions per unit time)
Term
Explain why fluorine free radicals are not formed by the breakdown in UV light of chlorodifluoromethane, but chlorine free radicals are.
Definition
C-F bond enthalpy is too high/bond is too strong to be broken by UV light - C-Cl bond enthalpy is lower/bond is weaker
Term
Explain why the RAM value calculated from a mass spectrum may be slightly different from the value given in the periodic table.
Definition
The RAM value in the periodic table takes into account different amounts of isotopes
Term
Give a general equation for the reaction of an alkaline earth metal with water, using M as the metal.
Definition
M(s) + 2H2O(l) => M(OH)2(aq/s) + H2(g)
Term
Give a symbol equation for the reaction of chlorine with sodium hydroxide.
Definition
Cl2(g) + 2NaOH(aq) => NaClO(aq) + NaCl(aq) + H2O(l)
Term
Give a word equation for the reaction of bromoethane with potassium hydroxide in ethanol.
Definition
Bromoethane + potassium hydroxide => ethene + potassium bromide + water
Term
Give a word equation to show the reaction of 1-chloropropane with potassium cyanide.
Definition
1-chloropropane + potassium cyanide => butanenitrile + potassium chloride
Term
Give a word equation to show the reaction of bromoethane with sodium hydroxide in aqueous conditions. What type of reaction is this?
Definition
Bromoethane + sodium hydroxide => Ethanol + sodium bromide (nucleophilic substitution)
Term
Give an equation and conditions for the conversion of titanium dioxide into titanium tetrachloride. Why is this conversion necessary?
Definition
TiO2 + 2Cl2 + 2C => TiCl4 + 2CO at 900oC. TiCl4 is a liquid so it can be purified by distillation before reduction with an active metal.
Term
Give an equation and conditions for the reduction of titanium tetrachloride by sodium. What other metal can be used as a reducing agent? What are the main costs of this process?
Definition
(i) TiCl4 + 4Na => Ti + 4NaCl (ii) Argon atmosphere, 1000oC (iii) Magnesium (iv) Costs of temperature, active metal, argon, batch process
Term
Give an equation and temperature for the industrial extraction of tungsten from its ore.
Definition
WO3 + 3H2 => W + 3H2O
Term
Give an equation for the initiation reaction of the chlorination of methane.
Definition
Cl2=>2Cl.
Term
Give an equation for the reduction of manganese(IV) oxide with carbon.
Definition
MnO2 + C => Mn + CO2
Term
Give an equation to show how you can find a standard enthalpy of formation given all the standard combustion enthalpy data.
Definition
ΔH=ΣΔHc(reactants)-ΣΔHc(products)
Term
Give an equation to show how you can find the enthalpy change of a reaction given all the standard formation enthalpy data.
Definition
ΔH=ΣΔHf(products)-ΣΔHf(reactants)
Term
Give an equation to show the reaction of chlorine with water.
Definition
Cl2(g)+H2O(l)<=>HClO(aq)+HCl(aq)
Term
Give an equation to show the reaction of sodium chlorate with water.
Definition
NaClO(s)+H2O(l) <=> NaOH(aq) + HClO(aq)
Term
Give an equation to show the reaction of sodium chloride with sulphuric acid. What type of reaction is this?
Definition
NaCl(s)+ H2SO4(aq) => NaHSO4(s) + HCl(g)
Term
Give an essential  condition for an alkene to exhibit geometric isomerism.
Definition
Each of the double bond carbons must have two different groups attached (e.g. a hydrogen and an alkyl, or two alkyl groups of different lengths)
Term
Give four methods of metal extraction. What do they all involve?
Definition
Reduction with carbon; reduction by electrolysis; reduction by active metal; reduction by hydrogen. All involve reduction of the metal ions
Term
Give four reasons why metals should be recycled.
Definition
To save resources; to create less waste (e.g. from mining); to save energy resources (less energy to recycle than to extract); to reduce air pollution
Term
Give four uses of ethanol.
Definition
Used as a solvent in cosmetics; intermediate in production of other organic chemicals; fuel; alcohol
Term
Give one risk associated with the use of hydrogen gas.
Definition
It ignites easily/is explosive
Term
Give three equations for the termination reactions of the chlorination of methane.
Definition
2Cl.=>Cl2, 2.CH3=>C2H6, Cl.+.CH3=>CH3Cl
Term
Give two equations for the breakdown of ozone to oxygen catalysed by a chlorine free radical.
Definition
Cl. + O3 => ClO. + O2; ClO. + O3 => 2O2 + Cl.
Term
Give two equations for the extraction of copper from malachite (copper(II) carbonate).
Definition
CuCO3 => CuO + CO2; 2CuO + C => 2Cu + CO2
Term
Give two equations for the propagation reactions of the chlorination of methane.
Definition
Cl.+CH4=>CH3.+HCl; CH3.+Cl2=>CH3Cl+Cl.
Term
Give two equations to show the reaction of sodium bromide with an excess of sulphuric acid.
Definition
NaBr(s)+H2SO4(l) => NaHSO4(s) + HBr(g); 2HBr(g) + H2SO4(l) => SO2(g) + 2H2O(l) + Br2(l)
Term
Give two equations to show the reaction of sodium iodide with concentrated sulphuric acid.
Definition
NaI(s) + H2SO4(l) => NaHSO4(s) +HI(g); 8HI(g) + H2SO4(l) => H2S(g) + 4H2O(l) + 4I2(s)
Term
Give two half-equations to show the reaction of hydrogen bromide with sulphuric acid.
Definition
2Br- => Br2 + 2e-; 4H++SO42-+2e-=>SO2 + 2H2O
Term
Give two problems associated with the emission of sulfur oxides.
Definition
Acid rain; causes problems for people with asthma.
Term
Give two symbol equations to show the reaction of 1-fluoropropane with a concentrated solution of ammonia in ethanol.
Definition
(i) C3H7F + NH3 => C3H7NH3+ + F-; (ii) C3H7NH3+ + F- + NH3 => C3H7NH2 + NH4F
Term
How are sulfide ores converted to oxides, and what is the main environmental problem with this?
Definition
Roasting in air; sulfur dioxide produced leads to acid rain
Term
How can the sulfur dioxide produced from roasting sulfide ores be used industrially?
Definition
Manufacture of sulfuric acid
Term
How is aluminium recycled?
Definition
Collect, melt down, remould
Term
How is copper recycled? Give an ionic equation.
Definition
React scrap copper with sulphuric acid to form solutions containing Cu2+ ions, then reduce with scrap iron: Cu2+(aq) + Fe(s) => Cu(s) + Fe2+(aq)
Term
How is the blast furnace heated?
Definition
Complete combustion of carbon
Term
How many isomeric alkenes are there with the formula C5H10? Name them all.
Definition
6: pent-1-ene, Z-pent-2-ene, E-pent-2-ene, 2-methylbut-1-ene, 3-methylbut-1-ene, 2-methylbut-2-ene.
Term
If a reaction has a negative enthalpy change, is it exothermic or endothermic?
Definition
Exothermic
Term
In the electrolysis of aluminium oxide, why do the anodes need to be constantly replaced?
Definition
Elemental oxygen forms at the anode; high temperatures so carbon electrodes burn
Term
In the oxidation of alcohols, what is the oxidising agent and what is the reduction product?
Definition
Oxidising agent is acidified orange potassium dichromate(vi) (K2Cr2O7); reduction product is green chromium(iii) ions (Cr3+)
Term
In what medium is aluminium oxide electrolysed, and why?
Definition
Molten cryolite; ions must be free to move; cryolite has a lower melting point than aluminium oxide, so lower energy costs
Term
Name and outline a mechanism for the reaction of bromine with propene, and name the product.
Definition
Electrophilic addition:=> Curly arrow from double bond to Br with positive partial charge; => Curly arrow from Br-Br bond to Br with negative partial charge; (Intermediates: bromine-containing carbocation and bromide ion); => Curly arrow from lone pair on bromide ion to positive carbon; Product: 1,2-dibromopropane
Term
Name and outline the mechanism for the reaction of a haloalkane with excess ammonia, naming the types of intermediates and the types of products.
Definition
=> Curly arrow from lone pair on NH3  to δ+ carbon attached to halogen; => Curly arrow from C-X bond to δ- halogen; Intermediates: amino-containing carbocation (with positive charge on one of the hydrogens in the amino group) and halide ion. => Curly arrow from lone pair on NH3 to H+ => Curly arrow from N-H+ bond to N. Products: primary amine and ammonium halide.
Term
Name the catalyst used in the hydration of ethene.
Definition
Phosphoric acid
Term
Name the two possible products of the reaction of hydrogen bromide with propene. Which of these will be in greater abundance and why?
Definition
1-bromopropane, 2-bromopropane. 2-bromopropane is preferential because secondary carbocation intermediate is more stable than primary carbocation intermediate (due to positive inductive effect).
Term
Name two types of plastic recycling.
Definition
Mechanical and feedstock recycling
Term
Of chloride, bromide and iodide, which has the greatest reducing ability and why?
Definition
Iodide; outer electron further from nucleus with more shielding, so more easily lost
Term
On the mass spectrum of a molecule, which peak represents the molecular ion?
Definition
The furthest significant peak to the right; the tiny peak just to the right of it is due to isotopes.
Term
Other than safety, state why very high pressures are not used in the Haber process.
Definition
Less electrical pumping cost and less expensive equipment (e.g. piping)
Term
Outline the mechanism for a nucleophilic substitution reaction of a haloalkane where the nucleophile is an anion, and name the types of products.
Definition
=> Curly arrow from lone pair on nucleophile to δ+ carbon attached to halogen; => Curly arrow from C-X bond to δ- halogen. Products: alcohol or nitrile, metal halide
Term
Outline the mechanism for an elimination reaction and state the types of products.
Definition
=> Curly arrow from lone pair on OH- ion to δ+ hydrogen atom adjacent to halogen; => Curly arrow from C-H bond to C-C bond; => Curly arrow from C-X bond to δ-negative halogen. Products: alkene, water and metal halide.
Term
State a use of barium sulphate.
Definition
Used in barium meal to outline the gut in medical X-rays
Term
State a use of calcium hydroxide.
Definition
Used in agriculture to neutralize soils.
Term
State a use of ethene.
Definition
Making plastics/used to make polyethene
Term
State a use of magnesium hydroxide.
Definition
Milk of magnesia for curing indigestion and acid reflux
Term
State and explain the effect of an increase in pressure on the yield of ammonia in the Haber process.
Definition
Yield increases; there are fewer moles on the right hand side (products); the equilibrium shifts to the right to oppose the increase in pressure
Term
State and explain the effect of an increase in temperature on the yield of ammonia in the Haber process.
Definition
Yield decreases; the forward reaction is exothermic; equilibrium shifts to the left to oppose the increase in temperature/lower the temperature. (When answering equilibria questions which are three marks, these are always your three marking points. You must be specific about the change which is opposed.)
Term
State four essential conditions for fermentation.
Definition
Anaerobic; aqueous; yeast/zymase; 37oC/body temperature
Term
State Hess' Law.
Definition
The enthalpy change of a reaction is independent of the route taken.
Term
State the meaning of the term "carbon neutral".
Definition
No net carbon (dioxide) emissions to atmosphere
Term
State the meaning of the term "hydration".
Definition
The addition of water to a molecule/compound.
Term
State the meaning of the term stereoisomers.
Definition
Compounds with the same structural formula, but whose atoms are arranged differently in space.
Term
State two uses of chlorine and explain why it is used for these purposes.
Definition
Swimming pools and purification of drinking water; it reacts with water to form chloric(I) acid which kills bacteria by oxidation
Term
Suggest arguments in favour of the production of ethanol by hydration of ethene over fermentation of glucose.
Definition
=> Pure ethene produced - doesn't need to be distilled (so economically better); => Continuous process rather than batch process - can carry on going - also increases profit; => 100% atom economy/ethanol is the only product (fermentation produces CO2); => Fermentation of glucose has ethical issues as sugar cane is grown in poor countries where the land is needed for food.
Term
Suggest arguments in favour of the production of ethanol by fermentation of glucose over hydration of ethene.
Definition
=> Renewable source of glucose (so better for environment); => Carbon-neutral (so better for environment); => Lower temperatures needed as enzymes operate best at 37o (so fewer energy costs); => Does not require cracking of crude oil, which is expensive as it has high energy costs.
Term
Suggest three factors affecting which method is used for metal extraction.
Definition
Energy requirements (heat, electricity); cost of reducing agents; purity required
Term
Suggest why it is not possible to measure the enthalpy change directly for the following reaction: C(s,graphite) + 1/2O2(g)=>CO(g)
Definition
Carbon monoxide is not the only product as some complete combustion occurs.
Term
What are the conditions needed to make high density polythene?
Definition
Temperature&pressure just above rtp; Ziegler-Natta catalyst
Term
What are the conditions needed to make low-density polythene, and what is the name of the mechanism?
Definition
High temperature&pressure; free radical mechanism
Term
What are the electrodes made of in the electrolysis of aluminium oxide?
Definition
Graphite
Term
What are the features of the Maxwell-Boltzmann curve?
Definition
Starts at origin; skewed to the left; gets less steep over time on the left; gets less steep over time on the right and asymptotic to x-axis. (An examiner will insist on the initial part of the curve getting less steep over time.)
Term
What are the three isomeric products of the dehydration of butan-2-ol?
Definition
But-1-ene; E-but-2-ene; Z-but-2-ene
Term
What are the three stages of the pathway of the chlorination of methane?
Definition
Initiation reactions, propagation reactions and termination reactions
Term
What are the useful properties and uses of titanium?
Definition
Abundant, low density and corrosion resistant; strong alloys for aircraft, prosthetic limbs
Term
What are the uses of long chain CFCs?
Definition
Dry cleaning and de-greasing solvents
Term
What are the uses of short chain CFCs?
Definition
Aerosol propellants and refrigerants
Term
What conditions are used in the industrial hydration of ethene and why?
Definition
570K (compromise between yield and ROR); 6500kPa (compromise between yield and cost/ethene polymerising)
Term
What does CFC stand for?
Definition
Chlorofluorocarbon
Term
What environmental problems are associated with the destruction of the ozone layer?
Definition
Ozone protects from UV light; overexposure to UV would be harmful to plankton, the lowest organisms in the food chain in the ocean, disrupting whole ecosystems; and UV could cause skin cancer.
Term
What environmental problems are associated with the extraction of iron?
Definition
Carbon dioxide (greenhouse gas) and carbon monoxide (poisonous) produced in the blast furnace; sulfur dioxide produced by roasting sulfide ores
Term
What happens to the Maxwell-Boltzmann distribution when temperature is increased?
Definition
Peak shifts to the right and is lower; many more molecules have E>Ea
Term
What is a free radical?
Definition
An atom or molecule with an unpaired electron
Term
What is a nucleophile?
Definition
Negative ion or atom with a partial negative charge which has a lone pair that attacks areas of electron deficiency.
Term
What is a reducing agent?
Definition
A species that donates electrons in a redox reaction
Term
What is an ore?
Definition
A rock containing enough metal for extraction to be profitable
Term
What is an oxidizing agent?
Definition
A species that gains electrons in a redox reaction
Term
What is disproportionation? Give an example of a redox reaction in which disproportionation takes place.
Definition
A redox reaction where some atoms of an element are oxidised and some atoms of the same element are reduced. Examples: the reaction of chlorine with water to form chloric(I) acid and hydrochloric acid; the reaction of chlorine with sodium hydroxide to form sodium chlorate, sodium chloride and water.
Term
What is photodissociation?
Definition
When a chemical bond is broken by light energy
Term
What is the charge on a barium ion?
Definition
2+
Term
What is the charge on a calcium ion?
Definition
2+
Term
What is the charge on a carbonate ion?
Definition
2-
Term
What is the charge on a hydrogen ion?
Definition
1+
Term
What is the charge on a hydroxide ion?
Definition
1-
Term
What is the charge on a lead ion?
Definition
2+
Term
What is the charge on a lithium ion?
Definition
1+
Term
What is the charge on a magnesium ion?
Definition
2+
Term
What is the charge on a nitrate ion?
Definition
1-
Term
What is the charge on a potassium ion?
Definition
1+
Term
What is the charge on a silver ion?
Definition
1+
Term
What is the charge on a sodium ion?
Definition
1+
Term
What is the charge on a sulphate ion?
Definition
2-
Term
What is the charge on a sulphide ion?
Definition
2-
Term
What is the charge on a zinc ion?
Definition
2+
Term
What is the charge on an aluminium ion?
Definition
3+
Term
What is the charge on an ammonium ion?
Definition
1+
Term
What is the charge on an oxide ion?
Definition
2-
Term
What is the main cost of electrolysis? What is a solution to this?
Definition
Cost of generating electric current; plants built near HEP stations
Term
What is the name of the enzyme which carries out fermentation?
Definition
Zymase
Term
What is the name of the main aluminium-containing ore?
Definition
Bauxite
Term
What is the name of the main iron-containing ore?
Definition
Haematite
Term
What is the name of the main titanium-containing ore?
Definition
Rutile
Term
What is the organic product of an elimination reaction?
Definition
An alkene
Term
What is the oxidation product of a reaction of an aldehyde with Tollens' reagent?
Definition
Carboxylic acid
Term
What is the reduction product of the reaction of an aldehyde with Fehling's reagent?
Definition
Copper(I) oxide/ copper(I)ions
Term
What is the reduction product of the reaction of an aldehyde with Tollens' reagent?
Definition
Silver
Term
What is the role of the hydroxide ion in an elimination reaction?
Definition
A base
Term
What is the role of the hydroxide ion in nucleophilic substitution?
Definition
A nucleophile
Term
What is the standard enthalpy of formation of oxygen?
Definition
0 (as for all elements)
Term
What is the trend in the solubility of the hydroxides going down group II from magnesium to radium?
Definition
Increases
Term
What is the trend in the solubility of the sulfates going down group II from magnesium to radium?
Definition
Decreases
Term
What name is given to a geometric isomer which has similar chemical groups on the same side of the C=C bond?
Definition
Z-isomer
Term
What type of reaction is the chlorination of methane?
Definition
Free-radical substitution reaction
Term
What type of reaction is the dehydration of an alcohol?
Definition
Elimination
Term
When sodium halides react with excess sulphuric acid, what state are the sodium halides in?
Definition
Solid
Term
When sulfides are roasted, sulfur dioxide is produced. If this enters the atmosphere it will dissolve in rainwater to form sulfuric acid (acid rain). How do manufacturers prevent this from happening?
Definition
Sulfur dioxide is collected to stop it from entering the atmosphere, and is then used to make sulfuric acid.
Term
Which of 1-fluorobutane and 1-iodobutane is more reactive and why?
Definition
1-iodobutane; C-I bond has a lower bond enthalpy than C-F so is more easily broken; this is a more important factor than the greater polarity of the C-F bond.
Term
Which of but-1-ene and but-2-ene exhibits geometric isomerism? Explain why the other does not.
Definition
But-2-ene. In but-1-ene, the first carbon is attached to two hydrogen atoms.
Term
Which of substitution and elimination is favoured at high temperatures?
Definition
Elimination
Term
Which of substitution and elimination is favoured by primary haloalkanes?
Definition
Substitution
Term
Which of substitution and elimination is favoured by tertiary haloalkanes?
Definition
Elimination
Term
Which of substitution and elimination is favoured in aqueous conditions?
Definition
Substitution
Term
Which of substitution and elimination is favoured in ethanol?
Definition
Elimination
Term
Why are iodide ions stronger reducing agents than chloride ions?
Definition
In iodide ions, the outer electrons are further from the nucleus with more electron shielding than in chloride ions, so the attraction of the outer electrons to the nucleus is weaker.
Term
Why are tertiary alcohols not easily oxidised?
Definition
The carbon with the functional group has no hydrogen atoms attached, and C-C bonds are much harder to break than C-H bonds.
Term
Why do ketones not react with Tollens', Fehling's or Benedict's reagents?
Definition
Ketones are not reducing agents/functional carbon has no hydrogen atoms attached
Term
Why does methylbut-2-ene not exhibit geometric isomerism?
Definition
One of the double bond carbons has two methyl groups attached
Term
Why have politicians agreed to put restrictions on the use of CFCs?
Definition
In the atmosphere, they are broken down by UV light to free radicals and break down the ozone layer
Term
Why is carbon reduction not used for the extraction of titanium, tungsten and aluminium from their ores?
Definition
The metals react with carbon to form carbides
Term
Why is limestone added to the blast furnace?
Definition
To remove silicon dioxide impurities from the ore; they react to form calcium silicate (slag) which is removed from the bottom of the blast furnace
Term
Why is titanium not extracted by electrolysis?
Definition
Titanium has to be very pure to have low density and be corrosion resistant; electrolysis does not make sufficiently pure titanium to have these properties.
Term
Write an equation for the conversion of sulfur dioxide into sulfuric acid used in industry.
Definition
2SO2 + 2H2O + O2 => 2H2SO4
Term
Write an equation for the roasting of zinc sulfide in air.
Definition
2ZnS + 3O2 => 2ZnO + 2SO2
Term
Write equations for the four main redox reactions in the blast furnace.
Definition
(i) C + O2 => CO2 (ii) C + CO2 => 2CO (iii) Fe2O3 + 3CO => 2Fe + 3CO2 (iv) Fe2O3 + 3C => 2Fe + 3CO
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