F332

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  • Created by: Sabina
  • Created on: 17-04-16 14:18
What is included in ionic equations?
Only reacting particles
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How is percentage yield calculated?
Actual yield/theoretical yield x 100
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What are the two main indicators used for acid/alkali reactions?
Methyl orange and phenolphthalein
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What colour change occurs in methyl orange?
Turns from yellow to red when adding acid to alkali
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What colour change occurs in phenolphthalein?
Turns from red to colourless when adding acid to alkali
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Why can universal indicator not be used in acid-base titration?
Its colour change is too gradual
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Explain why electrons are attracted to the nucleus but not drawn into it
Electrons have fixed energies
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What is unusual about chronium's and copper's electronic configuration?
They donate one of their 4s electrons to the 3d sub-shell because they are more stable with a full or half-full d sub-shell
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What happens when metals react and form ions in terms of oxidation states?
They normally loose electrons and are oxidised to form positive ions.This increases their oxidation number
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What happens when non-metals react in terms of oxidation states?
React by gaining electrons which means they are reduced to negative ions.This decreases their oxidation number
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What is happens when metals react with dilute acid in terms of oxidisation and reduction?
Metal atom is oxidised loosing electrons and forming soluble metal ions whilst the hydrogen ions in solution are reduced, gaining electrons and forming hydrogen molecules
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What is electronegativity?
The ability to attract the bonding electrons in a covalent bond
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What is the most electronegative element in the periodic table?
Fluorine
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Describe the trend in electronegativity in the periodic table
Increases across periods and decreases down groups (excluding the noble gases)
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What causes a bond to be polar?
When electrons in a bond are not shared equally
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Why are covalent bonds in diatomic gases non-polar?
Because the atoms have equal electronegativities and so the electrons are equally attracted to both nuclei
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What causes a dipole?
The difference in electronegativities between the two atoms in a polar bond
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What is a dipole?
A difference in charge between two atoms that is caused by a shift in electron density in the bond
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What causes a bond to be more polar?
A greater difference in electronegativity
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What causes an instantaneous dipole-induced dipole?
Electrons in charged cloud are constantly moving quickly.At a moment the electrons may be more to one side making it temporarily dipole.This causes another temporary dipole in the opposite direction on a neighbouring atom..Two dipoles attracted.
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What causes a permanent dipole-permanent dipole?
The S+ and S- charges on polar molecules cause weak electrostatic forces of attraction between molecules
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Explain how the shape of a molecule affects the strength of the intermolecular forces
The longer the carbon chain the stronger the id-id forces which hold them together as there is more surface area and more electrons to interact.Also if branched they cannot pack as closely together so have fewer areas to interact
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What is the first ionisation enthalpy?
The energy needed to remove one electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions
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What affect does having a low ionisation enthalpy have?
Makes it easier to form an ion
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What three factors affect the size of the ionisation enthalpy?
1.Atomic radius 2.Nuclear charge 3.Electron shielding
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What does the graph of successive ionisation enthalpies show?
The shell structure of atoms
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Why do successive ionisation enthalpies increase within each shell?
Electrons are being removed from an increasingly positive ion, so the attraction between the nucleus and the remaining electrons increases and also there is less repulsion between the remaining electrons
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Why does first ionisation enthalpy decrease down the group?
There is less attraction between the nucleus and the outer electrons
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Why does first ionisation enthalpy increase across a period?
The number of protons are increasing which means that there is stronger nuclear attraction making it harder to remove the outer electrons
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Why is there a small drop in ionisation enthalpy between group 2 and 3?
Boron's outer electron in in 2p orbital rather than 2s,so the electron in further away from the nucleus.It is also shielded by the 1s^2 electrons and partially by 2s^2 electrons
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Why is there a small drop in ionisation enthalpy between group 5 and 6?
The repulsion between two electrons in the same orbital in oxygen and sulfur means that an electron is easier to remove
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What are halogens?
Highly reactive non-metals of group 7
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Describe the trend in boiling points in the halogens
Increases down the group, as the strength of id-id forces increases due to the increase in size and relative mass of the atom
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When is the word halide used?
To describe a negatively charged halogen ion
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Describe the trend in electronegativity
Decreases down the group as the atomic radius increases
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Describe the colour of bromine,chlorine and iodine in water and hexane
Chlorine:colourless->colourless Bromine:yellow/orange->orange/red Iodine:brown->violet
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State the colour of the precipitates formed when a halide reacts with silver ions
Chloride:white Bromide:Cream Iodide:yellow
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Explain how halogens can be extracted from a halide solution by electrolysis
When a aqueous solution containing halide ions is electrolysed the halide ions are attracted to the anode.The halide ions lose electrons to the electrode and are oxidised to atoms then combine forming molecules.At cathode hydrogen ions form H gas
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Explain why chlorine can only be extracted from a concentrated sodium chloride solution
In a sodium chloride solution there are 2 cations and 2 anions.The anion discharged depends of the conc of the solution.In dilute solution Cl- aren't discharges ,OH- is discharged instead so product at anode are H2O+O2.If conc,chlorine is produced
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What halogen cannot be produced from the electrolysis of a halide solution?
Fluorine
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Explain the problems with storing and transporting fluorine
It is the most reactive halogen and the most hazardous.Reacts with metals and non-metals so can only be stored in expensive containers lined with nickel or copper-nickel alloys
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Explain how chlorine is stored
Stored as a liquid under pressure in small cylinders
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What are the problems with storing and transporting bromine
It is a liquid at room temperature so is easier to store however is extremely volatile
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Describe what fluorine is used to make and their useful properties
PTFE:inert,low friction and thermally stable->non-stick coating on pans HCFCs:inert and gas at r.t.->refrigerant SODIUM FLUORIDE:strengthens tooth enamel->toothpaste
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Describe what chlorine is used to make and its useful properties
PVC:electrical insulator->electrical wires BLEACH:kills bacteria->water treatment
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Describe what bromine is used in
Medicines, agricultural chemicals and flame retardants
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What is iodine used in?
Medicines and is also an essential nutrient
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What are the two different production processes?
Batch and continuous
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What is continuous production?
Reactants enter the vessel and products continuously leave-reaction doesn't need to be stopped
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What are the advantages of a continuous production?
1.Lower labour costs 2.Can make large quan
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What are disadvantages of continuous production?
1.More expensive to build 2.More expensive to run unless the plant runs at full capacity
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Give some examples of continuous production
1.Making industrial ethanol 2.Haber process 3.Blast furnace
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What is batch production?
Reactants enter the vessel and react.The product is then removed,the vessel is cleaned and then the process starts again
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What are the advantages of batch production?
1.Small quantities can be made 2.The reaction vessel can be used to make other products
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What are the disadvantages of batch production?
1.More labour intensive as emptying and cleaning is required 2.Contamination can occur is cleaning is not thorough
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Give some examples of batch production
1.Dye manufacture 2.Aspirin and paracetamol manufacture 3.Steel making 4.Production of ethanol by fermentation
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Other cards in this set

Card 2

Front

How is percentage yield calculated?

Back

Actual yield/theoretical yield x 100

Card 3

Front

What are the two main indicators used for acid/alkali reactions?

Back

Preview of the front of card 3

Card 4

Front

What colour change occurs in methyl orange?

Back

Preview of the front of card 4

Card 5

Front

What colour change occurs in phenolphthalein?

Back

Preview of the front of card 5
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