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• Explain how the rate of reaction between a solid and a liquid is altered by changing the size of the pieces of solid and by changing the temperature of the liquid.

  smaller pieces of solid:

  • of same mass
  • larger surface area
  • so more frequent collisions
  • higher rate of reaction
  • higher temperature - particles move faster
  • more frequent collisions + particles have more energy
  • more collisions have required energy to react / activation energy
  • more collisions successful
  • higher rate of reaction
• Explain the similarities and differences in the way sodium and potassium react with cold water by considering their reactions and their electronic configurations.

  similarities

  • both in the same group/group 1/alkali metal

  • react in a similar way

  • same number of outer electrons/one outer

  electron

  • both produce hydrogen/fizz (when reacted with

  water)

  • both produce hydroxide/alkaline solution (when

  reacted with water)

  differences

  • potassium more reactive

  • potassium catches on fire/lilac flame

  • potassium outer electron further from nucleus

  • potassium has more shells

  • potassium has more shielding

  • potassium has less attraction of outer electron

  by nucleus

  • potassium outer electron more easily lost
• Which elements are in Group 1 of the periodic table?

  Lithium, sodium, and potassium
• What pattern do alkali metals show in their reactivity with water?

  Reactivity increases down the group
• What are the observable reactions of alkali metals with water?

  • Effervescence (fizzing/bubbles)
  • Float on surface
  • Move around
  • Produce hydrogen gas
  • Form an alkaline metal hydroxide solution
  • Get smaller, disappear, or dissolve
• How does potassium's reactivity compare to sodium and lithium?

  Potassium effervesces and moves faster
• What happens to sodium and potassium when they react with water?

  They melt into a silver-colored ball
• What color flame does potassium produce when reacting?

  Lilac flame
• What color flame does sodium produce when reacting?

  Yellow flame
• What happens to Universal Indicator when added to water after alkali metal reaction?

  Turns blue or purple
• How do group 1 metals react with water?

  By losing one electron
• Why is it easier for alkali metals to lose an electron as atomic number increases?

  Electrons are further from the nucleus
• What happens to the atomic radius of alkali metals down the group?

  It increases
• What effect does increasing atomic number have on electron shielding?

  More shielding occurs with increasing atomic number
• How does the attraction between the nucleus and outer electron change down the group?

  Attraction decreases with increasing atomic number
• What are the key factors affecting the reactivity of alkali metals?

  • Increasing atomic number
  • Greater distance of outer electron from nucleus
  • More electron shells
  • Increased electron shielding
  • Decreased attraction between nucleus and outer electron
• The order of reactivity of chlorine, bromine and iodine can be determined by carrying out displacement reactions.

  Explain how displacement reactions can be used to show the reactivity of these three elements

  • order of reactivity: chlorine > bromine > iodine

  • add (aqueous) chlorine to a solution of potassium bromide

  • the solution turns orange

  • bromine is produced: Cl2 + 2KBr → Br2 + 2KCl

  • (so) chlorine is more reactive and displaces bromine

  • add (aqueous) bromine to a solution of potassium iodide

  • the solution turns yellow/red/ brown

  • iodine is produced: Br2 + 2KI → I2 + 2KBr

  • (so) bromine is more reactive than/displaces iodine/ oxidises

  iodide ions

  • add (aqueous) chlorine to a solution of potassium iodide

  • the solution turns yellow/red/ brown

  • iodine is produced / Cl2 + 2KI → I2 + 2KCl / Cl2 + 2I-

  → I2 + 2Cl-

  • (so) chlorine is more reactive as displaces iodine

  iodide ions
• Explain how the petrol and bitumen fractions differ in their properties and uses.

  properties

   petrol has shorter (carbon) chains /ORA

   petrol has lower {melting point / boiling point} / ORA

   petrol has lower viscosity / ORA

   petrol {ignites / burns} more easily / ORA

   bitumen does not combust completely (due to high

  number of carbon atoms per molecule)

   burning bitumen produces lots of carbon monoxide/soot

  uses of petrol fraction

   fuels in cars / in motorbikes / transportation

  uses of bitumen fraction

   used for road (surfacing)

   used for roofing / flooring
• Evaluate the advantages and disadvantages of using bioethanol, instead of petrol, as a fuel for cars.

  Advantages of bioethanol

  • is renewable / petrol is finite

  • crops to make bioethanol regrown quickly

  • use reduces demand on fossil fuels

  • carbon dioxide is removed from air when growing crops (which

  are used in ethanol production)

  • may be sulfur impurities in petrol, none in ethanol / ethanol is

  less polluting than petrol (does not produce sulphur dioxide )

  • ethanol burns more completely, petrol does not

  Disadvantages of bioethanol

  • less readily available than petrol / fewer filling stations than for

  petrol (in UK but not in some countries)

  • lots of crops needed to generate sufficient fuel to replace petrol

  • less farmland available for growing food crops

  • currently few cars are built to run on bioethanolbioethanol fuel

  (in cars) runs out faster / over shorter distances / less energy

  efficient
• Explain how incomplete combustion occurs and the problems it can cause.

  Production

  • lack of / insufficient oxygen

  • {blocked burner jets / poor servicing} leads to lack of oxygen

  • poor ventilation leads to lack of oxygen

  • complete combustion cannot take place

  Product

  • produces carbon / soot

  • produces carbon monoxide

  Effects

  • wastes fuel

  • soot stains / damages decorations etc

  • soot causes health problems

  • soot may block gas jets

  • carbon monoxide is toxic

  • combines with haemoglobin / forms carboxyhaemoglobin

  • prevents blood carrying oxygen

  • no oxygen reaches cells / no respiration / death
• Evaluate the advantages and disadvantages of using hydrogen rather than petrol as a fuel for cars.

  Advantages

  • plenty of water / raw material

  • limited supplies of crude oil

  • hydrogen produces only water as waste

  • petrol produces carbon dioxide

  • carbon dioxide (emissions) may cause global warming

  Disadvantages

  • hydrogen has to be produced

  • requires energy / electricity to produce it

  • producing electricity from non-renewable sources produces

  carbon dioxide

  • expensive to produce

  • problems of storage of large volumes of flammable gas

  • stronger / heavier / bigger tanks needed

  • hydrogen a gas, petrol a liquid, hydrogen leaks more likely

  • limited outlets / conversion costs

  • shorter distance between refuelling
• Describe the advantages and disadvantages of using bio-methane rather than natural gas as a source of energy.

  advantages

  • renewable / sustainable

  • more plants can be grown

  • crops use up carbon dioxide and produce oxygen

  when growing /photosynthesising

  • carbon neutral because the carbon produced during

  combustion is used when growing the plants

  • does not use up crude oil/non-renewable resources

  disadvantages

  • crops grown for bio-fuels use up land

  • land could otherwise be used to provide homes / less

  farmland available for growing food crops

  • lots of crops required to provide a small amount of

  bio-methane

  • bad season reduces availability

  • carbon emissions due to transport and production if

  qualified
• Explain, using appropriate monomers from Figure 12, how different polymers can be formed.

  polymer molecules are long chains

  • made up of simple repeating units

  • use chloroethene (only)

  • to form poly(chloroethene)

  • which is addition polymerisation

  • use ethane-1,2-diol and ethanedioic acid

  • to form a polyester

  • which is condensation polymerisation

  • one of the bonds in the double bond in chloroethene molecule

  breaks

  molecule

  • equation

  • and chloroethene molecules join together to form a long chain

  • identification of repeat unit

  • alcohol group combines with a carboxylic acid group

  • and an ester (link) formed

  • with a water (molecule) eliminated

  • equation

  • ester link shown

  • identification of repeat unit
• Explain how poly(propene) molecules are formed from propene molecules and relate the properties of poly(propene) to its uses.

  Making the polymer

  many propene molecules

  join/react together

  form a long chain

  polymerisation reaction

  propene is the monomer

  propene is unsaturated / has a double bond

  poly(propene) has single bonds

  propene is a gas and forms poly(propene) which is a solid

  the C=C bond breaks / opens up

  Properties of poly(propene) with related uses

  property – flexible, low density (lightweight), shatterproof, high

  softening point, non-toxic, strong, tough, good insulator, water

  proof, resistant to corrosion, long lasting, can be moulded into

  shape, can be made into fibres

  Uses of poly(propene)

  use – to make plastic bags, packaging, buckets, bowls, food

  containers, ropes, carpets bottles, bottle caps, laboratory equipment, medical equipment, pipes, car bumpers, crates, furniture, tubing
• Explain the properties required of a good fuel.

  Burning considerations

  • ignite easily

  • burn easily

  • release a lot of /sufficient heat energy when it

  is burnt

  Usage considerations

  • be safe to use

  • be safe/easy to transport

  • be {safe/easy/convenient} to store

  • be reasonably cheap

  Supply considerations

  • readily available/good supply

  • be renewable/sustainable/not finite

  Products considerations

  • not produce (much) solid/ash when burnt

  • not produce much/any smoke

  • contain little/no sulfur

  • not produce {toxic/harmful} gases/fumes

  • carbon neutral

  • not produce too much carbon dioxide or other

  named gas such as sulfur dioxide or greenhouse

  gases
• Magnesium has an electronic configuration of 2.8.2.

  Oxygen has an electronic configuration of 2.6.

  Explain, in terms of their electronic configurations, how magnesium and oxygen atoms react to form the ionic compound magnesium oxide, MgO, and include a description of the structure of solid magnesium oxide

  ion formation

  • magnesium atoms lose electrons

  • each magnesium atom loses two electrons

  • to acquire full outer shell

  • magnesium (configuration) becomes 2.8

  • forms Mg2+ ion

  • electrons transferred to oxygen atoms

  • oxygen atoms gain electrons

  • each oxygen atom gains two electrons

  • oxygen (configuration) becomes 2.8

  • to acquire full outer shell

  • forms O2- ion

  structure

  • magnesium ions attract oxide ions

  • due to opposite charges

  • ions pack close together

  • ratio of ions 1: 1

  • ions arranged in lattice

  • giant (ionic) (structure)
• Explain these results by referring to the structures of the substances.

  For a sample to conduct electricity

  • charged particles must be present

  • they must be free to move

  water does not conduct because it

  • is (simple molecular) covalent

  • exists as molecules

  • contains no/(very few) charged particles

  solid sodium chloride does not conduct because

  • although it contains ions / cations / anions

  • which are charged particles

  • they are not free to move

  • because they are held together

  • by strong

  • electrostatic forces/ ionic bonds

  • in lattice

  sodium chloride solution conducts because

  • ions / cations / anions are present

  • which are charged particles

  • they are free to move

  • because the water has cut down the forces between the ions

  • ions have separated

  • move to electrode of opposite charge
• test for cations

  • flame test

  • if the flame is yellow/not lilac, sodium ions are present

  • if the flame is lilac/not yellow, potassium ions are present
• test for iodide ions

  test for iodide ions

  • make a solution of the crystals in water

  • add dilute nitric acid

  • add silver nitrate solution

  • if there is a yellow precipitate, iodide ions are present

  • if there is no precipitate, sulfate ions are present

  • Ag+ + I¯

  → AgI

  OR

  • make a solution of the crystals in water

  • add chlorine water

  • then cyclohexane

  • if the cyclohexane/top layer turns purple, iodide ions

  were present

  • if there is no colour change, sulfate ions are present

  • Cl2 + 2I-

  → 2Cl- + I2
• test for sulfate ions

  • make a solution of the crystals in water

  • add dilute {hydrochloric/nitric} acid

  • add barium {chloride/nitrate} solution

  • if there is a white precipitate, sulfate ions are present

  • if there is no precipitate, iodide ions are present

  • Ba2+ + SO4 2-→ BaSO4
• Describe tests that you should carry out on each sample to identify the type of water in each sample.

  soft

   add soap (solution)

   shake/ mix

   lather (immediately)

   no scum/ no precipitate

  permanent hard

   add soap (solution)

   shake

   no lather / less than with soft water

   scum/ precipitate

   boiled sample

   same results / boiling does not change

   becomes soft after ion exchange but not after boiling

  temporary hard

   add soap (solution)

   shake

   no lather / less than with soft water

   scum/ precipitate

   boiled sample

   after boiling precipitate / (lime)scale formed

   lather (immediately)