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    Is there an unofficial mark scheme like this for Chemistry Unit 3 (Further Additional Chemistry)?
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    Is there a mark scheme anywhere for C3?
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    According to the above mark scheme, I'm estimating that I got about 46/60 (assuming I got 4/6 for the 6 marker. You guys think that'll be an A*? In addition, has anyone made an unofficial mark scheme for c3?
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    Does anyone know of an unofficial mark scheme for the Edexcel iGCSE C2 Chemistry June 2015 (Tuesday 9th) paper? Thanks
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    I'm a little confused on how the AQA GCSE Science Triple Award Works...I know you get the Averages of B1, C1 and P1 - Core Science, B2, C2 and P2 - Additional Science, and B3, C3 and P3 for Further Additional science.
    Do you ALSO get averages for B1, B2 and B3 - Biology, C1, C2 and C3 - for Chemistry and P1, P2 and P3 - Physics?
    Is this correct or is it JUST Core, Additional and Further Additional?
    Thanks
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    (Original post by neil20143)
    Hi I tried to make an unofficial mark scheme for this. Please be free to add things

    1a. State one conclusion about the effect of temperature on the rate of reaction? (1 mark)
    -An increase in temperature increases the rate of reaction

    aii. One reason why? (1 mark)
    -Because the volume of gas being produced at 40 degrees was more rapid than at 20 degrees.

    a(iii). Average rate (1 mark)
    -2 cm cubed per second (I think)

    1 (b) two students should the student keep constant? (2 marks)
    -Mass of Marble Chips
    -Concentration of acid

    b ii. Increasing the surface area affect the rate of reaction? (2 marks)

    -Increases the rate of reaction
    -As the particles are colliding more frequently (more successful collisions)

    c. Why does a catalyst reduce costs?
    -Because less energy is needed to start the reaction (as it has a lower activation energy)

    (there may be alternatives)

    2 (a). What could the student see? (1 mark)
    -Copper being formed (brown) or zinc disappearing

    2(b).Improves the investigation? (2 marks)
    Improvement: Use a lid/ insulate the container
    Reason: Prevents heat from being transferred to the surroundings/escaping.

    2c (6 marker - will do later at some point)

    3 (a). How does a metal conduct electricity? (4 marks)
    -Delocalised electrons can move through the metal
    -Transfer electrical charge
    -Sea of moving electrons (structure)
    -Lattice of positive ions (structure)

    3(b). Describe the structure of an alloy is different to a metal (2 marks)
    -Different elements with different sizes
    -Distort layers in the mixture, preventing them from sliding over each other.
    OR
    -Irregular pattern of atoms.

    3(c). Why is Nitinol used in braces? (1 mark)
    -Hard/strong/corrosive-resistant/smart-alloy

    3(c) (ii). Why are coins not made out of pure copper? (1 mark)
    -Because it is too soft so will corrode

    3 (c) (iii)). Aluminium Oxide

    3 (c) (iv). How can the reaction produce two different products? (1 mark)
    -Made using different reaction conditions / any specified reaction condition (e.g. pressure, temperature).
    -Using different catalysts

    3(d). Instrumental methods are used to detect impurities? (2 marks)
    Any two from:
    -They use very little samples.
    -Accurate
    -Sensitive
    -Fast

    4 (a). Why does Lithium have 7 as it's atomic number? (3 marks)
    -3 protons
    -4 neutrons
    -3 + 4 = 7 which is its mass
    -electrons have a very small mass.

    4(b). Complete the sentences (2 marks)
    -Grams
    -Carbon-12

    4(c). Isotope differences (3 marks)
    -18-Oxygen had 2 more neutrons than 16-Oxygen
    -Same number of protons
    -Same number of electrons

    5 (a). Name a soluble compound that contains silver
    (1 mark)
    -Silver Nitrate

    5(a) ii Compound containing carbonate ions (1 mark)
    -Potassium or Sodium Carbonate

    5(b) (1 mark)
    -(insoluble)Base

    5(c) (i). State how lead nitrate can be obtained from lead nitrate oxide (1 mark)
    -Crystalisation
    -Evaporate and leave to dry.

    5c(ii) (1 mark)

    Pbo + 2HNO3 = PB(NO3) + H2O

    5c (iii). number of atoms in the compound
    -9

    5(d). Empirical Formula (4 marks)
    Pb2O3


    6(a). Structure and bonding in sodium chloride (4 marks)
    -Ionic Bonding
    -Sodium atoms lose one electron to form positive ions
    -Chloride ions gain one electron to form negative ions
    -Opposites attract
    -Giant ionic structure
    -Cubic Lattice
    -Electrostatic forces

    Any of these should get the mark I think

    6(b). Other products when brine is electrolysed (2 marks)
    -Sodium Hydroxide
    -Hydrogen

    6(c). Ethical reason for not putting Iodine in food (1 mark)
    -People may not want to have these extra Iodine amount (no choice)

    6(d) (i). (2 marks)
    -3 electrons lone pairs and one covalent bond

    6(d) (ii). Why does Iodine have a low melting point (3 marks)
    -Simple molecules
    -Weak intermollecular forces
    -Little energy needed to break them down

    6(d) (iii). Why does iodine not conduct electricity? (2 marks)
    -No overall charge so can't carry electrical charge

    (I'm not sure about this question)
    iodine does not conduct elecricity because it is a simplecovalent molecule and so it does nt have ions or electrons to carry the charge
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    is this for aqa?!?!
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    What was the 6 marker?
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    Isn't there a 6 mark question on every exam
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    what was the 6 mark question? and can anyone give me a link to find the past papers for c2,b2 and p2 last summer(2015)
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    (Original post by 99sm12)
    what was the 6 mark question? and can anyone givhe me a link to find the past papers for c2,b2 and p2 last summer(2015)
    But that would be cheating.
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    (Original post by TeachChemistry)
    But that would be cheating.
    I'm just trying to test myself with more past papers( I've done all the other past papers)
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    (Original post by 99sm12)
    I'm just trying to test myself with more past papers( I've done all the other past papers)
    The 2015 series is not legitimately available. Try past papers from other boards if you are looking for more revision material.
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    (Original post by TeachChemistry)
    The 2015 series is not legitimately available. Try past papers from other boards if you are looking for more revision material.
    thanks, it should help
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    real quick question is this the aqa examboard?
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    Are these the actual questions the came up in the chemistry edexcel unit 2 GCSEs exam??
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    Can someone pls tell me what exam board this is from? Thanks- Im a bit confused
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    This is AQA (I'm 99% sure)
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    was this last years AQA one?
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    what was the 6 mark question about? (2c)
 
 
 
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