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    (Original post by thomaarrss)
    did the hydrogen oxygen fuel cell have to be in any order?!! Did it say positive negative electrode because i just did whatever order?? how many marks you think ill loose?
    It definitely asked for positive electrode 1/2 eq and negative electrode 1/2 eq separately, but I don't know the specific order.

    I reckon you probably put down the correct half eq with the correct electrode (ox = negative, red = positive) but can't recall this because its such a minor ting

    If you genuinely just wrote them in any order, its 50/50 chance you got them in the right order so 1/3 if you got the overall eq right

    2/3 if youre luckyyyyyyyy and theres some sort of error carried but thats just optimism ngl
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    (Original post by emilies18)
    what do you think the grade boundaries will be like?
    isaisababy and a few others methinks came up with predicted grade boundaries, its been pasted to the bottom of the OP
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    (Original post by hi-zen-berg)
    isaisababy and a few others methinks came up with predicted grade boundaries, its been pasted to the bottom of the OP
    sorry.. whats the OP?
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    Name:  image.png
Views: 89
Size:  77.2 KBRegarding the solubility of MgCl2(s):

    The answer is in fact the solubility will increase with temperature. The question stated itself that solubility is defined as the amount of solute available to dissolve in a solvent ( in this case water ). Hence by the reverse reaction due to exothermic enthalpy of solution, more magnesium chloride will be produced, hence increasing its solubility.

    I have attached an image showing solubility (per 100g) of MgCl2, increasing in increments of 10 degrees kelvin.
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    (Original post by hi-zen-berg)
    isaisababy and a few others methinks came up with predicted grade boundaries, its been pasted to the bottom of the OP
    I reckon it will just be the same as last years paper, people always make stupid mistakes
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    (Original post by emilies18)
    sorry.. whats the OP?
    Original Post
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    (Original post by RefusedAccess)
    Name:  image.png
Views: 89
Size:  77.2 KBRegarding the solubility of MgCl2(s):

    The answer is in fact the solubility will increase with temperature. The question stated itself that solubility is defined as the amount of solute available to dissolve in a solvent ( in this case water ). Hence by the reverse reaction due to exothermic enthalpy of solution, more magnesium chloride will be produced, hence increasing its solubility.

    I have attached an image showing solubility (per 100g) of MgCl2, increasing in increments of 10 degrees kelvin.
    That's quite soliddddddd i think youre right there
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    Does anyone know what the highest grade boundaries have been before?
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    (Original post by hi-zen-berg)
    It definitely asked for positive electrode 1/2 eq and negative electrode 1/2 eq separately, but I don't know the specific order.

    I reckon you probably put down the correct half eq with the correct electrode (ox = negative, red = positive) but can't recall this because its such a minor ting

    If you genuinely just wrote them in any order, its 50/50 chance you got them in the right order so 1/3 if you got the overall eq right

    2/3 if youre luckyyyyyyyy and theres some sort of error carried but thats just optimism ngl
    ffs! just thought it was half equation1 and 2 like usual... i put hydrogen first! do you know if delta G had to be any significant figures?????
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    (Original post by vish.handa)
    I put sulfur for the first question, I'm guessing i'd still get covalent mark but was there anything that specified it be p4O10? Dont think I read it properly
    It said at the very top, this question is about period 3 from sodium to phosphorus, very cheeky
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    It said that it was looking at elements Na->P, I made that mistake at first too!
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    For marks for each question-
    1) Periodicity - 12 Marks
    2) Born-Haber Cycle - 8 Marks
    3)Enthalpy of Solution - 6 marks
    4) First EMF Q - 11 Marks
    5) Hydrogen Oxygen EMF thing - 9 marks
    6) Contact Process - 14 marks
    7) Cr questions - 12 Marks
    8) Cobalt Chemistry -12 marks
    9) Colorimetry/Purification Calculation Q - 16 Marks
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    Anyone know if for the entropy one you needed to half the values, seeing as entropy and enthalpy are per mole??? i halved but literally no one else did
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    would i still get a mark if i put p4o10 as the element identified and not P
    please someone tell me I'm really worried
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    i thouhght when calcuating delt H and delta S u would need divide by 2 am i wrong ?
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    (Original post by charanjittt)
    would i still get a mark if i put p4o10 as the element identified and not P
    please someone tell me I'm really worried
    It said ELEMENT so probably not. Also the following part said the equation with the OXIDE of the element you named so they assumed you named the element.
    You'd still get the bonding mark and equation mark provided they are right
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    (Original post by thomaarrss)
    ffs! just thought it was half equation1 and 2 like usual... i put hydrogen first! do you know if delta G had to be any significant figures?????
    i think they normally if an answer is 1.23456789 they will say "answer which rounds to 1.23" in markscheme you're probably fine there. i think ISA/EMPA and Mr is where they are picky about dp/sf
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    (Original post by mgill17)
    For marks for each question-
    1) Periodicity - 12 Marks
    2) Born-Haber Cycle - 8 Marks
    3)Enthalpy of Solution - 6 marks
    4) First EMF Q - 11 Marks
    5) Hydrogen Oxygen EMF thing - 9 marks
    6) Contact Process - 14 marks
    7) Cr questions - 12 Marks
    8) Cobalt Chemistry -12 marks
    9) Colorimetry/Purification Calculation Q - 16 Marks
    rock solid thanks
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    Can someone explain why does the E.M.F increase with pressure?
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    I think I got 87 in this and Unit 4 - any UMS predictions? Take in mind i think I got 46 in EMPA
 
 
 
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