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AQA - Unit 5 - Energetics, Redox and Inorganic Chemistry watch

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    (Original post by Zakir)
    i got -51 i think for the enthalpy of solution..

    think i got 20.5ish (cant remember) for the delta G...what were the units?

    i put J k-1 mol-1

    not sure?
    for the delta G question, what was the reaction
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    (Original post by lou12)
    for the delta G question, what was the reaction
    the potassium nitrate one?

    i know i've got that wrong so im not sure...
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    (Original post by lou12)
    for the delta G question, what was the reaction
    There was one with potassium Nitrate and one with ammonia.

    What was the equation of potassium nitrate and water?
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    (Original post by Willyg11)
    There was one with potassium Nitrate and one with ammonia.

    What was the equation of potassium nitrate and water?
    that was a sneaky one, surely it was just KNO3 (s) -----> KNO3 (aq) ...? dissolving...
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    (Original post by Zakir)
    the potassium nitrate one?

    i know i've got that wrong so im not sure...
    That potassium nitrate one made me mad. I was just sat there for an age trying to figure it out, writing all over the page. It's like someone had a seizure on my paper haha...

    The sad thing is I still probably still got it wrong..
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    (Original post by MasterCress)
    That potassium nitrate one made me mad. I was just sat there for an age trying to figure it out, writing all over the page. It's like someone had a seizure on my paper haha...

    The sad thing is I still probably still got it wrong..
    yup i know...

    i think i invented some new reactions!! LOL..

    probz did get it wrong.

    but i think i got the second bit right, where is asked why the entrpoy was positive.

    what did you guys put?
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    (Original post by Willyg11)
    I think we are right as alot of my friends got that too

    Moles of Fe2+= 6 x moles of dichromate

    work out mass then just work out as a percentage of the other thing.
    I didn't do the x6 thing because I couldn't figure out the ratio :/

    I think I did moles of dichromate in a 1:1 ratio with iron and got like 0.17763 grams Fe, divided by the total mass it reacted with (0.31?) and multiplied by 100.

    Probably a pure fluke.

    (Original post by MasterCress)
    No, that's Hydrogen Sulfide (H2S)
    My bad I'm thinking of when you burn hydrogen sulphide in oxygen forming sulphur dioxide.
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    KNO3 +H2O --> HNO3 + KOH

    I think..
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    (Original post by MasterCress)
    That potassium nitrate one made me mad. I was just sat there for an age trying to figure it out, writing all over the page. It's like someone had a seizure on my paper haha...

    The sad thing is I still probably still got it wrong..

    (Original post by Kertha)
    KNO3 +H2O --> HNO3 + KOH

    I think..
    I did the exact same thing. I know I put KOH for sure but whether I put HNO3 is beyond me. Please tell me I did. Knowing me probably invented some new compound.
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    (Original post by Mikkels88)
    that was a sneaky one, surely it was just KNO3 (s) -----> KNO3 (aq) ...? dissolving...
    i put KNO3(s) +H20(l) ---> HNO3(aq) + KOH(aq) :s only one mark anyway....
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    I'm fairly sure it's just KNO3 (s) ---> K+(aq) + NO3-(aq)
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    (Original post by Kertha)
    KNO3 +H2O --> HNO3 + KOH

    I think..
    I said KNO3 ----> K+ + NO3-

    anyone agree
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    (Original post by Kertha)
    KNO3 +H2O --> HNO3 + KOH

    I think..
    Yeah, put that
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    (Original post by Kertha)
    KNO3 +H2O --> HNO3 + KOH

    I think..
    We got it wrong.

    I looked on the internet and got the same answer every time:
    '[The reaction is] simply dissolution.
    KNO3 is made out of the reaction of KOH and HNO3, a strong base and strong acid. the resulting compound, KNO3 is a "strong salt" or "strong electrolite salt", that only dissolves in water, and not reacting with it... after mixing the two (water and KNO3), you'll simply have a solution of KNO3 in water.'

    Am I the only one who found this paper hard?
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    (Original post by jamest92)
    I said KNO3 ----> K+ + NO3-

    anyone agree
    I'm sure that's pretty much it.... Both seem correct as you haven't got the H+ or OH-, but sure they'll allow it
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    (Original post by Biologyman)
    I did the exact same thing. I know I put KOH for sure but whether I put HNO3 is beyond me. Please tell me I did. Knowing me probably invented some new compound.
    erm i think all you have to do is write KNO3(S)+aq>>KNO3 (aq)
    Check out page 178 of the AQa textbook and it gives you a similar equation for dissolving ammonium nitrate.
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    (Original post by Biologyman)
    Yeah
    No H2S had a bad egg smell, SO2 is a colourless choking gas
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    (Original post by lou12)
    erm i think all you have to do is write KNO3(S)+aq>>KNO3 (aq)
    Check out page 178 of the AQa textbook and it gives you a similar equation for dissolving ammonium nitrate.
    1 mark lost
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    (Original post by Willyg11)
    1 mark lost
    Dw i lost loads of 1 markers. Stupid ionic equations
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    (Original post by Seasick Steve)
    Thank God for that. Yeah, that's what I put - almost makes up for my stupid mistake on the first question: me giving the definition of delta H formation instead of lattice enthalpy

    (Original post by Joe D)
    ... oh no... I'm gonna pretend I never read this :/
    after the myocardial infarction that just gave me... I think I'm gona GTFO of this thread now
 
 
 
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