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    Hello,


    I am practicing past papers and came accross this question which I am not sure of how to do it. Can anyone please help me.


    Sulphuric Acid is manufactured by a process outlined below.


    Step 1. make SO2

    Step 2. SO2+02--->SO3

    Step 3. SO3+H2SO4--->H2S2O7

    Step 4. H2S207+H20--->H2SO4


    In step 4 H2S2O7(Oleum) is reacted with water to produce sulphuric acid.

    What is the maximum mass of sulphuric acid that can be made from one tonne(i know 1000kg) of the sulphur dioxide produced in Step 1?


    (Relative atomic masses: H=1, O=16, S=32)


    The thing I don't understand is that sulphuric acid is mentioned in step 3 and 4 and sulphur dioxide in step 1. I am not sure how connect them to find the correct answer.

    Thanks for any help.


    Charikaar
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    Write down overall reaction for sulfuric acid production. At least half of the information provided in the question is here just to hide the very simple stoichiometry

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    Borek
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    (Original post by charikaar)
    Hello,


    I am practicing past papers and came accross this question which I am not sure of how to do it. Can anyone please help me.


    Sulphuric Acid is manufactured by a process outlined below.


    Step 1. make SO2

    Step 2. SO2+02--->SO3

    Step 3. SO3+H2SO4--->H2S2O7

    Step 4. H2S207+H20--->H2SO4


    In step 4 H2S2O7(Oleum) is reacted with water to produce sulphuric acid.

    What is the maximum mass of sulphuric acid that can be made from one tonne(i know 1000kg) of the sulphur dioxide produced in Step 1?


    (Relative atomic masses: H=1, O=16, S=32)


    The thing I don't understand is that sulphuric acid is mentioned in step 3 and 4 and sulphur dioxide in step 1. I am not sure how connect them to find the correct answer.

    Thanks for any help.


    Charikaar
    (First of all are you sure that step 2 is written correctly because it doesn't appear to be balanced, I would say it was :

    Step 2. 2SO2 + O2 ---> 2SO3 or Step 2. SO2+ 1/202 ---> SO3 )

    It's quite simple, the fact that sulphuric acid is needed in step 3 is irrelevant to the production of it in step 4. What is more important is to look at the reaction scheme and say for one mole of sulphur dioxide put in there is one mole of sulphuric produced

    From then onwards it is simple stoichiometry:

    So moles of SO2 = mass/RMM = 1 x 10^6 g/64 = 15625 mol

    as ratio is 1:1, mole of H2SO4 = 15625 also

    therefore max mass of H2SO4 = mol x RMM = 15625 mol x 98 g mol^-1
    = 1531250 g
    = 1531kg or about 1.5 tonnes


    hope that helped!
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    (Original post by charikaar)
    Hello,


    I am practicing past papers and came accross this question which I am not sure of how to do it. Can anyone please help me.


    Sulphuric Acid is manufactured by a process outlined below.


    Step 1. make SO2

    Step 2. SO2+02--->SO3

    Step 3. SO3+H2SO4--->H2S2O7

    Step 4. H2S207+H20--->H2SO4


    In step 4 H2S2O7(Oleum) is reacted with water to produce sulphuric acid.

    What is the maximum mass of sulphuric acid that can be made from one tonne(i know 1000kg) of the sulphur dioxide produced in Step 1?


    (Relative atomic masses: H=1, O=16, S=32)


    The thing I don't understand is that sulphuric acid is mentioned in step 3 and 4 and sulphur dioxide in step 1. I am not sure how connect them to find the correct answer.

    Thanks for any help.


    Charikaar
    Also Step four, shouldnt it be:

    H2 S2 O7 + H2 O ---> 2H2 SO4
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    (Original post by geekypoo)
    Also Step four, shouldnt it be:

    H2 S2 O7 + H2 O ---> 2H2 SO4
    You are right!


    Thank you very much for helping me out.


    Charikaar
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    well if u just work through, but really shouldnt the number of moles for all the reactions except the last one be the same, so doesnt it make half as many moles so it'd be half the answer that was stated above?
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    (Original post by geekypoo)
    well if u just work through, but really shouldnt the number of moles for all the reactions except the last one be the same, so doesnt it make half as many moles so it'd be half the answer that was stated above?


    good point. This is gcse past paper question.


    balanced steps would look like this:

    Step 1. make S+O2---> SO2

    Step 2. 2SO2+02--->2SO3

    Step 3. SO3+H2SO4--->H2S2O7

    Step 4. H2S207+H20--->2H2SO4

    there are 2 moles in step 2 and 2 moles in step 4 so the simplest whole number ratio is 1:1


    How would you do it?


    charikaar
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    I would probably put the overall reaction

    Step 1. make S+O2---> SO2

    Step 2. SO2+½02--->SO3

    Step 3. SO3+H2SO4--->H2S2O7

    Step 4. H2S207+H20--->2H2SO4

    So adding them all up and cancelling from Step 2 onwards:

    SO2 + ½O2 + H2 O --> H2 SO4

    So one mole of the SO2 would make 1 mole of the H2 SO4

    Nso2 = 1,000,000/64

    => NH2SO4 = 1,000,000/64

    So Mass = (1000,000/64) x 98 = 1531250 = 1.53 tonnes (to3sf)
 
 
 
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