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    3N02 (g) + H2O (l) = 2HNO3 (aq) + NO (g)

    calculate the concentration of nitric acid produced when 0.543mol of NO2 is reacted with water and the solution is made up to 250cm3

    so I understand the first part:

    0.543mol x 2/3 = 0.362mol

    but then the mark scheme goes on to say for the second mark:

    0.362mol x 1000/250 = 1.45 (moldm-3)

    so my issue is; what does the 1000/250 show, what is it an equation for (also units for each) and where did the 1000 come from in the first place?

    any help would be appreciated
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    (Original post by BarnabyIJT)
    3N02 (g) + H2O (l) = 2HNO3 (aq) + NO (g)

    calculate the concentration of nitric acid produced when 0.543mol of NO2 is reacted with water and the solution is made up to 250cm3

    so I understand the first part:

    0.543mol x 2/3 = 0.362mol

    but then the mark scheme goes on to say for the second mark:

    0.362mol x 1000/250 = 1.45 (moldm-3)

    so my issue is; what does the 1000/250 show, what is it an equation for (also units for each) and where did the 1000 come from in the first place?

    any help would be appreciated
    1000/250 scales up the moles per 250 ml into moles per litre (1000ml), which is the unit for concentration
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    (Original post by charco)
    1000/250 scales up the moles per 250 ml into moles per litre (1000ml), which is the unit for concentration
    Aha, I see so it's 1000/250 to give 4 because conc is in moldm-3 and before I only had a 1/4 of that amount (so to multiply 250cm3 by 4 gives me the litre); thank you! it evidently wasn't as complicated as I had envisaged.
 
 
 
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