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Chemistry very difficult q

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    One method used to inflate air bags in cars is to use nitrogen produced chemically from the decomposition of
    sodium azide. The sodium formed reacts with potassium nitrate to give more nitrogen.
    2 NaN3(s)  2 Na(s) + 3 N2(g)
    10 Na(s) + 2 KNO3(s)  K2O(s) + 5 Na2O(s) + N2(g)
    a) In what ratio (by mass) must the sodium azide and potassium nitrate be mixed in order that no metallic sodium
    remains after the reaction?
    b) Calculate the total mass of the solid mixture needed to inflate a 60.0 dm3
    air bag at room temperature and
    atmospheric pressure.

    I have not yet attempted part b but on part a the ratio of moles of sodium azide to potassium nitrate when ensuring no metallic sol is left over is 5:1, so the ratio of masses is 325:101.1 which gives 101.1 ie 3.21:1 however the answer is sayin it is 1: 3.11????

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    Just quoting in Puddles the Monkey so she can move the thread if needed
    (Original post by Puddles the Monkey)
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