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(OCR Salters) AS basic Gas Volumes/Entropy question (confused) watch

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    here is a question and the solution to it. i dont however, understand the solution, so some clarification would be awesome

    What volume of gas is produced when 15g of sodium is reacted with excess water at r.t.p.?
    equation: 2Na + 2H2O -> 2NaOH + H2
    Moles of Na = 0.65mol.
    From the equation, 2 moles of Na produces 1 mole of H2
    (I understand up to here)
    So you know 0.65 moles Na produces 0.65/2 = 0.325 moles H2 ok now why did we divide 0.65 by 2? this really has me confused haha.

    any help would be much appreciated

    thanks <3
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    (Original post by dumb maths student)
    here is a question and the solution to it. i dont however, understand the solution, so some clarification would be awesome

    What volume of gas is produced when 15g of sodium is reacted with excess water at r.t.p.?
    equation: 2Na + 2H2O -> 2NaOH + H2
    Moles of Na = 0.65mol.
    From the equation, 2 moles of Na produces 1 mole of H2
    (I understand up to here)
    So you know 0.65 moles Na produces 0.65/2 = 0.325 moles H2 ok now why did we divide 0.65 by 2? this really has me confused haha.

    any help would be much appreciated

    thanks <3
    From your eqn, the only gas produced is hydrogen. and mol ratio shows that mol of H2 = 1/2 x mol of Na reacted.
 
 
 
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