chem calculation

The composition by volume of Hong Kong town gas is approximately 49%H2,28.5%CH4,3.0%CO and 19.5%other incombustible gases.

Calculate the volume of oxygen needed to burn 100dm^3 of town gas.

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  • 1 十年前
    最愛解答

    For gases at the same temperature and pressure, volume ratio = mole ratio.

    2H2(g) + O2(g) → 2H2O(g)

    Volume ratio H2 : O2 = 2 : 1

    Volume of H2 = 100 x 49% = 49 cm3

    Volume of O2 needed = 49/2 = 24.5 cm3

    CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)

    Volume ratio CH4 : O2 = 1 : 2

    Volume of CH4 = 100 x 28.5% = 28.5 cm3

    Volume of O2 needed = 28.5 x 2 = 57 cm3

    2COg) + O2(g) → 2CO2(g)

    Volume ratio CO : O2 = 2 : 1

    Volume of CO = 100 x 3% = 3 cm3

    Volume of O2 needed = 3/2 = 1.5 cm3

    Total volume of O2 needed

    = 24.5 + 57 + 1.5

    = 83 cm3

    2007-09-07 01:57:09 補充:

    看錯了!把題目的 100 dm^3 看成了 100 cm^3。更正:以上計算中,所有單位均為 dm^3,而不是 cm^3。而最後答案是『83 dm^3』。多謝 foflinanana 君指正錯誤。

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