--- asked in 科學化學 · 1 decade ago

急!!!化學計算題(英文)

what is the empirical formula of the compounds below?

(1) 75%carbon,25%hydrogen

(2)52.7%potassium,47.3%chlorine

要怎麼算啊??

2 Answers

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  • Anonymous
    1 decade ago
    Favorite Answer

    1. Assume there are 100 g of the compound.

    So, mass of carbon = 75 g

    Mass of hydrogen = 25 g

    Molar mass of carbon = 12.0 g/mol

    Molar mass of hydrogen = 1.0 g/mol

    By no. of mole = mass / molar mass

    No. of mole of carbon

    = 75 / 12.0

    = 6.25 mol

    No. of mole of hydrogen

    = 25 / 1.0

    = 25.0 mol

    So, molar ratio of carbon : hydrogen

    = 6.25 : 25.0

    = 1 : 4

    Therefore, the empirical formula is CH4.

    2. Assume there are 100 g of the compound

    Mass of potassium = 52.7 g

    Mass of chlorine = 47.3 g

    Molar mass of potassium = 39.1 g/mol

    Molar mass of chlorine = 35.5 g/mol

    No. of mole of potassium

    = 52.7 / 39.1

    = 1.348 mol

    No. of mole of chlorine

    = 47.3 / 35.5

    = 1.332 mol

    Molar ratio of potassium : chlorine

    = 1.348 : 1.332

    ~ 1 : 1

    So, the empirical formula is KCl.

    Source(s): Myself~~~
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  • Anonymous
    1 decade ago

    (1) 75ʲbon,25%hydrogen

    carbon, C 分子量 12  75% 12 x (25%/75%) = 4

    hydrogen, H 分子量 1 25% = 4

    所以 (1) 75ʲbon,25%hydrogen = CH4

    (2)52.7%potassium,47.3%chlorine

    potassium, 39.

    chlorine 35.5

    39 : 35.5 = 52.7% : 47.3 %

    所以 52.7%potassium,47.3%chlorine = KCl

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