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Calculate the relative molecular mass of the following. (i) Ethanol (C_(2)H_(5)OH)(ii) Potassium permanganate (KMnO_(4))(iii) Potassium dichromate (K_(2)Cr_(2)O_(7))(iv) Sucrose (C_(12)H_(22)O_(11)) |
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Answer» Solution :(i) ETHANOL `(C_(2)H_(5)OH)` Molar mass = `(2 xx 12) + (6 xx 1) + (1 xx 16)` = 24 + 6+ 16 = 46 g `mol^(-1)` . (II) Potassium permanganate `(KMnO_(4))` Molar mass = 39 + 55 + `(4 xx 16)` = 39 - 55 + 64 = 158 g `mol^(-1)` . (iii) Potassium dichromate `(K_(2)Cr_(2)O_(7))` Molar mass = `(39 xx 2) + (2 xx 52) + (7 xx 16)` = 78+ 104+ 112 = 294 g `mol^(-1)` . (iv) Sucrose `(C_(12)H_(22)O_(11))` Molar mass = `(12 xx 12) + (22 xx l) + (H xx 16)` = 144 + 22 + 176 = 342 g `mol^(-1)` |
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