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How much positive and negative charge is there in a cup of water ? |
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Answer» SOLUTION :Mass of water in a cup can be taken approximately 250 g (which actually should havebeen given in the statement). In one molecule of water, there are 2 hydrogenatoms and 1 oxygen atom. Hence, in one molecule of water there are 2 + 8 = 10 protons and 2 + 8 = 10 ELECTRONS. Let it be x. If there are N no. of water molecules in a given mass then magnitude of its positive charge (or NEGATIVE charge) would be, Q = Nxe ... (1) If no. of moles of water molecules is \i then wehave, `mu = M/M_(0) = N/N_(A) rArr N = (MN_(A))/M_(0)`.......(2) where M = given mass of water = 250g `M_(0)` = molar mass of `H_(2)O` molecules (`2 xx` molar mass of H-atoms) + (molar mass of O-atom) = 2(1) + 16 = 18 g/mol N= TOTAL no. of water molecules `N_(A)`= Avogadro number From equation (1) and (2) `Q = (MN_(A))/M_(0).xe` `therefore Q =(250 xx 6.02 xx 10^(23) xx 10 xx 1.6 xx 10^(-19))/18` `therefore Q = 1.338 xx 10^(7)` C |
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