a water molecule has charges +10e and -10e, physics?

Question

where e is the charge on an electron. If the dipole moment of the molecule has a magnitude of p=6.2*10^-30 C*m, what is the seperation(a) between the two charges?

Answer 1

Even though a water molecule contains 10 electrons--you are right--10 electrons, it does not have charge +10e or -10e. It is a complicated story to explain to you in a few sentences. But please understand, that an oxygen atom has zero dipole moment since the electrons center-symmetrically revolve around the nucleus. An oxygen molecule, which contains two oxygen atoms, has zero dipole moment since the electrons are symmetric to both atoms.
An important feature of water is its polar nature. The water molecule forms an angle, with hydrogen atoms at the tips and oxygen at the vertex. Since oxygen has a higher electronegativity than hydrogen, the side of the molecule with the oxygen atom has a partial negative charge.
The O-H bonding length in water molecule is 95.84pm, or 95.84x10^(-12)m and H-O-H angle is 104.45 degree. So the virtual positive charge center is between the two H atoms, and the distance between the negative charge center (O atom) and this positive charge center is 95.84x10^(-12)m*cos(52.225degree). From this you may calculate the magnitude of the two charges.