chapter8 - O. A. Pringle Problem 8.2 Physics 107 Of course,...

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So the charge to be placed in between is 0.299 times the charge on the electron. q e 0.299 = In terms of e, Coulombs q 4.781 10 20 × = q πε 0 R e 2.65 e e 2 4 π ⋅ε 0 R := Solve Eq. 1 for q; this is better done on paper. R 0.106 10 9 := ε 0 8.85 10 12 := e1 . 6 1 0 19 := Define parameters: where e is the charge on the proton and q is the negative charge placed in between, and I am using e to stand for the MAGNITUDE of the charge on the proton. The 2.65*e converts eV to joules Eq. 1 2.65 e ee 4 π ⋅ε 0 R 2 qe 4 π ⋅ε 0 R 2 + := So we need to solve where "repulsive" is the Coulomb energy between the two protons and "attractive" is the Coulomb energy between the negative charge and the two protons. 2.65eV repulsive attractive + := Here is another statement of the problem: The protons in the H2+ molecule are 0.106 nm apart, and the binding energy of H2+ is 2.65 eV. What negative charge must be placed halfway between two protons this distance apart to give the same binding energy?
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Unformatted text preview: O. A. Pringle Problem 8.2 Physics 107 Of course, the electrons also repel each other, but because the electrons are more spread out in space (each occupying a 1s orbital and staying as far away from each other as possible), the net energy increase due to electron-electron repulsion is less than the net energy increase due to electron-proton attraction. In H2, each electron experiences an attractive force due to two protons. This attractive force is greater than the attractive force due to the single proton in H. The energy needed to detach an electron from a hydrogen atom is 13.6 eV, but the energy needed to detach an electron from a hydrogen molecule is 15.7 eV. Why do you think the latter energy is greater. O. A. Pringle Problem 8.1 Physics 107 1...
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This note was uploaded on 02/16/2010 for the course CHEM 550 taught by Professor Abra during the Fall '09 term at Pennsylvania State University, University Park.

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