13 (2) - CHEMISTRY 121 Problem Set 13 Answers 1....

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Department of Chemistry University of British Columbia Problem Set 13 Answers Interaction of Light with Matter 1. What is the energy (in J) of the 3 p z state in the hydrogen atom? The answer is: -2.42 × 10 -19 J E = J 10 2.42 3 J 10 2.18 19 2 18 × = × 2. What is the wavelength (in nm) of light emitted when the electron in a hydrogen atom moves from the 5 p orbital to the 2 s orbital? The answer is: 434 nm E = -2.18 × 10 -18 J × J 10 4.579 ) 5 1 2 1 ( 19 2 2 × = E photon = 4.579 × 10 -19 J λ = J 10 4.579 ) s m 10 (3 s) J 10 (6.626 19 1 8 34 × × × × = E hc = 4.34 × 10 -7 m = 434 nm 3. The first ionization energy of cesium is 382 kJ/mol. Calculate the minimum frequency of light (in Hz) required to ionize gas phase cesium atoms in their ground electronic state. The answer is: 9.57 × 10 14 Hz The minimum frequency of light required is that which provides energy equal to the ionization energy, since any larger frequency would necessarily provide more than the ionization energy. Frequency of light = h atom one of energy ionization h photon of energy = Hz 10 9.57 s 10 9.57 s J 10 6.626 1 mol 10 6.02 mol J 10 382 14 1 14 34 1 23 1 3 × = × = × × × × = 4. He + ions are excited to the 4 s state. These ions decay to lower energy states by one or more allowed transitions, emitting light in the process. List all these possible allowed transitions, indicating the orbitals involved (for example, a transition from the 6 s to the 5 p orbital would be specified as 6 s 5 p , rather than 6 5). Which of these allowed transitions will produce the most energetic
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/03/2009 for the course ECON 210 taught by Professor James during the Spring '09 term at The University of British Columbia.

Page1 / 5

13 (2) - CHEMISTRY 121 Problem Set 13 Answers 1....

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online