L41-Nuclear3

L41-Nuclear3 - Energy of nuclear transformations- mass...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

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

Unformatted text preview: Energy of nuclear transformations- mass defect and Einstein mass-energy relation- star chemistry (fusion)- nuclear power (fission) Mike Hour , Grant Powers, 1946 (Combat Art Division, United States Marine Corps Water color on paper) Mass defect and energy-mass inter-conversion in nuclear transformations Nuclear transformations: mass number A and charge number Z are conserved 238 92 U -> 4 2 He + 234 90 Th A: 238 = 4 + 234 Z: 92 = 2 + 90 MASS is not conserved in nuclear rxns! It is converted to ENERGY E=mc 2 or D E= D mc 2 , where c=2.9979x10 8 m/s How to calculate energy of nuclear reactions? Consider fusion rxn (1919, Rutherford): 14 7 N + 4 2 He -> 17 8 O + 1 1 H + D E D E= S ( D E f ) products - S ( D E f ) reactants D E f : energies of formation of a nucleus from nucleons, e.g.: 8 1 n + 8 1 1 H -> 16 8 O + D E f by using E=mc 2 formula: D E f =[m( 16 8 O) 8*m( 1 1 H)-8*m( 1 n)]c 2 =-2.269x10-28 kg* c 2 =-6.8x10-12 J Formation of nuclides from neutrons and protons: exothermic Binding energy per nucleon: E b = D E f /n The following fusion rxn describes how energy is produced in Sun and many other stars: 1 H + 1 H -> 2 H + +1 e 2 H + 1 H -> 3 He + g 3 He + 1 H -> 4 He + +1 e Overall: 4 1 H -> 4 He + 2 +1 e Calculate energy released by formation of one mole of 4 He by the above rxn. Compare this energy with the energy released by burning the same amount of hydrogen The following fusion rxn describes how energy is produced in Sun and...
View Full Document

This note was uploaded on 07/22/2008 for the course CHEM 115b taught by Professor Reisler during the Spring '08 term at USC.

Page1 / 17

L41-Nuclear3 - Energy of nuclear transformations- mass...

This preview shows document pages 1 - 6. Sign up to view the full document.

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