Lecture35 - Chem 162, Lecture 35, Spring 2011 Fission...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chem 162, Lecture 35, Spring 2011 Fission Splitting of a large nucleus into two smaller nuclei having higher binding energies. U-235 is fissionable 235 92 U + 1 0 n 141 56 Ba + 92 36 Kr + 3 1 0 n 235 92 U + 1 0 n 137 52 Te + 97 40 Zr + 2 1 0 n Energy released: about 2.1 x 10 10 kJ mol Compare with combustion of methane: Energy released: 802 kJ mol Ratio: 2.1 x 10 10 802 = 2.6 x 10 7 Example: What mass of methane would have to burn in order to release the same amount of energy given off in the fission of 1.00 g of U-235? U-235 fission releases 2.1 x 10 10 kJ mol 1.00 g x 1 mol 235 g x 2.1 x 10 10 kJ mol = 8.9 x 10 7 kJ released 1
Background image of page 1

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

View Full DocumentRight Arrow Icon
Methane combustion releases 802 kJ mol . In order to release 8.9 x 10 7 kJ, we’d need a lot more than 1 mole of methane. 8.9 x 10 7 kJ x 1 mol 802 kJ x 16 g mol = 1.8 x 10 6 g CH 4 This is equivalent to 1800 kg or about 2 tons of CH 4 . Fission is a chain reaction: neutrons given off keep the reaction going by finding new nuclei for initiating fission. Subcritical: Less than 1 neutron from the fission causes another fission Critical: One neutron from fission causes one other fission. Supercritical: More than 1 neutron from fission causes other fission events. A supercritical reaction may be violently explosive.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 7

Lecture35 - Chem 162, Lecture 35, Spring 2011 Fission...

This preview shows document pages 1 - 3. Sign up to view the full document.

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