This preview shows page 1. Sign up to view the full content.
Unformatted text preview: a current running through the circuit.
· When smoke particles interferewith the ions, current is reduced in the circuit, and an alarm goes off. 6 Chemistry 52 Chapter 18 HALFLIFE
· The time it takes for half of any radionuclide to decay is called halflife. Some nuclides have half lives o f only seconds, while others have halflife of years.
· The rate of decay of any radionuclide fo llows the graph to the right, with each halflife reducing the amount of radionuclide to half of the previous amount. Examples: 1. Iodine131 has a halflife o f 8 days. What mass of a 40 g sample of iodine131 will remain after 24 days. 24 days x 1 halflife = 3 halflives 8 days sample remaining after 3 halflives = 40 g =5 g 8 2. How long would it take for a sample of C14 to decay fro m 20.0 g to 0.625 g? (½life o f C14=5730 y) ½ Life g 0 20.0 1 2 3 halflives x 7 4 5730 y =
1 halflife 5 6 7 Chemistry 52 Chapter 18 NUCLEAR REACTIONS
· Similar to transmutation, nuclear react ions occur when two or more smaller nuclei combine to form a larger one.
· The general form of a nuclear reaction...
View Full Document