icp 10/2/12 finish radioactivity. warmup 1)which particles are lightest: protons, neutrons,...

ICP

10/2/12Finish radioactivity

Warmup

1) Which particles are lightest: protons, neutrons, electrons?

2) Which particles are in the nucleus: protons, neutrons, electrons?

3) Write a nuclear symbol: 3 protons, 4 neutrons, 2 electrons

Agenda

• Fission/Fusion Notes• Finish Lab Report (Centsium) / Check

homework (Half-Life Problems)• Go over answers to Half-Life Problems

• Tomorrow: Meet in computer lab with textbook and 1st quarter test study guide.

What is fission?

http://library.thinkquest.org/17940/texts/fission/fission.html

Why does the chain reaction work?

http://library.thinkquest.org/17940/texts/fission/fission.html

C. Johannesson

F ission

• splitting a nucleus into two or more smaller nuclei

• 1 g of 235U = 3 tons of coal

U23592

Where does the energy in fission come from?

• 235U + 1 neutron 2 neutrons + 92Kr + 142Ba + ENERGY

• The energy was stored in the strong binding forces that held the uranium nucleus together.

Fission Chain Reactions

• An uncontrolled fission reaction results in a big explosion. Hiroshima!

• A controlled fission reaction will give nuclear power at a power plant.

C. Johannesson

F ission

C. Johannesson

Nuclear Power

• Fission Reactors Cooling Tower

C. Johannesson

Nuclear Power

• Fission Reactors

Fusion• Fusion occurs in the sun when four hydrogens are forced

together by the energy of high temperature and high pressure.

• 4 Hydrogens 1 Helium.• What bizarre thing happened?• The protons changed to neutrons. This change releases

energy, and this is why fusion produces energy.

Fusion

C. Johannesson

Mass Defect

• Difference between the mass of an atom and the mass of its individual particles.

4.00260 amu 4.03298 amu