1. Phase Change Chemical Reaction Type of Change Energy Released H 2 0 (g)  H 2 0 (l) Combustion of methane 40.7 kJ/mol 802 KJ/mol Comparison of Energy Change Nuclear 1.82 x 10 9 KJ/mol Nuclear Reaction The energy released is a nuclear reaction is 1000 -1 000 000 times more energy than chemical reactions Topic 2: Nuclear Reactions

2. To produce equal amounts of energy we need… Energy released through chemical reactions Energy released through nuclear reactions

3. Nuclear Reactions Nuclear energy relies on radioactive material What does radioactive mean? –A substance is radioactive if it emits energy in the form of EMR (gamma rays) or particles (alpha, beta or neutrons) Nuclear reactions are said to be ionizing because some forms of radiation and particles released can penetrate solid material and damage living cells

4. Nuclear explosions can release damaging nuclear radiation Chernobyl (1986) is the most severe nuclear accidents in our history Radioactive fallout: People were exposed to radioactive particles in the air and by eating and drinking radioactive materials in food. Children who drank milk from cows that had eaten contaminated grass went on to develop thyroid caner (radioactive iodine) Children born since 1986 are affected by a 200% increase in birth defects and a 250% increase in congenital birth deformities. The accident released radiation 200 X greater than that released by both atomic bombs dropped on Hiroshima and Nagasaki. The exclusion zone, known as “Death Valley,” has been increased from 30 to 70 km 2. No humans will ever be able to live in it again.

5. Nuclear reactions and isotopes To understand nuclear reactions, we need to first review isotopes Isotopes are elements with same atomic numbers but different atomic masses because of different # of neutrons Protons: Neutrons: Electrons: Protons: Neutrons: Electrons: Atomic mass Atomic number 6 Atomic number is equal to the number of protons and electrons 12-6 =6 Number of neutrons is mass – atomic number 6 6 14-6 =8 6

6. The mass of an isotope is not always the mass given in the data booklet! Always use the mass that is given. Step 1: Look up uranium on the periodic table We don’t use 238 as the mass! We use 235 since uranium-235 is an isotope of uranium-238

7. 614614-6=8 Oxygen-16 816-8=8 Polonium-212 84 128 + 84 = 212 The mass of an isotope is not always the mass given in the data booklet! Always use the mass that is given. 92 Uranium-238 146 + 92 = 238 2-1=1112 2 Helium-4 4-2=2

8. Types of Radiation Isotopes become unstable when the force of repulsion is greater than the nuclear force holding the nucleus together The unstable isotope will change into another substance and release energy in the form of radiation and particles We will study three types of radiation –alpha rays –beta rays –gamma rays A Geiger Counter is used to detect and measure intensity of ionizing radiation All of these are composed of high energy Which one of these has the highest frequency and lowest wavelength? –Gamma radiation

9. Unstable isotopes will disintegrate producing: –A different atom and, –A lot of energy in the form of radiation Unstable (Radioactive) Isotopes Unstable Stable Energy In equation form:

10. A Geiger counter was used to detect the radiation emitted from contaminated surfaces, including humans! March 11, 2011 - Following a major earthquake, a 15-metre tsunami disabled the power supply and cooling of three of Japan’s nuclear reactors causing the second largest nuclear accident since Chernobyl. All three cores largely melted in the first three days.

11. Type of Radiation Alpha Radiation Beta Radiation Made of 2 protons and 2 neutrons with a net charge of 2 + Gamma Radiation α Not very penetrating Description Penetrating Ability Symbol β A high speed electron More penetrating γ High energy photon with no mass or charge. Used to treat cancers. Most penetrating This is on page ___ of your data booklets 8

12. Ways to write nuclear reactions – pictures or equations A. B.

13. Atomic number and mass numbers must be equal for both reactants and products, which means nucleons (protons and neutrons) are conserved Writing nuclear reactions What do you notice about the atomic mass (nucleons) and the atomic number in the reactants and products? Atomic mass of an element is equal to the nucleons of an element: the number of protons and neutrons in a nucleus How many nucleons does potassium have?

14. Practice Problems: Find the missing nucleon in the following nuclear reactions: 1. To predict the other product, remember that nucleons are conserved, so the atomic mass and number must be the same on both sides 4 + A = 242 Z = 92 (Atomic number of uranium) Atomic mass A = 238 Atomic number 2 + Z = 94 Answer:

15. Practice Problems: Find the missing nucleon in the following nuclear reactions: 2. Remember that nucleons are conserved, so the atomic mass and number must be the same on both sides 32 + 0 = 32 Z = 15 (Atomic number of phosphorus) Atomic mass =32 A = 32 Atomic number = 15 16 + -1 = 15 Answer: Complete question 3 and 4 in your workbook

16. Practice Problems: 5. Write the nuclear equation for the alpha decay of radium-226. Decay means to break down – your reactant should result in at least 2 products! Alpha decay means that an alpha particle is produced. To predict the other product, remember that nucleons are conserved, so the atomic mass and number must be the same on both sides 226 - 4 = 222 88 – 2 = 86 (Atomic number of radon)

17. Practice Problems: 6. Write the nuclear reaction for the beta decay of polonium-210 Beta decay means that an beta particle is produced. 210 – 0 = 210 84 – -1 = 85 Watch out for this step, the atomic number is not 83!

18. Practice Problems: 7. Write the nuclear reaction for the beta and gamma decay of cesium- 144 Gamma decay means that an gamma particle is produced. 144 – 0 = 144 55 – -1 = 56 Answer to #8

19. Practice Problems: 9. Uranium-235 is a product of alpha decay. Write the equation to show the original isotope. This question asks us to work backwards and U-235 is the product not the reactant 235 + 4 = 239 92 + 2 = 94 Answer to #10 Complete the practice questions on pages 17-18 in your workbooks

20. 1,2,2,1

21. From the physics unit, nuclear fusion is when 2 smaller nuclei with high energy join to form a larger nucleus while releasing energy Nuclear fusion is what occurs in the sun and all stars Can we use nuclear fusion to produce energy? Not yet! We have plenty of deuterium (raw material for fusion) but we cannot contain the energy produced! Nuclear Fusion Where have we seen the word nuclear fusion?

22. Nuclear Fission Fission Animation Nuclear fission is the opposite of nuclear fusion because a large nucleus splits into smaller nuclei while releasing energy Nuclear fission begins when uranium is usually struck by a neutron and becomes unstable It then splits into 2 smaller nuclei and more neutrons to continue the reaction This reaction is difficult to control

23. CANDU reactor Video Great FAQ’s on CANDU reactor CANDU reactor stands for Canadian Deuterium Uranium Reactor CANDU uses energy from nuclear fission to produce electricity

24. Energy conversions in a nuclear reactor… Kinetic energy from fission products is used to heat water and produce steam which turns a turbine, spins a generator which creates electricity Energy conversions in the CANDU reactor are similar to those that occur in thermal (coal fired) power plants (Difference: original source of energy) Intranuclear potential energy (uranium)  thermal energy (heat)  Kinetic energy (turbine and generator)  Electrical Energy

25. CANDU Reactor Components Fuel: The fuel used is uranium - 235, in the form of uranium oxide pellets assembled into a fuel bundle CANDU reactors can be refueled while in operation (whereas other reactors have to be shut down) Moderator: Used to sustain fission reactions by slowing down fast moving neutrons The moderator used is heavy water (Deuterium Oxide (D 2 O)) – which is a heavier isotope of water)

26. Uranium deposits around the world (depending on year and source) Radioactive uranium and radium are found in soil and rocks. When they disintegrate, they produce another radioactive atom: radon gas.

27. CANDU Reactor Components Control Rods: Control rods also help to control the rate of fission Control rods absorbs neutrons in an emergency shut down Shielding: Shielding protects against radioactive by products of chain reaction from entering the atmosphere usually made of steel or concrete

28. Coal (non-renewable) Uranium-235 (non-renewable) Chemical potentialIntranuclear potential Combustion Nuclear fission by bombarding with a neutron Solar, chemical potential, thermal, kinetic, to electrical Intranuclear, thermal, kinetic, to electrical

29. Societal Environmental/ Ecological Benefits Economical Disadvantages Produces large amounts of energy compared to burning coal = EFFICIENT We have lots of uranium Nuclear plants cost considerably more money to build Benefits and Costs of Nuclear Fission Energy Risk of meltdown No gaseous emissions (CO 2, SO X, or particulates) Lower operating costs Thermal pollution of air and water non-renewable Nuclear materials can be used in nuclear weapons Nuclear material is radioactive Storage of used fuel/radioactive waste Things to consider Safety of people living/working near by? Renewable? Any emissions? Renewable or non-renewable:

30. Storage of nuclear waste

32. Albert Einstein Albert Einstein’s famous equation is… This is on page 8 of your data booklets This formula says that mass can be converted into energy A tiny loss in mass results in a gigantic gain in energy Energy change (_____) J Mass converted to energy (_____) kg Speed of EMR (______________)3.00 x 10 8 m/s

33. Einstein failed his University entrance exam He passed the math and science sections of the entrance exam, but failed the rest (history, languages, geography). Einstein had to go to a trade school before he retook the exam and was finally admitted to university. Did you know? Einstein had an illegitimate child In Einstein's private letters he revealed that he had an illegitimate daughter with a fellow former student Mileva Marić (whom Einstein got ideas from for his Nobel Prize and later married). Einstein never met his daughter her fate remained unknown. Einstein became estranged from his first wife, Mileva, then proposed a strange “contract” “I will receive my three meals regularly in my room… my bedroom and study are kept neat… and especially that my desk is left for my use only… you will renounce all personal relations with me insofar as they are not completely necessary for social reasons... you will stop talking to me if I request it” Einstein was a ladies' man After Einstein divorced Mileva, he soon married his cousin Elsa… Actually, Einstein considered marrying Elsa's daughter at first! Einstein won the 1921 Nobel Prize in Physics for his work on theoretical physics (photoelectric effect), not E=mc 2

34. Practice Problems: 1. In the fission of 1 mol of beryllium-8, the mass of the products is determined to be 2.29 x 10 -5 kg less than the mass of the reactants. Calculate the change in energy that corresponds to with this change in mass. (Answer: 2.06x 10 12 J) m = 2.29 x 10 -5 kg E = ? E = mc 2 E = (2.29 x 10 -5 kg)(3.00 x10 8 m/s) 2 E = 2.061 x 10 12 J 2.06 x 10 12 J Number 2 is very similar in calculations. Don’t forget that when we are calculating the energy of any nuclear reaction we use E= mc 2 and not Hess’ Law.

35. 3. Calculate the energy released by the alpha decay of radium-226. (Answer: -5.69 x 10 11 J) To calculate the change in mass we use page 8 of the data booklet to look up the mass of the products and reactants. Δm = m products - m reactants reactant products Δm = [1mol(4.00151 kg/mol) + 1mol(222.01757 kg/mol)] – 1mol(226.02540 kg/mol) Δm = -0.00632 kg We need to multiply the answer by 10 -3 since the masses are given in 10 -3 and it’s easier to multiply your final answer after. Δm = -0.00632 kg x 10 -3 Δm = -6.32 x 10 -6 kg E = mc 2 E = (-6.32 x 10 -6 kg)(3.00 x10 8 m/s) 2 E = -5.688 x 10 11 J -5.69 x 10 11 J We don’t need to write negative since it’s function is to tell us that energy is released.

36. 4. Calculate the energy released by the alpha decay of polonium-210. (Answer: -6.17 x 10 11 J) Δm = m products - m reactants reactant products Δm = [1mol(4.00151 kg/mol) + 1mol(205.9745 kg/mol)] – 1mol(209.98286 kg/mol) Δm = -0.00685 kg Don’t forget to multiply the mass by 10 -3 Δm = -0.00685 kg x 10 -3 Δm = -6.85 x 10 -6 kg E = mc 2 E = (-6.85 x 10 -6 kg)(3.00 x10 8 m/s) 2 E = -6.165 x 10 11 J -6.17 x 10 11 J

37. 5. Calculate the energy released in the following equation: (Answer: -1.67 x 10 13 J) Δm = m products - m reactants reactants products Δm = [1mol(140.91441 kg/mol) + 1mol(91.92611 kg/mol) + 3mol(1.00866 kg/mol)] – [1mol(1.00866 kg/mol) + 1mol(235.04392mkg/mol)] Δm = 235.8665 – 236.05186 Don’t forget to multiply the mass by 10 -3 Δm = -0.18608 kg x 10 -3 Δm = -1.8608 x 10 -4 kg E = mc 2 E = (-1.8608 x 10 -3 kg)(3.00 x10 8 m/s) 2 E = -1.66824 x 10 13 J -1.67 x 10 13 J Hint: Add the mass of all the products first (press Enter) and then subtract the reactants Remember, for nuclear energy released we always use E=mc 2. If we are given the change in mass, use it directly. If no mass is given, then we must calculate it FIRST using data on page 8 of the data booklet!

38. Since this is a nuclear reaction, we need to use E = mc 2. E = mc 2 E = (3.10 x 10 -28 kg)(3.00 x10 8 m/s) 2 E = 2.79 x 10 -11 J If an exponent is given, make sure the exponent of your answer matches. 2. 79

39. Δm = m products - m reactants Δm = [4mol(4.00151 kg/mol) + 2mol(0.000 549 kg/mol)] – 4mol(1.00783 kg/mol) Δm = -0.028712 kg Δm = -0.028712 kg x 10 -3 Δm = -2.8712 x 10 -5 kg E = mc 2 E = (-2.8712 x 10 -5 kg)(3.00 x10 8 m/s) 2 E = -2.58408 x 10 12 J 2.58

40. Answer: A C and D are incorrect because both fission and fusion release energy

41. Answer: D A and B are both examples of fusion because the mass of the product increases. C is an example of beta decay.