(4\/2 He)+2(0\/1e)\r\n12.86 Mev\r\nyes\r\n3\r\nHe H H He\r\n2\r\n1\r\n1\r\n1\r\n1\r\n4\r\n2\r\n2019\r\nActivity B:\r\nCNO Cycle\r\nGet the Gizmo ready:\r\n\uf0b7 In the Reaction menu, select CNO cycle.\r\n\uf0b7 Select the Write equation checkbox.\r\nIntroduction: In stars larger than the Sun, the CNO cycle is the main pathway for fusion. In this\r\nreaction cycle, a heavy atom like carbon or oxygen participates in each step. At the end of one\r\ncycle, the original heavy atom has been recreated and hydrogen has been transformed into\r\nhelium. This reaction begins when temperatures reach 15,000,000 K or more.\r\nQuestion: How do large stars form helium from hydrogen through fusion?\r\n1. Observe: The Gizmo starts with an atom of carbon that reacts with the first hydrogen atom,\r\nand produces only one product. Click Fire proton to see what happens.\r\nA. What did you see?\r\nB. Turn on Write equation. In the space below and in the Gizmo, write a balanced\r\nequation for this reaction. Then, turn on Show equation to check your work.\r\n\r\n2. Predict: Click Reset. Go through the steps of the CNO cycle. Before each step, make a\r\nprediction about what the reaction will be, and type it into the Gizmo. You can use the\r\ninformation in the Gizmo to help you. As you check your answers in the Gizmo, write down\r\nthe correct reaction below. Record the energy emitted in each step as well.\r\nStep Equation Energy emitted\r\n1\r\n2\r\n3\r\n4\r\n5\r\n6\r\n(Activity B continued on next page)\r\ngamma is emitted\r\n1\r\n1\r\nH\r\n13\r\n7\r\nN\r\n1.95 Mev\r\n2.20 Mev\r\n7.54 Mev\r\n7.35 Mev\r\nH N\r\ne C\r\nH N\r\nH O\r\n1\r\n1\r\n13\r\n7\r\n0\r\n1\r\n1\r\n1\r\n1\r\n1\r\n13\r\n6\r\n14\r\n7\r\n15\r\n8\r\n2.73 Mev\r\n4.96 Mev\r\n0\r\n1\r\ne\r\n15\r\n7\r\nN\r\n1\r\n1\r\n4\r\n2\r\nH He C\r\n12\r\n6\r\n2019\r\nActivity B (continued from previous page)\r\n3. Calculate: What is the total energy emitted by the CNO cycle?\r\nHow does this value compare to the energy released in the proton-proton chain?\r\n4. Analyze: As you did with the proton-proton chain,\r\ndetermine the net equation for the CNO cycle. In\r\nthe space at right, write the equations of the CNO\r\ncycle in a column. Then, cross out any substances\r\nthat appear on both sides. Write the remaining\r\nsubstances at the bottom. This is the net equation\r\nfor the CNO cycle.\r\nA. What is the net equation for the CNO cycle?\r\nB. How does the net equation for the CNO\r\ncycle compare to the net equation for the\r\nproton-proton chain?\r\nC. How does this help explain what you observed in question 4 above?\r\n5. Interpret: A catalyst is a substance that takes part in a reaction without being consumed. In\r\nwhat ways is the carbon in the first step in the CNO cycle similar to a catalyst?\r\n_________________________________________________________________________\r\n_________________________________________________________________________\r\n6. Make a connection: Many scientists feel that fusion would be a great way to generate\r\nelectricity the future. What is the biggest obstacle to harnessing the energy of fusion?\r\n_________________________________________________________________________\r\n_________________________________________________________________________\r\nProbably due to the gamma rays that are emitted which can cause harm.\r\nThe carbon is not consumed it is transformed.\r\nIf it is the same net equation then the energy emitted should be similar.\r\n4 H-1->he-4+2e+\r\nSame.\r\n26.73\r\nsame\r\n2019\r\nActivity C:\r\nFission\r\nGet the Gizmo ready:\r\n\uf0b7 Select Fission from the Reaction menu.\r\n\uf0b7 Be sure Write equation is turned on.\r\nIntroduction: Fission is the splitting of an atom. In a fission reaction, large atoms like\r\nuranium-235 become two smaller atoms. The resulting isotopes are often radioactive, and\r\nundergo additional nuclear reactions to form a variety of products.\r\nQuestion: How does a nuclear reactor produce power?\r\n1. Observe: Click Fire neutron. Describe your observations.\r\nHow much energy was released?\r\n2. Predict: Based on what you observed, write a balanced nuclear equation. Check the Show\r\nequation checkbox to check your work. Correct your equation if needed.\r\n\r\n3. Explore: Nuclear fission does not always result in the same products. Click Reset, and then\r\nlaunch another neutron. Record your observations and repeat this process. What are the\r\nthree fission reactions modeled in this Gizmo, and how much energy does each produce?\r\nEnergy:\r\nEnergy:\r\nEnergy:\r\n4. Analyze: Are all of these nuclear equations balanced? In other words, do they all have the\r\nsame number of positive charges and same mass on both sides of the equation? Explain.\r\n_________________________________________________________________________\r\n_________________________________________________________________________\r\n(Activity C continued on next page)\r\nYes they all do .\r\n200 Mev\r\n197 Mev\r\n\r\n197 Mev\r\nThe neutron is fired and the atom splits into two and\r\nreleases several neutrons\r\n170 mev\r\n2019\r\nActivity C (continued from previous page)\r\n5. Draw connections: The uranium fission reactions are triggered by a neutron, and each\r\nreaction produces two or three more neutrons. What do you think will happen next?\r\nWhen the product of one reaction causes another reaction to start, it is called a chain\r\nreaction. In the case of nuclear fission, the number of atoms undergoing fission can multiply\r\nexponentially with the potential to release an enormous amount of energy. In a nuclear\r\npower plant, many safeguards are in place to keep the reaction under control.\r\n6. Compare: In the spaces below, list the amounts of energy released by the proton-proton\r\nchain, the CNO cycle, and nuclear fission. (For fission, list the average emitted energy.)\r\nProton-proton chain: CNO cycle: Fission:\r\nBased on these numbers, which reaction yields the most energy?\r\n7. Analyze: Fission produces a lot of energy, but it involves very heavy atoms. A uranium atom\r\nhas 235 times the mass of a hydrogen atom. A better way to compare the energy released\r\nin each reaction is to consider how much energy is release per atomic mass unit (amu). To\r\nfind this value, divide the emitted energy by the mass of the reactants in the table below.\r\nReaction Energy released Mass of reactants Energy\/amu\r\nProton-proton 4 amu (4 H-1 atoms)\r\nCNO cycle 4 amu (4 H-1 atoms)\r\nFission 235 amu (U-235)\r\nBased on this table, does fission or fusion release the most energy per amu?\r\n8. Infer: Suppose the same mass of fuel was used in a fusion reaction and a fission reaction.\r\nAbout how many times more energy would be released by the fusion reaction?\r\nShow your work:\r\nToday, nuclear power plants rely on fission. While fusion reactions have been used in\r\nnuclear bombs, many scientists and engineers hope that in the future we can use fusion to\r\nproduce energy. What are some possible advantages of fusion energy over fission energy?\r\nfusion\r\n7 times more energy\r\n6.68\r\n6.68\r\n0.8\r\n26.72\r\n26.73\r\n189\r\n189\/4=47.25 47.25\/6.68= about 7\r\nFusion energy produces more energy per amu. It is much more efficient and\r\ndoesn\u2019t take as much resources.","promotional_price":null,"promotional_time":null,"free_item":"0","price":"12.989999771118164","category_name":"GIZMOS","category_slug":"gizmos","subcategories":null}, $event)">