Gizmos Student Exploration-Nuclear Reactions Answer Key-Graded A-2024-2025 .docx, Exams of Advanced Education

Download Gizmos Student Exploration-Nuclear Reactions Answer Key-Graded A-2024-2025 .docx and more Exams Advanced Education in PDF only on Docsity! 92 1 6 Gizmos Student Exploration-Nuclear Reactions Answer Key-Graded A-2024-2025 Prior Knowledge Questions (Do these BEFORE using the Gizmo.) The chart below gives the isotope name, element name, number of protons, and number of neutrons of three isotopes. Isotope Protons Neutrons Hydrogen-1 1 0 Carbon-12 6 6 Uranium-235 92 143 1. What do you notice about the isotope number and the sum of protons and neutrons? 2. The element symbol for uranium-238 is 238 U. This means U-238 has a total mass of 238 and contains 92 protons. Write the element symbols for the isotopes in the table: Hydrogen-1 1 Carbon-12 12 Uranium- 235 235 92 Gizmo Warm-up The Nuclear Reactions Gizmo simulates a particle accelerator. Particle accelerators speed up atoms to very high velocities, then crash the atoms together with enough energy to cause changes called nuclear reactions. There are three particle beams available in this Gizmo, protons, neutrons, and helium-3 nuclei. 1. Click Fire Proton to engage the first particle beam. What happens? 2. Colliding particles don’t always react. Click Reset, and then click Fire neutron. A. Does a reaction occur? H C U The isotope number is equal to the sum of protons and neutrons. The proton joins the nucleus. No B. Explain: The neutron traveled through the nucleus. B. Emitted energy is reported in megaelectron volts (MeV), where one MeV is equal to one million electron volts. How much energy is emitted in this reaction? 3. Hypothesize : Click Next. In the next step, another proton will be fired at the hydrogen-2 atom. Make a prediction about what will happen by filling in the equation in the Gizmo and below, and then click Fire proton.(Double click the image below to open in Google Draw. Use the Text Box tool to fill in the boxes) A. Turn on Show equation. Was your predicted equation correct? B. Correct your equation if necessary. How much energy was emitted? 4. Apply : Click Next. The last step in this cycle involves two helium-3 atoms reacting. Click Fire He-3. Observe what happens, and then write an equation to describe this process. (Double click the image below to open in Google Draw. Use the Text Box tool to fill in the boxes) A. Turn on Show equation. Was your predicted equation correct? B. Correct your equation if necessary. How much energy was emitted? 5. Calculate : To find the total energy emitted in the proton-proton chain, you have to consider the fact that two He-3 atoms must be created to form the final He-4 atom. Write the energy produced in each step, and then find the sum of all of these energies using the table below. First step (H-2 created) Second step (He-3 created) Last step (He-4 created) Total energy First He-3 atom 1.44 MeV 5.49 MeV 12.89 MeV 26.72 MeV 1.44 MeV yes 5.49 MeV yes 12.86 MeV Second He- 3 atom 1.44 MeV 5.49 MeV 6. Extend your thinking : To determine the net equation for the conversion of hydrogen-1 to helium-4, list the equations for each step of the proton-proton chain in the space below. (Write two equations for the first step and the second step, because these are repeated.) Next, cross out any elements that appear on both sides of the equation. Anything that remains makes up the net equation. Introduction: Fission is the splitting of an atom. In a fission reaction, large atoms like uranium-235 become two smaller atoms. The resulting isotopes are often radioactive, and undergo additional nuclear reactions to form a variety of products. Question: How does a nuclear reactor produce power? 1. Observe : Click Fire neutron. Describe your observations. How much energy was released? 197 MeV 2. Predict : Based on what you observed, write a balanced nuclear equation. Check the Show equation checkbox to check your work. Correct your equation if needed.(Double click the image below to open in Google Draw. Use the Text Box tool to fill in the boxes) 3. Explore : Nuclear fission does not always result in the same products. Click Reset, and then launch another neutron. Record your observations and repeat this process. What are the three fission reactions modeled in this Gizmo, and how much energy does each produce? (Double click the image below to open in Google 1 1 H + 1 H → 2 H + 0 e+ 1 1 1 1 2 H + 1 H → 3 H + 1 H + 1 H 1 1 11 1 1 H + 1 H → 2 H + 0 e 1 1 1 1 2 H + 1 H → 3 H + 1 H + 1 H 1 1 11 The neutron hits the nucleus. Uranium split into 2 smaller atoms. by the mass of the reactants in the table below. Reaction Energy released Mass of reactants Energy/amu Proton-proton 26.72 MeV 4 amu (4 H-1 atoms) 6.68 amu CNO cycle 26.73 MeV 4 amu (4 H1 atoms) 6.6825 amu Fission 189 MeV 235 amu (U-235) 0.8043 amu Based on this table, does fission or fusion release the most energy per amu? fusion 8. Infer : Suppose the same mass of fuel was used in a fusion reaction and a fission reaction. About how many times more energy would be released by the fusion reaction? Today, nuclear power plants rely on fission. While fusion reactions have been used in nuclear bombs, many scientists and engineers hope that in the future we can use fusion to produce energy. What are some possible advantages of fusion energy over fission energy? 4 times Fusion creates more power which could then be cheaper and reach more people.