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Ch.20 - Nuclear Chemistry

Chapter 20, Problem 9

How much energy in kJ/mol is released by the fission of uranium-235 to form barium-140 and krypton-93? The atomic masses are (a) 6.59 x 10^9 kJ/mol (b) 1.66 x 10^10 kJ/mol (c) 1.98 x 10^11 kJ/mol (d) 1.66 x 10^16 kJ/mol

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Hello. In this problem, we are asked to determine the energy released in killed jules from old by the fission of uranium 2 35 to produce argon 40 and tungsten 1 90 was described by the following reaction. We're told he was the following data. So we're going to begin by calculating our change in mass. So our change in mass then is going to be equal to some of the mass of our reactant minus the sum of the mass of our products. So on our reacting side then we have one neutron, we have the mass of a neutron And we have uranium 2 35. We have the massive uranium 2 35. And then we're gonna subtract off our products. So we have Argon 40. So he's a massive argon And we have Tungsten 1 90. And then we have six neutrons. So we'll take six times the massive a neutron change the mask, then Works out to 0. coming mass units. So this is our changing mass per adam. We're going to convert our mass then from atomic mass units two g. So one atomic mass unit has amassed 1.6605 times 10 to the minus 24 g. But I'm gonna convert our grams to kilograms. And so our units of atomic mass unit cancels grams cancels. So we get 1.2, 4 Times 10 to the - programs per adam. In our next step, we're then gonna calculate the energy that is released. Using the change in energy is equal to the mass times the speed of light squared. So at 1.2, 4 times 10 to the -28 kilograms for adam, we're going to round up the speed of light 23 times 10 to the eight meters per second. And that's squared. We call them that a jewel is equal to one kg meter squared second squared. We're gonna convert our jules kill jules And then we're going to make use of avocados number. So we have 6.02, 2 times 10 to the 23rd Adams and everyone more. So we have our pilgrims cancels meters squared, cancels second squared cancels. Adams cancels and jules cancels were left with killed jules per mold. So the energy then it's released Is equal to 6.72 Times 10 to the nine Kill jules per mole. If we look at the answers, provided you see that The closest answer then is a and the reason for the difference is because we rounded up the speed of light. Thanks for watching. Hope to help