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(a) How much energy is released in the explosion of a fission bomb containing \(3.0 \mathrm{~kg}\) of fissionable material? Assume that \(0.10 \%\) of the mass is converted to released energy. (b) What mass of TNT would have to explode to provide the same energy release? Assume that each mole of TNT liberates \(3.4 \mathrm{MJ}\) of energy on exploding. The molecular mass of TNT is \(0.227 \mathrm{~kg} / \mathrm{mol}\). (c) For the same mass of explosive, what is the ratio of the energy released in a nuclear explosion to that released in a TNT explosion?

Short Answer

Expert verified
The fission bomb releases \(2.7 \times 10^{14}\) J. \(1.8 \times 10^7\) kg of TNT is needed for the same energy. Nuclear explosion releases \(6.0 \times 10^6\) times more energy than TNT for the same mass.

Step by step solution

01

Calculate the mass converted to energy

Given that the fissionable material has a total mass of \(3.0 \text{ kg}\) and that \(0.10\%\) of this mass is converted to energy, we first calculate this converted mass: \[\text{Converted Mass} = \frac{0.10}{100} \times 3.0 \text{ kg} = 0.003 \text{ kg}\]This is the mass that will be transformed into energy.
02

Calculate the energy released by the fission bomb

Using Einstein's mass-energy equivalence equation \(E=mc^2\), where \(c = 3 \times 10^8 \text{ m/s}\), we calculate the energy released. \[E = 0.003 \text{ kg} \times (3 \times 10^8 \text{ m/s})^2 = 2.7 \times 10^{14} \text{ Joules}\]This is the energy released by the fission bomb.
03

Calculate energy released per kilogram of TNT

One mole of TNT (\(0.227 \text{ kg/mol}\)) liberates \(3.4 \times 10^6 \text{ J}\). First, calculate the energy released per kilogram:\[\text{Energy per kg of TNT} = \frac{3.4 \times 10^6 \text{ J}}{0.227 \text{ kg/mol}} \times \frac{1}{1 \text{ kg}} \approx 1.498 \times 10^7 \text{ J/kg}\]This is the energy released by 1 kg of TNT.
04

Calculate the mass of TNT needed for the same energy release

To find the mass of TNT needed to release \(2.7 \times 10^{14} \text{ J}\), divide the total energy by the energy per kilogram of TNT:\[\text{Mass of TNT} = \frac{2.7 \times 10^{14} \text{ J}}{1.498 \times 10^7 \text{ J/kg}} \approx 1.8 \times 10^7 \text{ kg}\]Thus, approximately \(1.8 \times 10^7 \text{ kg}\) of TNT is needed to match the energy release.
05

Calculate the energy ratio for equal mass of explosive

Assume the mass of explosive is \(3.0 \text{ kg}\) for both TNT and nuclear material. Calculate the ratio of energy released: - Energy released by nuclear: \(2.7 \times 10^{14} \text{ J}\)- Energy released by TNT: \[3.0 \text{ kg} \times 1.498 \times 10^7 \text{ J/kg} = 4.494 \times 10^7 \text{ J}\]The ratio is:\[\text{Ratio} = \frac{2.7 \times 10^{14} \text{ J}}{4.494 \times 10^7 \text{ J}} \approx 6.0 \times 10^6\]So, the nuclear explosion releases about \(6.0 \times 10^6\) times more energy than TNT per equal mass.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Mass-Energy Equivalence
When Albert Einstein introduced his famous equation \(E=mc^2\), he opened the door to understanding the relationship between mass and energy. This equation tells us that mass can be converted into energy and vice versa. In simpler terms, even a small amount of mass holds a huge quantity of energy.
For instance, in the exercise, we see that only 0.10% of the 3.0 kg mass of fissionable material is converted into energy. This small fraction equates to 0.003 kg of mass being transformed. If you apply Einstein's equation, you'll see this results in an immense energy release of \(2.7 \times 10^{14}\) Joules.
To visualize, think of a tiny piece of matter holding the power to release vast amounts of energy, which is a key principle behind nuclear fission energy. This highlights why nuclear reactions are so powerful and why understanding mass-energy equivalence is crucial in harnessing this energy safely.
TNT Energy Release
TNT, or Trinitrotoluene, is a common chemical explosive used for its relatively safe handling properties and powerful energy release. When a mole of TNT explodes, it releases about 3.4 million joules (MJ) of energy. This is much less energy compared to nuclear explosions, but it's quite significant for conventional uses.
To better understand the energy released by TNT, we convert the amount of energy per mole to energy per kilogram. Since the molecular mass of TNT is 0.227 kg/mol, the energy per kilogram is approximately \(1.498 \times 10^7\) J/kg as derived in the exercise.
This calculation helps us grasp the energetic difference between nuclear and chemical reactions. Nuclear reactions, due to their mass-energy conversion, release orders of magnitude more energy than TNT for the same mass.
Energy Conversion
Energy conversion is the process of transforming one form of energy to another. In our exercise, energy is primarily converted from mass (in the case of nuclear fission) to kinetic and thermal energy. This phenomenon is what powers fission bombs, releasing massive amounts of energy.
On the flip side, when we discuss TNT, the energy conversion happens from chemical potential energy to explosive kinetic and thermal energy. This is why TNT is often used in mining and demolition, providing explosive power by converting its stored chemical energy.
The comparison drawn in the exercise shows the mass of TNT required to match a nuclear explosion's energy output. Here, you would need almost \(1.8 \times 10^7\) kg of TNT to release the same amount of energy as a mere 0.003 kg of mass lost in a nuclear reaction! This astronomical difference underscores the efficacy and sheer magnitude of energy conversion in nuclear processes, making it a vital field of study and application.

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