(a) Calculate the number of grams of deuterium in a \(80,000 - L\) swimming pool, given deuterium is \(0.0150\% \) of natural hydrogen.

(b) Find the energy released in joules if this deuterium is fused via the reaction\(^2H{ + ^2}H{ \to ^3}He + n\).

(c) Could the neutrons be used to create more energy?

(d) Discuss the amount of this type of energy in a swimming pool as compared to that in, say, a gallon of gasoline, also taking into consideration that water is far more abundant.

Short Answer

Expert verified

(a) The mass of deuterium in a\(80,000 - L\)swimming pool is\(m = 1331.53\;g\).

(b) The amount of energy releases if the deuterium is fused via the reaction \(^2H{ + ^2}H{ \to ^3}He + n\)is,\(E = 3.595 \times {10^{ - 13}}J\).

(c) Yes, the neutrons can be used to create more energy if it induces a chain reaction.

(d) The energy released in a swimming pool is far more than that released in a gallon of gasoline.

Step by step solution

01

Concept Introduction

The power kept in the centre of an atom is known as nuclear energy. All stuff in the cosmos is made up of tiny particles called atoms. The centre of an atom's nucleus is typically where most of its mass is concentrated. Neutrons and protons are the two subatomic particles that make up the nucleus. Atomic bonds that hold them together carry a lot of energy.

02

Information Provided

  • Capacity of pool is:\(80,000 - L\).
  • Amount of natural hydrogen in deuterium is:\(0.0150\% \).
  • Fusion reaction of deuterium is: \(^2H{ + ^2}H{ \to ^3}He + n\).
03

Amount of deuterium

Firstly, calculate the mass of one deuterium molecule, it has a mass number of\(2\), and

dividing it with Avogadro number –

\({m_d} = \frac{M}{{{N_A}}}\)

Plugging in the values –

\({m_d} = \frac{{2{\rm{ }}g/mol}}{{6.022 \times {{10}^{23}}\;mo{l^{ - 1}}}}\)

And the result is obtained as –

\({m_d} = 3.32 \times {10^{ - 24}}g\)

The amount of water and the mass of the deuterium is known. Since the ratio of deuterium within the hydrogen inside the water is known, now calculate the number of water molecules. One water molecule has a molar mass of\(18\;g/mol\)–

\(\begin{array}{c}n = \frac{m}{M} = \frac{{8 \times {{10}^7}\;g}}{{18\;g/mol}}\\n = 4.44 \times {10^6}\;mol\end{array}\)

To get the absolute number of water molecules, we simply multiply the number of moles with Avogadro number –

\(N = 4.44 \times {10^6}\;mol \times 6.022 \times {10^{23}}\;mo{l^{ - 1}}\)

And the number of water molecules is –

\(N = 2.67 \times {10^{30}}{\rm{ }}molecules\)

Only\(0.0150\% \)of calculated water molecules is possibly having deuterium inside, so the number of deuterium will be –

\({N_d} = 0.00015 \times 2.67 \times {10^{30}}{\rm{ }}molecules\)

Which also gives –

\({N_d} = 4.01 \times {10^{26}}\)

And knowing the mass of the deuterium molecule we know that the total mass of all deuterium in whole pool will be –

\({m_{all}} = 1331.53\;g\)

Therefore, the value for mass is obtained as\(m = 1331.53\;g\).

04

Calculation for Energy

The energy release is happening due to the different total mass of nuclei before and after the nuclear reaction. Energy difference can be calculated by the free mass-energy formula –

\(E = \Delta m{c^2}\)

To get these mass differences take parent nuclei and subtract from them daughter nuclei and masses of all other by-products of the nuclear reaction. Since all atomic masses will be expressed with the unified atomic unit, remember how to convert it to \(eV\) –

\(lu = \frac{{931.5{\rm{ }}MeV}}{{{c^2}}}\)

Now analyse the reaction –

\(^2H{ + ^2}H{ \to ^3}He + n\)

Looking in the Appendix for the atomic masses the following is obtained–

\(\begin{array}{c}^2H = 2.014102{\rm{ }}u\\^4He = 4.002603{\rm{ }}u{\rm{ }}\\neutron{\rm{ }} = 1.008665{\rm{ }}u\end{array}\)

Subtracting the masses of parent and daughter nuclei, it is obtained –

\(\Delta m = \left( {{m_{{N^{14}}}} + {m_{{H^1}}} - {m_{{O^{15}}}}} \right)\)

Plugging in the values –

\(\begin{array}{c}\Delta m = \left( {2 \times 2.01355{\rm{ }}u - 3.016049{\rm{ }}u - 1.008665{\rm{ }}u} \right)\\\Delta m = 0.002412{\rm{ }}u\end{array}\)

So, from the energy relation it is obtained that –

\(\begin{array}{c}E = \Delta m{c^2}\\ = 0.002412 \cdot \frac{{931.5{\rm{ }}MeV}}{{{c^2}}} \cdot {c^2}\\E = 2.247{\rm{ }}MeV\end{array}\)

Hence, the result in joules is obtained as –

\(E = 3.595 \times {10^{ - 13}}J\)

Therefore, the energy value for the reaction is obtained as \(E = 3.595 \times {10^{ - 13}}J\).

05

More Energy Creation

In specific case neutrons could be used to have a better reaction and generate more energy, as it can induce the chain reaction, we also have a creation of deuterium, when neutron merges with hydrogen, which gives a lot of energy.

Therefore, more energy can be created.

06

Energy comparison in swimming pool and in gasoline

The gasoline would be having much more molecular weight\({C_3}{H_{18}}\), which would give less hydrogen, especially because we are comparing a full pool of water to the gallon of gasoline, which is less than\(4L\). With the pool, there is more hydrogen which later fuses.

Therefore, energy is more in swimming pool as compared to a gallon of gasoline.

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Most popular questions from this chapter

Find the radiation dose in \({\bf{Gy}}\) for: (a) A \(10 - mSv\)fluoroscopic x-ray series.

(b) \(50\,{\rm{mSv}}\) of skin exposure by an \(\alpha \) emitter.

(c) \(160\,{\rm{mSv}}\)of \({\beta ^ - }\)and \(\gamma \)rays from the \(^{40}\;{\rm{K}}\) in your body.

The naturally occurring radioactive isotope \(^{{\rm{232}}}{\rm{Th}}\) does not make good fission fuel, because it has an even number of neutrons; however, it can be bred into a suitable fuel (much as \(^{{\rm{238}}}{\rm{U}}\) is bred into\(^{239}P\)).

(a) What are Z and N for\(^{{\rm{232}}}{\rm{Th}}\)?

(b) Write the reaction equation for neutron captured by \(^{{\rm{232}}}{\rm{Th}}\) and identify the nuclide \(^AX\)produced in\(n{ + ^{232}}Th{ \to ^A}X + \gamma \).

(c) The product nucleus \({\beta ^ - }\)decays, as does its daughter. Write the decay equations for each, and identify the final nucleus.

(d) Confirm that the final nucleus has an odd number of neutrons, making it a better fission fuel.

(e) Look up the half-life of the final nucleus to see if it lives long enough to be a useful fuel.

The energy produced by the fusion of a \(1.00 - kg\) mixture of deuterium and tritium was found in Example Calculating Energy and Power from Fusion. Approximately how many kilograms would be required to supply the annual energy use in the United States?

(a) What temperature gas would have atoms moving fast enough to bring two \(^{\rm{3}}{\rm{He}}\) nuclei into contact? Note that, because both are moving, the average kinetic energy only needs to be half the electric potential energy of these doubly charged nuclei when just in contact with one another.

(b) Does this high temperature imply practical difficulties for doing this in controlled fusion?

The laser system tested for inertial confinement can produce a \(100 - kJ\) pulse only \(1.00{\rm{ }}ns\) in duration.

(a) What is the power output of the laser system during the brief pulse?

(b) How many photons are in the pulse, given their wavelength is \(1.06{\rm{ }}\mu m\)?

(c) What is the total momentum of all these photons?

(d) How does the total photon momentum compare with that of a single \(1.00{\rm{ }}MeV\) deuterium nucleus?

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