One cubic meter of atomic hydrogen at 0°C at atmospheric pressure contains approximately 2.70 1025 atoms. The first excited state of the hydrogen atom has an energy of 10.2 eV above the lowest state, called the ground state. Use the Boltzmann factor to find the following.

(a) the number of atoms in the first excited state at 0°C
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(b) the number of atoms in the first excited state at (6.50 103)°C (Do not round the numbers in your calculation.)

Respuesta :

Answer:

(a) N = 1.159x10⁻¹⁶³ atoms

(b) N = 6.9x10¹⁷ atoms

   

Explanation:

The Boltzmann factor is the following:

[tex] N_{E} = N_{i} e^{-\frac{E}{k_{B}T}} [/tex]

where [tex]N_{E}[/tex]: is the number of atoms in the energy state E, [tex]N_{i}[/tex]: is the number of atoms in the energy ground state, [tex]k_{B}[/tex]: is the Boltzmann constant and T: is the temperature

(a) The number of atoms in the first excited state at 0°C is:  

[tex] N_{10.2 eV} = 2.70 \cdot 10^{25} \cdot e^{-\frac{10.2 eV\cdot \frac{1.602 \cdot 10^{-19} J}{1 eV}}{(1.38 \cdot 10^{-23} J/K)(273 K)}} = 1.159 \cdot 10^{-163} atoms [/tex]

The number of atoms in the first excited state at 0 °C is approximately zero.  

(b) The number of atoms in the first excited state at 6.50x10³ °C is:

[tex] N_{10.2 eV} = 2.70 \cdot 10^{25} \cdot e^{-\frac{10.2 eV\cdot \frac{1.602 \cdot 10^{-19} J}{1 eV}}{(1.38 \cdot 10^{-23} J/K)((6.50 \cdot 10^{3} + 273) K)}} = 6.9 \cdot 10^{17} atoms [/tex]        

The increasing of the temperature to 6.50x10³ °C results in an increase in the number of atoms in the first excited state to 6.9x10¹⁷ atoms.

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