In intergalactic space, there is an average of about one hydrogen atom per \(\mathrm{cm}^{3}\) and the temperature is \(3 \mathrm{K}\) What is the absolute pressure?

Short Answer

Expert verified
Answer: The approximate absolute pressure in intergalactic space is 4.14 x 10⁻¹⁸ Pa.

Step by step solution

01

Data given in the question

We are given the following data: - Average density of hydrogen atoms: 1 atom/\(\mathrm{cm}^{3}\) - Temperature: \(3 \mathrm{K}\) We will use the ideal gas law to calculate the absolute pressure.
02

Ideal gas law and constants

The ideal gas law can be expressed as: \(P V = n R T\) where \(P\) - Pressure (in Pascals) \(V\) - Volume (in cubic meters) \(n\) - number of moles of gas \(R\) - Ideal gas constant (\(8.314 \mathrm{J\, mol^{-1} K^{-1}}\)) \(T\) - Temperature (in Kelvin) Also, we need to recall: - Avogadro's number: \(N_A = 6.022 \times 10^{23}\, \mathrm{atoms/mol}\) - Boltzmann's constant: \(k_B = 1.38 \times 10^{-23}\, \mathrm{J/K}\) The pressure we want to find is: \(P = \frac{n R T}{V} = \frac{N k_B T}{V' * V}\) where \(N\) - number of hydrogen atoms per unit volume \(V'\) - Volume of unit hydrogen atom \(V\) - total volume of the space
03

Number of hydrogen atoms per cm³

We are given that there is one hydrogen atom per cm³. Hence, the number of hydrogen atoms per unit volume is: \(N = \frac{1\, \mathrm{atom}}{\mathrm{cm}^{3}}\).
04

Convert volume to meters³

It's important to note that all units in the formula should be in SI (International System) units. So, we need to convert volume from cubic centimeters to cubic meters: \(V' = \frac{1\, \mathrm{cm}^3}{10^6} = 10^{-6}\, \mathrm{m}^3\)
05

Apply the formula for pressure

Now we can use the ideal gas law to calculate the absolute pressure in intergalactic space: \(P = \frac{N k_B T}{V' * V} = \frac{1\, \mathrm{atom/cm^3} \cdot 1.38 \times 10^{-23}\, \mathrm{J/K} \cdot 3 \mathrm{K}}{10^{-6}\, \mathrm{m^3}}\) \(P = 4.14 \times 10^{-18} \, \mathrm{Pa}\) In intergalactic space, the absolute pressure is approximately \(4.14 \times 10^{-18}\, \mathrm{Pa}\).

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