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A nebula's a region of the galaxy where new stars are forming contains a very tenuous gas with 128 #a t o m s##/cm^3#. This gas is heated to #7459 K# by ultraviolet radiation from nearby stars. What is the gas pressure?

Answer 1

Anna Armstrong

Pressure = #1.318\times10^{-11}" Pa"#.

Use the Ieal Gas Law to get this answer.

Instead of using the customary molar basis, we render the Ideal Gas Law on an atomic basis for this purpose:

(Pressure)#\times#(Volume) = (Boltzmann's constant)#\times#(No. of atoms)#\times#(Absolute temprerature)

Volume = #1\times10^{-6}" m"^3#

Boltzmann's constant = #1.3806\times10^{-23}" J/K"#

No. of atoms = #128#

Absolute temperature = #7459" K"#

Thus

(Pressure)#\times(1\times10^{-6}" m"^3) = (1.3806\times10^{-23}" J/K")\times(128)\times(7459" K")#

Pressure = #1.318\times10^{-11}" J/m"^3=1.318\times10^{-11}" Pa"#

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Answer 2

Audrey Arnold

The ideal gas law can be used to calculate the gas pressure as follows: [P = nRT/V] Where: - (P) is the pressure; - (n) is the number of moles of gas; - (R) is the ideal gas constant (8.314 J/(mol·K)); - (T) is the temperature in Kelvin; - (V) is the volume. Given: - (n = 128) atoms/cm³, - (T = 7459) K. The number of moles ((n)) can be calculated using Avogadro's number and the volume of the gas (which is not provided): [n = N/V] Where: - (N) is the number of atoms or molecules; once the volume is known, the gas pressure ((P)) can be calculated using the ideal gas law.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.