Question

Integrated circuits are manufactured in vacuum chambers in which the air pressure is 8.00×10−11 mmofHgmmofHg . You may want to review (Pages 549 - 550) .

Part A What is the number density? Assume TTT = 22.0 ∘C∘C. SubmitRequest Answer Part B What is the mean free path of a molecule?

Answer 1

Part A

first, convert the given pressure to Pa

P = 8e-11 * 101325 / 760

P = 1.0665e-8 Pa

Now,

PV = nRT

n / V = P / RT

n/V = 1.0665e-8 / 8.314 * 295

n/V = 4.348e-12 moles / m³

Now,

1 mole = 6.022e23 molecules

so,

number density = 6.022e23 * 4.348e-12

number density = 2.62e12 / m³

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part B

mean free path = 1/(4 * sqrt(2) * Pi * number density * (r²))

where r = 1e-10 m

so,

mean free path = 1/(4 * sqrt(2)*Pi * 2.62e12* 1e-10²))

mean free path = 2.15e6 m