The semiconductor industry manufactures integrated circuits in large vacuum chambers where the pressure is 1.0×10−10mm of hg.
(a) what fraction is this of atmospheric pressure? express your answer using two significant figures.
(b) at t = 10 ∘c, how many molecules are in a cylindrical chamber 50 cm in diameter and 50 cm tall?

(a): .

(b):  

Explanation:

Given, the pressure in the semiconductor industry which manufactures integrated circuits in large vacuum chambers,

We know,

1 mm of Hg = 133.322 Pa.

Therefore,

1 atmospheric pressure, = 101325 Pa.

Thus,

.

Now,

Volume of the cylindrical chamber is given by

Using the Ideal gas equation,

where,

Therefore,

the correct choice is a .

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