The lowest pressure attainable using the best available vacuum techniques is about 10^−12 n/m^2.

at such a pressure, how many molecules are there per cm^3 at 19 °c?

247 molecules

Explanation:

This problem can be solved by using the ideal gas equation:

where in this case we have

is the lowest pressure attainable

is the volume we are considering

n is the number of moles

R is the gas constant

is the absolute temperature

Solving the equation for n, we find

And since the number of molecules in 1 mole of gas is

(avogadro number)

The number of molecules present here is

so, there are approximately 247 molecules.

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2