The lowest pressure attainable using the best available vacuum techniques is about 10−12 n/m2. part a at such a pressure, how many molecules are there per cm3 at 2 ∘c?

Number of molecules: N = 263.31

Some of the laws regarding gas can apply to ideal gas (volume expansion does not occur when the gas is heated),:

So that the three laws can be combined into a single gas equation, the ideal gas equation

In general, the gas equation can be written

where

P = pressure, atm , N/m²

V = volume, liter

n = number of moles

R = gas constant = 0.082 l.atm / mol K (P= atm, v= liter),or 8,314 J/mol K (P=Pa or N/m2, v= m³)

T = temperature, Kelvin

n = N / No

n = mole

No = Avogadro number (6.02.10²³)

n = m / m

m = mass

M = relative molecular mass

Known

P = 10−12 N / m2

V = 1 cm3 = 10-6 m3

T = 2 ºC = 2 + 273 = 275 K

R = 8,314 J / mol. K

then the number of molecules (N):

N = n x No

N = 4,374.10⁻²² x 6.02.10²³

N = 263.31

Which equation agrees with the ideal gas law

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Which law relates to the ideal gas law

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water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.