Question

How many ideal gas molecules would be contained inside a 100 cc flask at room temperature and pressure

Answer 1

Using T=300 at 1atm, converting 100cc to 0.0001m^3, and using the ideal gas law I get
0.00000406219 mol.
That's about 2.446x10^18 molecules.

Answer 2

The answer is 2.68x10^21 molecules

Step-by-step explanation:

The ideal conditions for an ideal gas are the following, in addition to the data provided by the exercise:

T = temperature = 273.15 K

P = pressure = 1 atm

V = volume = 100 cm^3 = 0.1 L

R = ideal gas constant = 0.082 atm*L/mol*K

n = number of moles = ?

the ideal gas formula is as follows:

P*V = n*R*T

Clearing n:

n = P*V/R*T = ((1 atm)*(0.1 L))/((0.082 atm*L/mol*K)*(273.15 K)) = 0.00446 mol

we use Avogadro's number to calculate the number of molecules:

Molecules = 0.00446 mol * 6.022x10^23 molecules/mol = 2.68x10^21 molecules