Question

An open flask sitting in a lab refrigerator looks empty, but it is actually filled with a mixture of gases called air. If the flask volume is 3.50 L, and the air is at standard temperature and pressure, how many gaseous molecules does the flask contain?

Answer 1

9.39 × 10²² molecules

Step-by-step explanation:

We can find the moles of gases (n) using the ideal gas equation.

P . V = n . R . T

where,

P is the pressure (standard pressure = 1 atm)

V is the volume

R is the ideal gas constant

T is the absolute temperature (standard temperature = 273.15 K)

`n=(P.V)/(R.T) =(1atm.3.50L)/((0.08206atm.L/mol.K).273.15K) =0.156mol`

There are 6.02 × 10²³ molecules in 1 mol (Avogadro's number). Then,

`0.156mol.(6.02*10^(23)molecules)/(mol) =9.39*10^(22)molecules`