Question

An open flask sitting in a lab fridge looks empty, but it is actually filled with a mixture of gases called air. If the flask volume is 2.50 L, and the air is at standard temperature and pressure, how many gaseous molecules does the flask contain?

Answer 1

Answer:
`0.67* 10^(23)` molecules are contained in the flask.

Step-by-step explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number
`6.023* 10^(23)` of particles.

Standard condition of temperature (STP) is 273 K and atmospheric pressure is 1 atm respectively.

According to the ideal gas equation:'

`PV=nRT`

P= Pressure of the gas = 1 atm

V= Volume of the gas = 2.50 L

T= Temperature of the gas = 273 K

R= Value of gas constant = 0.0821 Latm/K mol

`n=(PV)/(RT)=(1* 2.50L)/(0.0821 * 273)=0.11moles`

1 mole of gas contains=
`6.022* 10^(23)` molecules

0.11 moles of gas contains=
`(6.022* 10^(23))/(1)* 0.11=0.67* 10^(23)` molecules

`0.67* 10^(23)` molecules are contained in the flask.