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 4.00 L, and the air is at standard temperature and pressure, how many gaseous molecules does the flask contain

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kobenhavn kobenhavn · Answer 1 · 2020-07-16T03:17:21+02:00

Answer: [tex]1.07\times 10^{23}[/tex] molecules

Explanation:

According to the ideal gas equation:

PV=nRT

P = Pressure of the gas = 1 atm ( at STP)

V= Volume of the gas = 4.00 L

T= Temperature of the gas in kelvin = 273 K ( at STP)

R= Gas constant = 0.0821Latm/kmol

n= moles of gas= ?

Putting in the values we get:

[tex]1atm\times 4.00L=n\times 0.0821Latm/Kmol\times 273K[/tex]

[tex]n=0.178mol[/tex]

Now 1 mole of any substance contains [tex]6.023\times 10^{23}[/tex] molecules at STP

Thus 0.178 mole of any substance contains = [tex]\frac{6.023\times 10^{23}}{1}\times 0.178=1.07\times 10^{23}[/tex] molecules at STP

Thus there are [tex]1.07\times 10^{23}[/tex] gaseous molecules in the flask.