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?

 molecules are contained in the flask.

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number of particles.

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

According to the ideal gas equation:'

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

1 mole of gas contains=  molecules  

0.11 moles of gas contains=  molecules

 molecules are contained in the flask.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).

the answer is d. 74.02