What volume would be occupied by 1.78*mol1.78mol dioxygen gas under conditions of "STP"STP?

2 Answers
Apr 25, 2017

Approx. 40*L40L.

Explanation:

The molar volume at "STP"STP varies from syllabus to syllabus. In general, "STP"STP, "standard temperature and pressure"standard temperature and pressure specifies 1.0*atm1.0atm, and 273*K273K. It is further known that 1*mol1mol of an Ideal Gas occupies 22.4*L22.4L at "STP"STP.

And thus the "volume"volume is given by the product "number of moles"xx"molar volume"number of moles×molar volume if we assume (reasonably) that dioxygen gas behaves ideally under the given conditions.

=1.78*cancel(mol)xx22.4*L*cancel(mol^-1)=??L

What mass does this volume represent?

Apr 25, 2017

39.87" L"

Explanation:

At Standard Temperature and Pressure, "STP" (0^(@)"C" and "1 atm"), "1 mole" of any ideal gas occupies 22.4" Liters of Volume".

color(white)(aaaaaaaaaaaaaaaaa)(22.4" L")/(1" mol")

Knowing this, we can think about this for a second without involving any math or calculations.

If we know 1" mole" of a gas occupies 22.4" Liters of volume" at STP, any number of moles more than 1 would occupy more than 22.4" Liters of volume". How much more volume? Well.

color(white)(aaaaaaaaaaaaaaaaa)(1.78 cancel("moles"))/(1 cancel("mole")) = 1.78

This means, there is 1.78"X" more number of moles. So, since we know all else is held constant ("Temperature and Pressure"), "moles" and "Volume" are directly proportional here so "Volume" will increase by the same magnitude ("Avogadro's Law").

1.78 * 22.4" L" = color(blue)(39.87" L"

Answer: 39.87 L