# Mass-volume-pressure relationship

## Homework Statement

What is the volume of a sample of oxygen gas has a mass of 50 grams and is under pressure of 1.20 atm at 27 degrees celsius?

## The Attempt at a Solution

Density = Pressure(in pascals)/(specific gas constant * Temperature (in kelvins))

1 atm = 101,325 pascals ~ 1.2 atm = 121,590 pascals
27oCelsius = 300.15 K

Density = (121,590 pascals)/(8.314 * 300.15 K) = 48.72 kg/m3 = 48,720 g/m3

48,720 g/m3 = 50 g/V ~ V = 1.03 x 10-3 m3

## Answers and Replies

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Hint: Ideal Gas Law (PV = nRT)

So... (1.2 atm)(V) = (3.13 mol)(8.314)(300.15 K) ~ V = 6509 L??

Not quite --
1) Oxygen is a diatomic gas (O2)
2) Check your units -- your gas constant (and consequently the volume) is off by (about) two orders of magnitude!
_For your units, the gas constant is approximately 0.0821 L*atm/(K*mol)

(1.2 atm)(V) = (1.56 mol)(0.0821)(300.15 K) ~ V = 32.09 L?

(1.2 atm)(V) = (1.56 mol)(0.0821)(300.15 K) ~ V = 32.09 L?
yes, that is correct

Hi, can someone please help me...its quite urgent....I have two vessels, one has capacity of 0.5l and the other 0.15l. The 0.15l is in a vacuum state held constantly at -80C and the 0.5l vessel is at 50mbar at room temperature (20C). I have gas in the 0.5l vessel......I then open the valve and release the gas to the vacuum upon which it immediately desublimes.. until it reaches equilibrium state and then i close the valve and take the smaller vessel away. What conditions hold at equilibrium??? and how do I find the mass of desublimed solid???