3 part tricky physics problem-Determine the number of moles of oxygen gas in the following containers.

Question

Determine the number of moles of oxygen gas in the following containers.

Container A holds 0.60 m^3 at 25 degree's celsius and an absolute pressure of 11 kPa.

Express your answer using two significant figures.

Container B holds 0.60 m^ at 57 degree's Faranheit and an absolute pressure of 13 kPa.

Express your answer using two significant figures.

Container C holds 0.20 m^3 at 25 degree's Celcius and gauge pressure of 33 kPa .

Express your answer using two significant figures.

Answer 1

Not really very tricky.  Just use the ideal gas law for all three parts.

PV = nRT

where:

P = pressure (given in the problem)

V = volume (given in the probem)

n = number of moles

R = ideal gas constant (which you can look up in your book or on internet)

T = temperature (given in the problem)

Rearange to solve for "n":

n = PV/(RT)

Be sure to convert "T" to absolute temperature (Kelvin degrees)

Answer 2

Assuming that oxygen gas in the containers obeys equation of state of ideal gas (or perfect gas)  pV = nRT , where R = 8.31 J/mol/°K is the ideal gas constant

n = pV / RT

Container A:

p = 11,000 Pa, V = 0.60 m³, T = 25 + 273 = 298°K

n = (11,000x0.60) / (8.31x298)

n = 2.67 moles

Container B:

Express the temperature in °K and p in pascals

Container C:  

Absolute pressure = gauge pressure + 1 atmosphere (101 kPa)

Answer 3

Elaborating on what rick said::

in 1)

P=11kpa ==11000 pa

V=0.60 m^3

n=?

R= Gas constant (I forgot the value,but think its 0.821? )

T=25 degrees Celsius =273+25 kelvin = 298 kelvin..

now,

PV=NRT

just put in the value and solve it :)