An ideal gas in a 1.25-gallon container is at a temperature of 125 degrees celsius and pressure of 2.5 atmospheres. if the gas is oxygen(formula: o2 molecular weight = 32 grams per mole), what is the mass of gas in the container in units of grams?

You will need the equation PV = nRT

P = Pressure in kPa
V = Volume in L
n = moles
R = 8.314 (constant)
T = Temperature in Kelvin 

First convert 2.5 atm into kPa:

2.5 X 101.3 = 253.25 kPa

Convert 125 Celsius into Kelvin:

125 + 273 = 398 K

Convert Gallons to Litres:

1.25  X 3.79 = 4.74 L

Plug your values into the equation to solve for n:

(253.25)(4.74) = n(8.314)(398)

n = (253.25)(4.74)/(8.314)(398)

n = 0.362 moles

Now use M = m/n to solve for the mass of O2

M = Molar Mass 
M = mass
n= moles

32 = m/(0.362)

m = (32)(0.362) 

m = 11.58g

Sulphur forms two main oxides; the gas sulphur dioxide (SO2) and the liquid sulphur trioxide (SO3). Sulphur dioxide is a dense colourless gas, which is soluble in water, and has a suffocating and unpleasant smell of burnt matches. It has a melting point of -72.7°C, and a boiling point of -10°C.

Sulphur dioxide gas can be made directly by heating its constituent elements. Burning molten sulphur in either air or pure oxygen leads to a reaction, which produces a pale blue coloured flame. This looks quite impressive in a darkened room.

It is produced from the burning of fossil fuels (coal and oil) and the smelting of mineral ores (aluminum, copper, zinc, lead, and iron) that contain sulfur. Sulfur dioxide dissolves easily in water to form sulfuric acid. Sulfuric acid is a major component of acid rain