The chemical equation below shows the burning of magnesium (mg) with oxygen (o2) to form magnesium oxide (mgo).

2mg + o2 mc009-1.jpg 2mgo

the molar mass of o2 is 32.0 g/mol. what mass, in grams, of o2 is required to react completely with 4.00 mol of mg?
2.00

64 grams of will be required to react completely with 4 moles of Mg.

Explanation: The chemical equation of burning of magnesium is given by:

By stoichiometry,

2 moles of Magnesium require 1 mole of oxygen to produce 2 moles of MgO.

Amount of required to form MgO can be calculated by:

Molecular mass of

                               = 64 grams

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.