Question

calculate the mass and volume of oxygen required at STP to convert 2.4kg of graphite into carbon dioxide.

Answer 1

The equation for the above reaction is as follows:

(graphite is an allotrope of carbon--C)

       C         +       O2 ------->  CO2
         (s)                  (g)                (g)

Therefore 1 mole of graphite requires 1 Mole of O2 to give 1 mole of CO2

Calculate the moles of graphite:

molar mass of C = 12
mass = 2400 g 

moles = mass/molar mass
           = 2400/12
           =200 moles

if 1 mole of C requires 1 mole of O2
then 200 moles requires  = 1 x 200 / 1
                                         = 200 moles
  
            Find mass of oxygen: (molar mass of O2= 32, moles=200)
mass = moles x molar mass
         = 200 x 32
         = 6400g
          = 6.4kg of oxygen
Find the volume of oxygen:

Ideal gas law..... states that 1 mole of an ideal gas occupies 22.4 litres.
                       
                     therefore 200 moles of O2 occupies= (22.4 x 200) liters
   
                                                                               =4480 liters
                 volume of oxygen = 4480 liters

Answer 2

Explanation:

1 mole of graphite © = 12 gms

2.4 kg of graphite = 2400 / 12 = 200 moles

Mass of Oxygen required :

12 gms of graphite © requires 32 grams of oxygen

2.4 kg or 2400 grams of graphite requires = 2400 x 32 / 12 = 6400 gm or 6.4 kg of oxygen

Volume of oxygen required :

1 mole of carbon requires 1 mole of oxygen in 22.4 litres at STP 200 mole carbon

200 mole carbon requires = 200 x 22.4 = 4480 litres of {{O}_{2}} at STP