Theory:

1. Calculate the mass of \(0.3\) \(mole\) of aluminium (atomic mass of \(Al=27\)).
 
Data:
 
Given moles of aluminium \(= 0.3\) \(mole\)
 
Atomic mass of aluminium \(= 27\)
 
Formula:
 
Numberofmoles=MassofAlAtomicmassofAlMassofAl=Numberofmoles×AtomicmassofAl
 
Solution:
 
By substituting the values to the above formula, we get,
 
MassofAl=0.3×27=8.1g
 
Hence, the mass of \(0.3\) \(mole\) of aluminium \(=8.1\) \(g\)
 
2.
Calculate the mass of \(2.24\) \(litre\) of \(SO_2\) gas at STP.
 
Data:
 
Given volume of \(SO_2=2.24\) \(L\)
 
Atomic mass of \(S=32\)
 
Atomic mass of \(O=16\)
 
Solution:
  
MolecularmassofSO2=32+16×2=32+32=64
  
NumberofmolesofSO2=GivenvolumeofSO2atSTPMolarvolumeofSO2atSTP
  
By substituting the values in the above formula, we get,
 
NumberofmolesofSO2=2.2422.4=0.1mole

Numberofmoles=MassMolecularmassMass=Numberofmoles×Molecularmass=0.1×64=6.4g
 
Hence, the mass of \(2.24\) \(litre\) of \(SO_2=6.4\) \(g\)