Elemental S reacts with O2 to form SO3 according to the reaction
2S+3O2→2SO3
Part A: How many O2 molecules are needed to react with 6.67 g of S?
Express your answer numerically in units of molecules.
Risposta:
Guarda il stechiometria...#S(s) + 3/2O_2(g) rarr SO_3(g)#
Spiegazione:
The stoichiometric coefficients are in terms of moles, and certainly this REPRESENTS a numerical quantity....i.e. where #N_A="Avogadro's number"=6.022xx10^23*mol^-1#.
With respect to sulfur we got a molar quantity of...
#(6.67*g)/(32.0*g*mol^-1)=0.208*mol#
And therefore CLEARLY we need #0.208*molxx3/2=0.313*mol# OF OXYGEN MOLECULES for stoichiometric equivalence.
#0.208*molxx3/2xx6.022xx10^23*mol^-1=1.88xx10^23*"oxygen molecules."#
And we use la Talpa here precisely as would the #"dozen"#, O l' #"gross"#, as we would any other collective number...
And the mass of this quantity of oxygen is...?