Question

What mass of O2, in grams, is required to completely react with 0.025 g C3H8?

Answer 1

2C3H8+ 702--->6CO2+8H20
FROM  Equation  above  2  moles of C3H8    reacted with  7  moles  of oxygen  to  form   6  moles of  c02 plus  8  molesof  H2O  
the  moles  of  c3H8  reacted is = MASS/ R.F.M
THE  R.F.M =48+8=44
Number  of  moles is  hence 0.025/44=5.68x10^-4
 since  ratio  of  C3H8  to   O2 is  2:7  Therefore moles of   O2  reacted  is  1.989 x10^-3
mass= r.f.m  x  number  of  moles
(1.989x10^-3)   x  32 =0.064g