Combustion of alkanes

Exercise 2

     

Calculate the mass (n.t.p.) of oxygen required for complete combustion of m = $4,4 \; g $ propane!

$C_3H_8+5O_2\;\rightarrow\; 3CO_2+4H_2O$ $n_{propane}$ $=$ $\frac{m}{M}$ $=$ $\frac{4,4}{44}$ $=$ $0,10\; mol$ $1\;mol$ propane needs $5\;mol\;O_2$ $n_{O_2}$ $=$ $5\cdot 0,10$ $=$ $0,50\; mol$ $m_{O_2}=n_{O_2}\cdot M_{O_2}=22 \;g $