An internal combustion engine uses propylene $(C_3{H}_6)$ as a fuel. The molecular weights of air and propylene are $29$ and $42\frac{g}{m}ol,$ respectively. It is required to:

Write the balanced chemical equation for propylene with stoichiometric oxygen. $(2$ marks$)$

Write the balanced chemical equation for propylene with $15\%$ excess air. $(2$ marks$)$

Obtain the stoichiometric air$/$fuel ratio. $(2$ marks$)$

Obtain the actual air$/$fuel ratio. $(2$ marks$)$

Calculate the fuel$-$equivalence ratio. $(2$ marks$)$

Determine if the fuel mixture is rich or lean. $(1$ mark$)$