A $200-d{m}^3$ constant$-$volume batch reactor is pressurized to $20$atm with a mixture of $75\%$A and $25\%$ inertc

The gas$-$phase reaction is carried out isothermally at $227C,AB+C$

a$.$ Assuming that the ideal gas law is valid, how many moles of A are in the reactor initially?

What is the initial concentration of $A?$

b$.$ If the reaction is first order: $-r_A=k{C}_A,$ with $k=0\mathrm{.}1\frac{1}{(min)}$

Calculate the time necessary to consume $99\%$ of A$.$

c$.$ If the reaction is second order: $-r_A=k{C}_A^2,$ with $k=0\mathrm{.}7\frac{d{m}^3}{(mol)-\text{m}\text{i}\text{n}}$

Calculate the time to consume $80\%$ of $A.$

D$.$ Calculate the pressure in the reactor for part $($c$)$ if the temperature is $227$ degrees celsius

$**$I honestly just need part D done