I'm given a flow rate of a gas mixture of $3\ \mathrm{Nm^3/h}$ in standard cubic meters through a cylinder of length $50\ \mathrm{cm}$ and cross section $70\ \mathrm{cm^2}$, can I compute how long a particle will stay inside of the cylinder (which would equal the time the particle can react inside the cylinder)?
And what if the temperature changes during the reaction?
If the flow rate would be given in volume per time, I had an idea to compute this, but the use of standard cubic meters is baffling to me.