Is a candle smelling like a pine tree is that a chemical change chemical property physical change or physical property?

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.

it's c (engineer's do their work with mechanical stuff not on any living being)