When doing the experiment where you compress the air in the syringe, you are collecting 5 data points. Each time you are to decrease the volume by mL

This question is incomplete, the missing diagram is uploaded along this question below.

Each time you are to decrease the volume by 4 mL

Explanation:

From the image, we can see that the volumes of each syringes are displayed;

the first syringe reads 22

the second  syringe reads 18

the third syringe reads 14

the fourth syringe reads 10

and the fifth syringe reads 6

Thus, if we notice the consecutive reading on the syringes, we will notice that each successive step reduces the volume by 4 mL

Therefore, Each time you are to decrease the volume by 4 mL

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.