Answer:
The number of O₂ molecules that are left in the cylinder is 1.70x10²⁴.
Step-by-step explanation:
The number of oxygen molecules can be found using the Ideal Gas law:
Where:
P: is the pressure = 100 psi
V: is the volume = 10 L
n: is the number of moles =?
T: is the temperature = 20 °C = 293 K
R: is the gas constant = 0.082 L*atm/(K*mol)
Hence, the number of moles is:
Now, the number of molecules can be found with Avogadro's number:

Therefore, the number of O₂ molecules that are left in the cylinder is 1.70x10²⁴.
I hope it helps you!