do you think that the diameter or the size or the pipes used to transfer O2 from a tank to a patients respirator affect the amount of oxygen that gets in the patient?

answer:

most manufacturers recommend oxygen tubing lengths no more than 50 feet. Longer oxygen tubing will diminish oxygen concentration and effectiveness of therapy. If your oxygen tubing is too short, consider using an oxygen tubing connector to create one long tube from two short tubes

answer:

Strontium oxide

Explanation:

Strontium oxide or strontia, SrO, is formed when strontium reacts with oxygen. Burning strontium in air results in a mixture of strontium oxide and strontium nitride. It also forms from the decomposition of strontium carbonate SrCO₃. 

Silicon-Si

Lanthanum-La

Posporus-P