Why is pneumatic bottled compressed gas usually CO2 instead of compressed air?

Question

Bottled compressed gas, like that used to inflate life vests & life rafts, drive pneumatic tools (when not run from a compressor), & etc, is usually CO2.

Answer 1

well you are right on all but the tools part thats just compressed air CO2 is carbon dioxide. it is not compressed air.  

Answer 2

Simple answer:  

a 100% full bottle of CO2 will last 10x longer than a similar size bottle of compressed air.

Reason:

Compressed CO2 turns liquid when compressed, allowing for a much greater volume of gas to be stored.

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