Question

A breathing mixture used by deep sea divers has a total pressure of 101.4 kPa and contains hellum, oxygen and carbon doxide. What is the partial pressure of oxygen if `P_(He) = 82.5 kPa` and `P_(CO_2) = 0.4 kPa`?

Answer 1

`P_"Total"=P_(O_2)+P_(He)+P_(CO_2)........`

Explanation:

And so `P_(O_2)=P_"Total"-P_(He)-P_(CO_2)`

`={101.4-82.5-0.4}*kPa`

`=18.5*kPa`

In commercial diving mixes I am not sure that carbon dioxide would be added in those quantities. I used to do a lot of recreational scuba diving, and of course we filled our tanks with compressed air. Commercial divers, nowadays, use so-called `"trimix"`, which is usually `"trimix 10/70"`, `10%` `O_2`, `70%` `He`, and `20%` `N_2`.....which is apparently suitable for `100*m`, i.e. `330*ft` depths, which to me are frightening.