# 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?

Jul 1, 2017

${P}_{\text{Total}} = {P}_{{O}_{2}} + {P}_{H e} + {P}_{C {O}_{2}} \ldots \ldots . .$

#### Explanation:

And so ${P}_{{O}_{2}} = {P}_{\text{Total}} - {P}_{H e} - {P}_{C {O}_{2}}$

$= \left\{101.4 - 82.5 - 0.4\right\} \cdot k P a$

$= 18.5 \cdot k P a$

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 $\text{trimix}$, which is usually $\text{trimix 10/70}$, 10% ${O}_{2}$, 70% $H e$, and 20% ${N}_{2}$.....which is apparently suitable for $100 \cdot m$, i.e. $330 \cdot f t$ depths, which to me are frightening.