To determine the pressure of oxygen within the diving tank, we can use Dalton's Law of Partial Pressures, which states that the total pressure of a gas mixture is equal to the sum of the partial pressures of each individual gas.
The formula can be expressed as:
\[ P_{\text{total}} = P_{\text{He}} + P_{\text{O}2} + P{\text{CO}_2} \]
Where:
- \( P_{\text{total}} \) = total pressure of the gas mixture (101.8 kPa)
- \( P_{\text{He}} \) = partial pressure of helium (84.0 kPa)
- \( P_{\text{CO}_2} \) = partial pressure of carbon dioxide (0.900 kPa)
- \( P_{\text{O}_2} \) = partial pressure of oxygen (unknown)
We can rearrange the equation to solve for \( P_{\text{O}_2} \):
\[ P_{\text{O}2} = P{\text{total}} - P_{\text{He}} - P_{\text{CO}2} \] \[ P{\text{O}_2} = 101.8 , \text{kPa} - 84.0 , \text{kPa} - 0.900 , \text{kPa} \]
Now, perform the calculation:
\[ P_{\text{O}2} = 101.8 - 84.0 - 0.900 \] \[ P{\text{O}2} = 101.8 - 84.9 \] \[ P{\text{O}_2} = 16.9 , \text{kPa} \]
Thus, the pressure of oxygen within the diving tank is 16.9 kPa.