The tanks used by scuba divers contain a mixture of gases that is approximately 80% nitrogen and 20% oxygen. If the total pressure in the air tank is 760 mmHg, what is the partial pressure of each gas?

Question

950 mmHg N2 and 190 mmHg O2

608 mmHg N2 and 152 mmHg O2

680 mmHg N2 and 80 mmHg O2

150 mmHg N2 and 608 mmHg O2

Answer 1

To find the partial pressures of the gases in the mixture, you can use Dalton's law of partial pressures. The partial pressure of each gas in a mixture is calculated by multiplying the total pressure by the fractional composition of each gas.

Given:

• Total pressure (P_total) = 760 mmHg
• Fraction of nitrogen (N2) = 80% = 0.80
• Fraction of oxygen (O2) = 20% = 0.20

Now, calculate the partial pressures:

1. Partial pressure of nitrogen (P_N2): \[ P_{N2} = P_{total} \times \text{Fraction of N2} = 760 , \text{mmHg} \times 0.80 = 608 , \text{mmHg} \]

2. Partial pressure of oxygen (P_O2): \[ P_{O2} = P_{total} \times \text{Fraction of O2} = 760 , \text{mmHg} \times 0.20 = 152 , \text{mmHg} \]

So, the partial pressures are:

• \(P_{N2} = 608 , \text{mmHg}\)
• \(P_{O2} = 152 , \text{mmHg}\)

Therefore, the correct answer is 608 mmHg N2 and 152 mmHg O2.