If the partial pressure of Gas A is 45 mmHg, what is its concentration?

To determine the concentration of a gas when given its partial pressure, you can use the formula that relates partial pressure to concentration in a percentage form. The general formula to convert the partial pressure of a gas to its concentration percentage is:

[ \text{Concentration (%)} = \left( \frac{\text{Partial Pressure of the Gas}}{\text{Total Pressure}} \right) \times 100 ]

Assuming we're working under standard atmospheric conditions, the total pressure typically is around 760 mmHg.

Using the given partial pressure of Gas A, which is 45 mmHg, you can calculate its concentration as follows:

[ \text{Concentration} = \left( \frac{45 \text{ mmHg}}{760 \text{ mmHg}} \right) \times 100 ]

[ \text{Concentration} \approx 5.9% ]

This calculation aligns with option D, confirming that the concentration of Gas A is approximately 5.9%. This value accurately reflects the proportion of Gas A in relation to the total atmospheric pressure, which is essential for understanding gas behaviors in various environments and applications in fields such as medicine and environmental science.