Problem 96 - Chemistry: An Atoms-Focused Approach

Question

Can a barometer be used to measure just the partial pressure of oxygen in the atmosphere? Why or why not?

Step-by-Step Solution

Answer

Answer: No, a barometer cannot be used to measure the partial pressure of oxygen in the atmosphere as it measures the total atmospheric pressure and cannot distinguish between the pressures exerted by specific gases in a mixture.

Step 1: 1. Understand how a barometer measures atmospheric pressure

: A barometer measures atmospheric pressure by balancing the weight of air above a liquid (usually mercury) in a column or enclosed container. When atmospheric pressure increases, the liquid level rises, and when pressure decreases, the liquid level falls. The height of the liquid column is used to determine the pressure. This is based on the general behavior of gases and their relationship between pressure and volume.

Step 2: 2. Understand partial pressure of gases in a mixture

: Partial pressure is a measure of the pressure exerted by a specific gas in a mixture of gases. The total pressure of the mixture is the sum of the partial pressures of all the individual gases present. According to Dalton's Law of Partial Pressures, in a mixture of non-reacting gases, the total pressure is equal to the sum of the partial pressures of each individual gas. For example, if the atmospheric pressure is 1013 hPa, the partial pressure of oxygen in the atmosphere (approximately 21% of the total pressure) would be around 213 hPa.

Step 3: 3. Determine whether a barometer can measure partial pressure of oxygen

: A barometer is designed to measure the total atmospheric pressure, which is the sum of partial pressures from all gases present in the atmosphere. A regular barometer does not have the capability to selectively measure the partial pressure of oxygen or any specific gas in the atmosphere. It measures the overall pressure exerted by the entire mixture of gases.

Step 4: 4. Conclusion

: A barometer cannot be used to measure just the partial pressure of oxygen in the atmosphere as it is designed to measure the total atmospheric pressure. Barometers are not equipped to distinguish between the pressures exerted by specific gases in a mixture and cannot directly provide information about the partial pressure of oxygen or other individual gases.