Gas Law Problem Solving: Volume Adjustment to STP

What is the final volume of a water vapor sample when adjusted to STP?

A) 22.4 L

B) 3.50 L

C) 8.21 L

D) 4.00 L

Final answer:

C) 8.21 L

Answer:

The final volume of the water vapor sample adjusted to Standard Temperature and Pressure (STP), calculated using the ideal gas law, is approximately 8.21 L.

Explanation:

The question revolves around the concept of ideal gas law and Standard Temperature and Pressure (STP). In essence, the ideal gas law allows us to compute the properties of a gas under different conditions of temperature, pressure, and volume. STP represents the standard conditions under which the property of gas is determined: 273.15 K (0 degrees Celsius) and 1 atm (101.325 kPa).

In this scenario, the sample of water vapor occupies 3.50 L at 265 K and 50 kPa. We want to determine the new volume at Standard Temperature and Pressure (STP). We will use the ideal gas law and manipulate it to Volume (V1) / Temperature (T1) = Volume (V2) / Temperature (T2), where V1 is the initial volume, T1 is the initial temperature, V2 is the final volume, and T2 is the final temperature. In this case, the new conditions also reflect a change in pressure, so we can augment it to (P1 * V1) / T1 = (P2 * V2) / T2, where P1 is the initial pressure, and P2 is the final pressure (which is 101.325 kPa at STP).

After substituting the known values into this formula, we find the final volume (V2) - which is the new volume of the sample when it is adjusted to STP - is approximately 8.21 L. Therefore, the correct answer is C) 8.21 L.