Final answer:
The work done on the gas mixture during the process is 18.00 atm.L.
Step-by-step explanation:
The gas expands at a constant pressure, and its volume increases from 9.00 L to 15.00 L. The heat absorbed by the gas during the process is 800 J.
The work done by the gas can be calculated using the formula:
Work = Pressure x Change in Volume
Substituting the given values, we have:
Work = 3.00 atm x (15.00 L - 9.00 L)
Work = 18.00 atm.L
Therefore, the work done on the gas mixture during this process is 18.00 atm.L.