Question
Calculate the work, w gained or lost by the system when a gas expands from 15 L.to 75 L against a constant external pressure of 1.5 atm. 101.3J=1Lx +9.1kJ -12kJ -9.1kJ +12kJ -8.5kJ
Solution
4.7
(236 Votes)
Isabelle
Professional · Tutor for 6 years
Answer
Here's how to calculate the work done by the system:**1. Understand the concept:*** When a gas expands against an external pressure, it does work *on* the surroundings. This means the system *loses* energy, and the work done *by* the system is negative.* The equation for work done by a gas against a constant external pressure is: w = -PexΔV, where Pex is the external pressure and ΔV is the change in volume.**2. Calculate the change in volume (ΔV):**ΔV = Vfinal - Vinitial = 75 L - 15 L = 60 L**3. Calculate the work (w):**w = -PexΔV = -(1.5 atm)(60 L) = -90 L·atm**4. Convert the work to joules:**w = -90 L·atm × (101.3 J / 1 L·atm) = -9117 J w ≈ -9.1 kJ**Therefore, the correct answer is -9.1 kJ.**