The change in thermal energy of the gas during compression is found using the first law of thermodynamics. After calculating the work done on the gas during compression at constant pressure, the change in thermal energy (ΔU) is determined to be 80 joules.
Step-by-step explanation:
The change in thermal energy of the gas during this compression process can be found using the first law of thermodynamics which states that the change in the internal energy (ΔU) of a system is equal to the heat added to the system (Q) minus the work done by the system (W). Because the process is at constant pressure, the work done by the gas is W = PΔV, where P is the pressure and ΔV is the change in volume. Given that the volume is decreasing during compression, the work done on the gas is positive. Therefore, the change in internal energy (ΔU) is:
ΔU = Q - W
In this specific case:
P = 450 kPa = 450,000 Pa (since 1 kPa = 1000 Pa)
Initial volume (Vi) = 600 cm3 = 600 × 10-6 m3 (since 1 cm3 = 1 × 10-6 m3)
Final volume (Vf) = 200 cm3 = 200 × 10-6 m3
ΔV = Vf - Vi = -400 × 10-6 m3
Heat energy transferred out (Q) = -100 J (negative because it is transferred out of the gas)
Now calculate the work done:
W = PΔV = 450,000 Pa × (-400 × 10-6 m3) = -180 J
Then plug this into ΔU:
ΔU = Q - W = -100 J - (-180 J) = 80 J
Therefore, the change in thermal energy of the gas during compression is 80 joules.
The probable question can be:
A gas is compressed from 600cm3 to 200cm3 at a constant pressure of 450kPa . At the same time, 100J of heat energy is transferred out of the gas.
Part A
What is the change in thermal energy of the gas during this process?