A cylinder of gas does 970j of work on a pison. The gas also transfer 620j of energy to the pison and the outside while it expands. How much does the internal energy of the gas changes during this expansion?
To find the change in internal energy of the gas during the expansion, you need to consider both the work done on the piston and the energy transferred to the piston and the surroundings.
The change in internal energy (ΔU) can be calculated using the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system:
ΔU = Q - W
where ΔU is the change in internal energy, Q is the heat added to the system, and W is the work done by the system.
In this case, the work done by the gas on the piston is given as 970 J (positive because work is done by the gas) and the energy transferred to the piston and the surroundings is given as 620 J (positive because energy is transferred to the system). So we can write:
ΔU = 620 J - 970 J
ΔU = -350 J
Therefore, the internal energy of the gas changes by -350 J (negative because the internal energy decreases) during this expansion.
To find the change in internal energy of the gas during the expansion, we need to apply the First Law of Thermodynamics, which states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system.
Mathematically, this can be represented as:
ΔU = Q - W
Given that the work done on the piston is 970 J and the energy transferred to the piston and the surroundings is 620 J, we can substitute these values into the equation:
ΔU = 620 J - 970 J
Now we can calculate the change in internal energy of the gas:
ΔU = -350 J
Therefore, the internal energy of the gas decreases by 350 J during this expansion.