A gas is allowed to expand at constant temperature from a volume of 2.00 L to 11.20 L against an external pressure of 1.500 atm. If the gas loses 256 J of heat to the surroundings, what are the values of q, w, and DU? Pay careful attention to units.
a. -256 J, +838 J, +1094 J
b. +256 J, -1398 J, -1142 J
c. -256 J, -1398 J, -1654 J
d. +256 J, +1398 J, +1654 J
e. -256 J, -419 J, -547 J
Assistance needed.
Please type your subject in the School Subject box. Any other words are likely to delay responses from a teacher who knows that subject well.
A gas is allowed to expand at constant temperature from a volume of 2.00 L to 11.20 L against an external pressure of 1.500 atm. If the gas loses 256 J of heat to the surroundings, what are the values of q, w, and DU? Pay careful attention to units.
mina
q=-256 J
w=-1398 J
DU=-1654 J
A gas is allowed to expand at constant temperature from a volume of 2.00 L to 11.20 L against an external pressure of 1.520 bar. If the gas loses 256 J of heat to the surroundings, what are the values of q, w, and ÄU? Pay careful attention to units.
To determine the values of q (heat transferred), w (work done), and ΔU (change in internal energy), we need to use the first law of thermodynamics, which states:
ΔU = q - w
Given that the gas loses 256 J of heat to the surroundings, we have q = -256 J (negative because heat is being lost).
Next, we can determine the work done, w. When a gas expands against a constant external pressure, the work done is given by the formula:
w = -Pext * ΔV
where Pext is the external pressure and ΔV is the change in volume. In this case, Pext = 1.500 atm and ΔV = 11.20 L - 2.00 L = 9.20 L. We need to convert atm and L to SI units (Joules) for consistent units in the calculation.
1 atm = 101.325 J/L
So, Pext = 1.500 atm * 101.325 J/L = 152.0 J/L
Now we can calculate w:
w = -Pext * ΔV = -152.0 J/L * 9.20 L = -1398 J (negative because work is done on the system).
Finally, we can use the first law of thermodynamics to find ΔU:
ΔU = q - w = -256 J - (-1398 J) = +1142 J
Therefore, the values of q, w, and ΔU are:
q = -256 J,
w = -1398 J,
ΔU = +1142 J.
Looking at the options provided, the correct answer is b. +256 J, -1398 J, -1142 J.