A reaction at 2.43 atm produces 20.0 L of a gas and evolves 75.3 kJ of heat (exothermic). Calculate the change in internal energy of the system (in kJ).
dE = q + w
You have heat given in the problem. w is -pdV
Substitute and solve for dE
75.3
To calculate the change in internal energy of the system, we can use the First Law of Thermodynamics. The First Law of Thermodynamics states that the change in internal energy (ΔU) of a system is equal to the heat transferred (q) to or from the system, plus any work (w) done on or by the system. Mathematically, it is expressed as:
ΔU = q + w
In this case, the reaction is exothermic, meaning that heat is being evolved by the system. Therefore, q (heat transferred) will have a negative sign (-75.3 kJ).
Since there is no information given about the work done on or by the system, we can assume that there is no work being done (w = 0).
Plugging in the given values, we have:
ΔU = -75.3 kJ + 0
Simplifying this equation, we find that the change in internal energy of the system is:
ΔU = -75.3 kJ
Therefore, the change in internal energy of the system is -75.3 kJ.