A gas is confined to a cylinder under constant atmospheric pressure, as illustrated in the following figure. When the gas undergoes a particular chemical reaction, it absorbs 825kJ of heat from its surroundings and has 0.62J of work done on it by its surroundings.Whats the Delta H
511.5
To determine the enthalpy change (ΔH) for the given reaction, we need to apply the first law of thermodynamics, which states that the change in internal energy (ΔU) of a system is equal to the heat transferred into the system (q) minus the work done by the system (w).
Mathematically, it can be expressed as:
ΔU = q - w
In this case, the gas absorbs 825 kJ of heat (q = 825 kJ) from its surroundings, and 0.62 J of work (w = 0.62 J) is done on the gas by its surroundings. Since the units are different, we need to convert them to the same unit.
825 kJ = 825,000 J
Now, we can substitute these values into the equation:
ΔU = 825,000 J - 0.62 J
Simplifying:
ΔU = 824,999.38 J
The change in internal energy (ΔU) is equal to the enthalpy change (ΔH) at constant pressure. Therefore, the ΔH for this reaction is approximately 824,999.38 J.