A closed, frictionless piston-cylinder contains a gas mixture with the following composition on a mass basis: 40% carbon dioxide, 25% oxygen, 35% neon The cylinder contains 0.8 kg of the mixture at 260 oC and 450 kPa. Determine the magnitude and direction of work when the mixture undergoes an isobaric process to 95 oC.

W=-37.6kJ, therefore, work is done on the system.

Explanation:

Hello,

In this case, the first step is to compute the moles of each gas present in the given mixture, by using the total mixture weight the mass compositions and their molar masses:

Next, the total moles:

After that, since the process is isobaric, we can compute the work as:

Therefore, we need to compute both the initial and final volumes which are at 260 °C and 95 °C respectively for the same moles and pressure (isobaric closed system)

Thereby, the magnitude and direction of work turn out:

Thus, we conclude that since it is negative, work is done on the system (first law of thermodynamics).

Regards.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.