Measurements show that the enthalpy of a mixture of gaseous reactants increases by 243.kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that −174.kJ of work is done on the mixture during the reaction. Calculate the change of energy of the gas mixture during the reaction in kJ.

The change of energy of the gas mixture during the reaction in 69 kJ

Explanation:

According to first law of thermodynamics:

=Change in internal energy

q = heat absorbed or released

w = work done or by the system

w = work done on the system

w = -174 kJ

q = +243 kJ   {Heat has increased so heat is absorbed}

Thus the change of energy of the gas mixture during the reaction in kJ is 69

im not exactly sure but i think its b!