Measurements show that the enthalpy of a mixture of gaseous reactants increases by 215. 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 -155. kJ of work is done on the mixture during the reaction.

Calculate the change in energy of the gas mixture during the reaction. Round your answer to 2 significant digits.

Is the reaction exothermic or endothermic?

a) ΔU = 370 KJ

b) Endothermic

Explanation:

a)

The change in energy of the mixture can be given by first law of thermodynamics as:

ΔQ = ΔU + W

ΔU = ΔQ - W

where,

ΔQ = change in heat energy of system

ΔU = Change in internal energy of gases

W = Work done on gases = - 155 KJ

For an isobaric process (i.e constant pressure) we know that:

ΔQ = change in enthalpy = ΔH

ΔQ = 215 KJ

Therefore, using values in the equation, we get:

ΔU = 215 KJ - (-155 KJ)

ΔU = 370 KJ

b)

Since, the enthalpy of products is greater than the reactants. Therefore, this is an endothermic reaction.

it should be all of them because it asks if you included all of those in your answer

explanation: