measurements show that the energy of a mixture of gaseous reactants decreases by 304. kj during a certain…

measurements show that the energy of a mixture of gaseous reactants decreases by 304. 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 - 82. kj of work is done on the mixture during the reaction. calculate the change in enthalpy of the gas mixture during the reaction. be sure your answer has the correct number of significant digits. is the reaction exothermic or endothermic? exothermic endothermic

measurements show that the energy of a mixture of gaseous reactants decreases by 304. 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 - 82. kj of work is done on the mixture during the reaction. calculate the change in enthalpy of the gas mixture during the reaction. be sure your answer has the correct number of significant digits. is the reaction exothermic or endothermic? exothermic endothermic

Answer

Explanation:

Step1: Recall the first - law of thermodynamics and enthalpy formula

The first - law of thermodynamics is $\Delta U=q + w$, and at constant pressure $\Delta H = q_p$. Also, $\Delta U$ is the change in internal energy, $q$ is heat, $w$ is work. Given $\Delta U=- 304\ kJ$ and $w=-82\ kJ$. First, find $q$ from $\Delta U = q+w$. $q=\Delta U - w$

Step2: Calculate the heat $q$

Substitute $\Delta U=-304\ kJ$ and $w = - 82\ kJ$ into the formula $q=\Delta U - w$. $q=-304\ kJ-(-82\ kJ)=-304\ kJ + 82\ kJ=-222\ kJ$ Since at constant pressure $\Delta H = q_p$, and here the process is at constant pressure, $\Delta H=-222\ kJ$.

Step3: Determine the type of reaction

If $\Delta H<0$, the reaction is exothermic. Since $\Delta H=-222\ kJ<0$, the reaction is exothermic.

Answer:

-222 kJ exothermic