A student conducts a reaction between hydrochloric acid and calcium hydroxide, as shown in the reaction below: $2$ HCl$($aq$)+$ Ca$($OH$)2($aq$)->$ CaCl$2($s$)+$ H$2$O$($l$)$ In the reaction, the student mixes $10\mathrm{.}0$ mL of $1\mathrm{.}00$ M HCl and $10\mathrm{.}0$ mL of $0\mathrm{.}500$ M Ca$($OH$)2.$ It is determined that $0\mathrm{.}870$ kJ of energy is absorbed in the reaction.

a$.$ Is the reaction endothermic or exothermic? Should the temperature of the reaction increase or decrease?

b$.$ Determine the $$Hrxn by using the moles of HCl$.$ c$.$ Determine the $$Hrxn by using the moles of Ca$($OH$)2.$