During an experiment, a student adds 1.23 g CaO
to 200.0 mL
of 0.500 M HCl
. The student observes a temperature increase of 5.10 °C
.

Assuming that the solution's final volume is 200.0 mL
, the density is 1.00 g/mL
, and the heat capacity is 4.184 J/g⋅°C
, calculate the heat of the reaction, Δrxn
.

CaO(s)+2H+(aq)⟶Ca2+(aq)+H2O(l)
CaO
(
s
)
+
2
⁢
H
+
⁡
(
aq
)
⟶
Ca
2
+
⁢
(
aq
)
+
H
2
O
(
l
)