Question

Limestone stalactites and stalagmites are formed in caves by the following reaction:


`Ca_2 (aq) + 2HCO^-_3(aq) \rightarrow CaCO_3(s) + CO_2(g) + H_2O(l)`
If 1 mol of CaCO₃ forms at 298 K under 1 atm pressure, the reaction performs 2.48 kJ of P−V work, pushing back the atmosphere as the gaseous CO₂ forms. At the same time, 38.90 kJ of heat is absorbed from the environment.
Find the value of ΔH and ΔE.

Answer 1

ΔH = +38.90 kJ, ΔE = +36.42 kJ

Step-by-step explanation:

The variation in enthalpy is equal to the flow heat. The heat is absorbed from the environment, so the reaction is endothermic, and

ΔH = +38.90 kJ

For the first law of thermodinamycs:

ΔE = ΔH + W

Where W is the work, which is done by the system, so W = - 2.48 kJ

ΔE = 38.90 - 2.48

ΔE = +36.42 kJ