Hi, really need to know this, thanks!
2007-02-07 06:11:58 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
Hess' Law (Energy Changes in a Reaction ) and Carbonate Decomposition:
Reaction 1: Calcium carbonate decomposes on heating as follows:
CaCO3 ¾> CaO + CO2 ---- DH1
Reaction 2: The reaction for the decomposition of magnesium carbonate is similar
MgCO3 ¾> MgO + CO2 ---- DH2
Reaction 3: Calcium carbonate reacts with hydrochloric acid as follows:
CaCO3 + 2HCl ¾> CaCl2 + CO2 + H2O ---- DH3
Reaction 4: Calcium oxide reacts with hydrochloric acid as follows:
CaO + 2HCl ¾> CaCl2 + H2O ---- DH4
Hess' Law predicts that the enthalpy change for the decomposition of calcium carbonate is equivalent to the enthalpy change that results from the sum of reaction 2 and the inverse of reaction 3.
CaCO3 + 2HCl ¾> CaCl2 + CO2 + H2O ---- DH3
CaCl2 + H2O ¾> CaO + 2HCl ---- DH4
¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾¾-
CaCO3 ¾> CaO + CO2 ---- DH1
Therefore: DH1 = DH3 - DH4
2007-02-07 06:18:11 · answer #1 · answered by HoneyBunny 7 · 0⤊ 0⤋
Do you means for its formation, or thermal decomposition?
2007-02-07 14:15:47 · answer #2 · answered by Gervald F 7 · 0⤊ 0⤋