Please look at the following ionic equation
Ca 2+ + 2OH- -> Ca(OH)2
(aq) (aq) (s)
ain't sure whether the state symbols are correct. is Ca2+ soluble or not? thanks everyone.
Originally posted by anpanman:Please look at the following ionic equation
Ca 2+ + 2OH- -> Ca(OH)2
(aq) (aq) (s)
ain't sure whether the state symbols are correct. is Ca2+ soluble or not? thanks everyone.
it has to be in this case... but what's e original equation if there's any
calcium hydroxide is sparingly soluble.
Secondly, whats the original equation?
Ca2+ ion may exist in the aqueous (aq) state.
This is the case when the anion is nitrate ion, for instance.
This is not the case when the anion is sulfate ion, for instance.
At 'A' levels, you have to compare the endothermic lattice dissociation enthalpy and associated (increase in) entropy change, versus the exothermic solvation (hydration) enthalpy and associated (decrease in) entropy change.
If the solution enthalpy and entropy change is feasible, (as in the case of calcium nitrate solution), then you will get Ca2+(aq) and NO3-(aq).
If the solution enthalpy and entropy change is not feasible, (as in the case of calcium sulfate solution), then you will get CaSO4(s).
At 'O' levels, you simply memorize which salts are water soluble and which are not, then write your ionic equation accordingly.
>>> calcium hydroxide is sparingly soluble. <<<
Correct.
The portion which is aqueous is called limewater.
The portion which is solid is called slaked lime.
CaO(s) = Lime
Ca(OH)2(s) = Slaked lime.
Ca(OH)2(aq) = Limewater.
CaCO3(s) = Limestone (small pieces called marble chips).
NaOH(aq) + Ca(OH)2(aq) = Soda Lime.
KOH(aq) + Ca(OH)2(aq) = Potash Lime.
Qn) When you bubble carbon dioxide into limewater, a white ppt is observed. Write equations to explain this.
CO2(g) + H2O(l) --> H2CO3(aq)
H2CO3(aq) + Ca(OH)2(aq) --> 2H2O(l) + CaCO3(s) (white ppt)