Question

A novel process for obtaining magnesium from sea water involves several reactions. Write a balanced chemical equation for each step of the process.
(a) the first step is the decomposition of solid calcium carbonate from seashells to form solid calcium oxide and gaseous carbon dioxide
(b)the second step is the formation of solid calcium hydroxide as the only product from the reaction of the solid calcium oxide with liquid water
(c)solid calcium hydroxide is then added to the seawater, reacting with dissolved magnesium chloride to yield solid magnesium hydroxide and aqueous calcium chloride
(d)Thw solid hydroxide is added to a hydrochloric acid solution producing dissolved magnesium chloride and liquid water
(e) Finally, the magnesium chloride is melted and electrolyzed metal and diatomic chlorine gas.

Answer 1

Answer: a) $CaCO_3(s)\rightarrow CaO(s)+CO_2(g)$

b) $CaO(s)+H_2O(l)\rightarrow Ca(OH)_2(s)$

c) $Ca(OH)_2(aq)+MgCl_2(aq)\rightarrow Mg(OH)_2(s)+CaCl_2(aq)$

d) $Mg(OH)_2(s)+2HCl(aq)\rightarrow MgCl_2(aq)+H_2O(l)$

e) $MgCl_2(l)\rightarrow Mg(l)+Cl_2(g)$

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

he salts which are soluble in water are designated by symbol (aq), those in solid form are represented by (s), those in liquid form are represented by (l) and those in gaseous form are represented by (g) after their chemical formulas.

a) decomposition of solid calcium carbonate from seashells to form solid calcium oxide and gaseous carbon dioxide:

$CaCO_3(s)\rightarrow CaO(s)+CO_2(g)$

b) formation of solid calcium hydroxide as the only product from the reaction of the solid calcium oxide with liquid water

$CaO(s)+H_2O(l)\rightarrow Ca(OH)_2(s)$

c) calcium hydroxide is then added to the seawater, reacting with dissolved magnesium chloride to yield solid magnesium hydroxide and aqueous calcium chloride

$Ca(OH)_2(aq)+MgCl_2(aq)\rightarrow Mg(OH)_2(s)+CaCl_2(aq)$

d) solid hydroxide is added to a hydrochloric acid solution producing dissolved magnesium chloride and liquid water

$Mg(OH)_2(s)+2HCl(aq)\rightarrow MgCl_2(aq)+H_2O(l)$

e) magnesium chloride is melted and electrolyzed metal and diatomic chlorine gas.

$MgCl_2(l)\rightarrow Mg(l)+Cl_2(g)$