2. The reaction can be described in words as follows: aluminum sulfate reacted with ammonium hydroxide forming the insoluble product or precipitate, aluminum hydroxide and the water-soluble ammonium sulfate. The chemical equation can be written as follows (“aq” means aqueous, dissolved in water):
___KAl(SO4)2 (aq) + ___NH4OH(aq) ___Al(OH)3(s) + ___(NH4)2SO4(aq) + ___KOH(aq)
To balance the chemical equation, we need to determine the coefficients of each compound. The number in front of a compound or element is called a coefficient and it indicates the number of molecules or individual units.
In this reaction, we have:
KAl(SO4)2 (aq) + NH4OH(aq) → Al(OH)3(s) + (NH4)2SO4(aq) + KOH(aq)
To balance the equation, we need to ensure that there is the same number of each type of atom on both sides of the equation. Let's start by balancing the aluminum (Al) atoms:
KAl(SO4)2 (aq) + NH4OH(aq) → Al(OH)3(s) + (NH4)2SO4(aq) + KOH(aq)
On the left side, we have 1 Al atom, while on the right side, we have 1 Al atom. That part is already balanced.
Next, let's balance the sulfur (S) atoms:
KAl(SO4)2 (aq) + NH4OH(aq) → Al(OH)3(s) + (NH4)2SO4(aq) + KOH(aq)
On the left side, we have 2 S atoms, but on the right side, we only have 1 S atom. To balance this, we can put a coefficient of 2 in front of NH4OH:
KAl(SO4)2 (aq) + 2 NH4OH(aq) → Al(OH)3(s) + (NH4)2SO4(aq) + KOH(aq)
Now the sulfur atoms are balanced.
Next, let's balance the hydrogen (H) atoms:
KAl(SO4)2 (aq) + 2 NH4OH(aq) → Al(OH)3(s) + (NH4)2SO4(aq) + KOH(aq)
On the left side, we have 8 H atoms, but on the right side, we have 10 H atoms. To balance this, we can put a coefficient of 4 in front of KOH:
KAl(SO4)2 (aq) + 2 NH4OH(aq) → Al(OH)3(s) + (NH4)2SO4(aq) + 4 KOH(aq)
Now the hydrogen atoms are balanced.
Finally, let's balance the potassium (K) atoms:
On the left side, we have 1 K atom, but on the right side, we have 4 K atoms. To balance this, we can put a coefficient of 4 in front of KAl(SO4)2:
4 KAl(SO4)2 (aq) + 2 NH4OH(aq) → Al(OH)3(s) + (NH4)2SO4(aq) + 4 KOH(aq)
Now, both sides of the equation have the same number of atoms for each element, and the equation is balanced.
So the balanced equation is:
4 KAl(SO4)2(aq) + 2 NH4OH(aq) → Al(OH)3(s) + (NH4)2SO4(aq) + 4 KOH(aq)