[convict11]

3Na2CO3  + FeCl3  ----------> NaCl + Fe2(CO3)3


Ca(OH)2 + Al2(SO4)3 ---------> Ca(SO4)3 + Al2(OH)2

The second half of both of these equations are correct. I am not really sure how to make them correct and need help on forming chemical equations. Can anyone help?

[AWK]

3Na2CO3  + FeCl3  ----------> NaCl + Fe2(CO3)3


Ca(OH)2 + Al2(SO4)3 ---------> Ca(SO4)3 + Al2(OH)2

The second half of both of these equations are correct. I am not really sure how to make them correct and need help on forming chemical equations. Can anyone help?

These are examples of double exchange reactions. Count charges of cations and anions!
eg:
CaCl₂ + Na₃PO₄ = Ca₃(PO₄)₂ + NaCl
Ca = 2+
Cl = 1-
Na - 1+
PO₄ - 3-
Start counting from the highest charges on the left side
3 x 2+ + 2 x 3- = 0 hence you need 3 CaCl₂ and 2 Na₃PO₄
The rest is straighforward 6 Cl- need 6 Na+
and reaction is:
3CaCl₂ + 2Na₃PO₄ = Ca₃(PO₄)₂ + 6NaCl

[Donaldson Tan]

3Na2CO3  + FeCl3  ----------> NaCl + Fe2(CO3)3

This reaction is not possible, because Fe³⁺ has a high polarising power due to its high charge. Instead, the carbonate ion breaks due to the polarising nature of Fe³⁺ and you get Fe₂O₃ and CO₂

Ca(OH)2 + Al2(SO4)3 ---------> Ca(SO4)3 + Al2(OH)2

The valency of Al is 3, there is no way you can get Al2(OH)2. The valence for Ca is 2, so there is no way you can get Ca(SO4)3. Try balancing this equation instead: Ca(OH)₂ + Al₂(SO₄)₃ ----> CaSO₄ + Al(OH)₃

On the side note, the structure of Al(OH)₃ is quite debatable. This is due to high acidic character of the Al³⁺ ion. One school of thought supports the original Al(OH)₃ structure while others view Al(OH)₃ as the hydrated form of Al₂O₃, ie. 2Al(OH)₃ = Al₂O₃.3H₂O

[AWK]

On the side note, the structure of Al(OH)3 is quite debatable. This is due to high acidic character of the Al3+ ion. One school of thought supports the original Al(OH)3 structure while others view Al(OH)3 as the hydrated form of Al2O3, ie. 2Al(OH)3 = Al2O3.3H2O

This statement is not true.
Al(OH)3 exists in at least four crystal forms as minerals: Bayerite, Norstrandite, Doyleite and Gibbsite.