If a substance is aqueous, this just means that it is completely dissolved in water and ionized. For example, normal table salt, NaCl when mixed with water completely dissociates (meaning the Na breaks apart from the bond with the Cl and dissolves in the water, causing both to become ionized, Na+ and Cl-. They are ionized in the solution. So the equation would be NaCl + H2O yeilds Na+ + Cl- + H2O; or NaCl (s) + water(l) Yeilds Na+(aq) + Cl-(aq) + -OH (aq) + H+(aq)
The (aq) means aqueous
1) Consider the reaction when aqueous solutions of barium sulfide and nickel(II) iodide are combined. The net ionic equation for this reaction is:
This is two liquid solutions with salts dissolved in them and poured together. If you know your solubility rules then you will see that all sulfides are insoluble except when paired with barium and a few other compounds. So the initial equation is:
BaS(aq) + NiI2(aq) ---------> BaI2 (aq) + NiS (s)
Once your equation is written make sure it is balanced, then break up everything into it's ions except for the solid and make sure every atom is balanced.
Ba2+(aq) + S2+(aq) + Ni2+(aq) + 2I-(aq) -------> Ba2+(aq) + 2I- + NiS (s) now you can cancel out any element that is the same. Must have the same phase as well! The Ba+2(aq) will cancel ion either side. Continue this process until you are left with the elements that make the sold and the solid.
net ionic equation would be.... Ni2+(aq) + S2+(aq) ----------> NiS (s)
These are the aqueous ions it takes to make the solid. Now try the other two on your own if you stiill need help let me know!!
2) When aqueous solutions of aluminum sulfate and potassium carbonate are combined, solid aluminum carbonate and a solution of potassium sulfate are formed. The net ionic equation for this reaction is:
3) When solid Zn metal is put into an aqueous solution of CuSO4, solid Cu metal and a solution of ZnSO4 result. Write the net ionic equation for the reaction.