How do u balance these equations with only reactants: CaCO3=, Al+O2=, Fe+CuSO4=, NaOH=, KClO3=, Li+S=, ?

Question

How do u balance these equations with only reactants: CaCO3=, Al+O2=, Fe+CuSO4=, NaOH=, KClO3=, Li+S=, ?

Answer 1

When only one reactant is present, it is a decomposition reaction.  You will need to fill in the products for all of the reactions.

1. Metal carbonates decompose on strong heating to form the metal oxide and carbon dioxide:

CaCO3 ----> CaO + CO2

2. Aluminum will react with oxygen to form aluminum oxide.  While a redox reaction, this is a very simple reaction, so we don't need to balance it with half reactions:

4Al + 3O2 ----> 2Al2O3

3. Iron is a more active metal than copper, so iron metal will displace copper ions from solution.  Iron(II) ions and copper metal will be formed:

Fe + CuSO4 ----> FeSO4 + Cu

4. Hydroxides don't decompose that readily, but I think strong heating will drive off water to form the metal oxide:

2NaOH ---> Na2O + H2O

5. Chlorine is a pretty electronegative element, and so its compounds with oxygen are not that stable.  Metal chlorates will decompose readily on heating to form the metal chloride and oxygen gas:

2KClO3 ----> 2KCl + 3O2

6. This is very similar to the reaction of aluminum with oxygen.  An ionic compound of the two elements will be formed.  Lithium forms Li+ ions, while sulfur will be reduced to sulfide (S2-).  See if you can figure this one out.