Balancing a chemical equation:
To balance the given or any chemical equation, follow these steps:
Fe(s) + H2O(l) ----> FE3O4 (s)+ H2 (g)
(1) Write the number of atoms of elements present in reactants and in products.
(2) Balance the atom which is the maximum in number; on either side of chemical equation.
In this equation, the number of oxygen atom is the maximum on Right Hand Side(RHS)
To balance the oxygen one needs to multiply the oxygen on the Left Hand Side (LHS)by 4; so that the number of oxygen atoms becomes equal on both sides.
Fe(s) + 4 x H2O(l) ----> FE3O4 (s)+ H2 (g)
(3) Now, the number of hydrogen atoms becomes 8 on the LHS; which is more than that on the RHS. To balance it, one needs to multiply the hydrogen on the RHS by 4.
Fe(s) + 4 x H2O(l) ----> FE3O4 (s)+ 4 x H2 (g)
(4) After that number of oxygen and hydrogen atoms becomes equal on both sides. The number of iron is one on the LHS, while it is three on the RHS. To balance it, multiply the iron on the LHS by 3.
3 x Fe(s) + 4 x H2O(l) ----> FE3O4 (s)+ 4 x H2 (g)
(5) Now the number of atoms of each element becomes equal on both sides. Thus, this equation becomes a balanced equation.
3Fe(s) + 4H2O(l) ----> FE3O4 (s)+ 4H2 (g)
On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper oxide (black), oxygen gas and a brown gas X is formed
(a) Write a balanced chemical equation of the reaction.
(b) Identify the brown gas X evolved.
(c) Identify the type of reaction.