Question

how to balance a chemical equation

Answer 1

make a table first and then write in the first column elements and write all the elements given in the equation and in the second column write lhs an write the no.of atoms on the elements and then in the 3 rd write rhs and all the no. of atoms in the right hand side and then balance it.

Answer 2

Chemical Equation Consists Of Reactants and Products  .
Reactants and Products are seperated by equality Sign .
Reactants are written on LHS  and Products on the RHS .

Steps Of Balancing Chemical Equation :
1.Write the Unbalanced Equation .
  For Example :    SnO2 + H2 → Sn + H2O
2. Balance the Equation :
  Apply law Of Conservation Of Mass ( the mass of the products is equal to the mass of reactants ) to get the same number of atoms of every element on each side of the equation.
Tip: Start by balancing an element that appears in only one reactant and product.
  Example :
       SnO2 + H2 → Sn + H2O
Here consider Element O .
In this case, there are two oxygen atoms on the lefthand side of the equation and only one on the righthand side. Correct this by putting a coefficient of 2 in front of water . Hence equation Becomes
             SnO2 + H2 → Sn + 2H2O

Once One element is balanced check for the Other Element until all the elements are balanced .  
This puts the hydrogen atoms out of balance. Now there are two hydrogen atoms on the left and four hydrogen atoms on the right. To get four hydrogen atoms on the right, add a coefficient of 2 for the hydrogen gas. Remember, coefficients are multipliers, so if we write 2 H2O it denotes 2x2=4 hydrogen atoms and 2x1=2 oxygen atoms.
                       SnO2 + 2 H2 → Sn + 2 H2O
             The equation is now balanced .

3 . Indicate the physical states of the reactants and products.
 
             SnO2(s) + 2 H2(g) → Sn(s) + 2 H2O(g)

Hope You Understood the answer!