Balancing a chemical equation

${\mathrm{FeS}}_2+{\mathrm{O}}_2\to {\mathrm{Fe}}_2{\mathrm{O}}_3+{\mathrm{SO}}_2$

Sum of Co-efficient of reactants and products

Balance a chemical equation by using the hit and trial method?

$2{\mathrm{H}}_2+3{\mathrm{O}}_2\to 2{\mathrm{H}}_2\mathrm{O}$

What is hit and trial method?

String of ants, bees contain

Which of the following is not a balanced equation? 

Balance the following equation:

$\mathrm{Fe}+{\mathrm{H}}_2\mathrm{O}\to {\mathrm{Fe}}_3{\mathrm{O}}_4+{\mathrm{H}}_2$

Balance the following equation:

$\mathrm{Ca}+{\mathrm{H}}_2\mathrm{O}\to \mathrm{Ca}(\mathrm{OH}{)}_2+{\mathrm{H}}_2$

Balance the following equation:

${\mathrm{H}}_2+{\mathrm{N}}_2\to {\mathrm{NH}}_3$

Balance the following equation:

$\mathrm{Fe}+{\mathrm{O}}_2\to {\mathrm{Fe}}_2{\mathrm{O}}_3$

Write the chemical equations in formulae for the given word equations. Also, balance the equations.

Magnesium + Oxygen → Magnesium Oxide.

Write the chemical equations in formulae for the given word equations. Also, balance the equations. 

Calcium + Chlorine →Calcium Chloride.

Write the chemical equations in formulae for the given word equations. Also, balance the equations. 

Silver + Chlorine → Silver Chloride.

Balance the following chemical equations: ${\mathrm{MnO}}_2+\mathrm{HCl}\to {\mathrm{MnCl}}_2+{\mathrm{Cl}}_2\uparrow +2{\mathrm{H}}_2\mathrm{O}$.

Balance the following chemical equations: ${\mathrm{KMnO}}_4+\mathrm{HCl}\to \mathrm{KCl}+{\mathrm{MnCl}}_2+{\mathrm{Cl}}_2\uparrow +{\mathrm{H}}_2\mathrm{O}$.

Balance the following chemical equations: ${\mathrm{KClO}}_3\to \mathrm{KCl}+{\mathrm{O}}_2\uparrow$.

Balance the following chemical equations: $\mathrm{NaOH}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{Na}}_2{\mathrm{SO}}_4+2{\mathrm{H}}_2\mathrm{O}$.

Explain the need of balancing a chemical equation? What information is conveyed by a balanced chemical equation?

Write a complete balance equation for the following: Magnesium ribbon reacts with oxygen to give magnesium oxide.
 

Write a complete balance equation for the following: Zinc reacts with hydrochloric acid to give zinc chloride and hydrogen.