Science 10- Writing and Balancing Chemical Equations A3.2

Balancing equations

Law of conservation of mass:

  • The mass of the reactants added together will equal thr mass of the products.

H2O = H2 + O2 bceuase hydrogen and oxygen always form as doubles.

To balance this equation, the number of each species of atoms must be the same on each side of the equatiion. Therefore, the balanced equation would be 2H2O → 2H2 +O2

  • Note: A coeffecient is a multiplier for every subscript in the chemicla formula it defines, and is DIFFERENT from a subscript.

A balanced reaction has an equal number of atoms on the product and reactants side. The law of conservation states: What yuou put in, you get out.

  1. Write the chemical formula for each reactant and product, including the state of matter for each one.

  2. Try balancing atom of ion present in the greatest number. Find the lowest common multiple to obtain coefficient to balance the atom/ion

  3. Place coefficients in front of each reactant and product to make the number of atoms equal on each side.

Ex: Na(s) + Cl2 → 2NaCl = 2Na(s) + Cl2(g) (Ionic compound)

Ex: 4K(s) + O2 → 2K2O (Ionic compounds)

Ex: 2H2 + O2 → 2H2O