Balancing Chemical Equations

• A Chemical equations tells what happens when particles of matter interact. The reacting particles are called reactants and the new substance formed are called products. Thus, a chemical equations describes a chemical reactions.
• We use coefficients to balance chemical equations.
• Hydrogen and oxygen from pairs with atoms of their own kind. Elements that form these molecules of two atoms of the same elements are called diatomic. The diatomic elements are hydrogen, oxygen, nitrogen, fluorine, bromine, and iodine. The formulas for their diatomic molecules are as follow.

  H2, O2, N2, F2, Cl2, Br2, I2
• We cannot use subscript to balance equations, because then we would have incorrect formulas.
• Direct Combination is where two or more reaction come together to form a single product, it is also known as synthesis reaction.
• Decomposition reaction is a reaction in which a single compound is broken down into two or more smaller compounds or elements. It is the reverse of a direct combination reaction.
• Single replacement Reaction is the uncombined element displaces an element that is part of a compound. The reactants in a single replacement reaction always one element and one compound.
• Double- replacement reaction is where the atoms or ions from two different compounds replace each other. An identifying characteristics of a double- replacement reaction is the presence of two compounds as products. The reactants in double-replacement reactions are generally ionic compounds.