Synthesis & Decomposition Reactions

• The periodic table organizes elements into chemical families.
• Elements in the same family will behave similarly in a chemical reaction.
• A chemical change results when the elements or compounds present at the start of a reaction are rearranged into NEW elements or compounds.
• Clues that a chemical change has occurred: A new colour appears, heat or light is given off, bubbles of gas are formed, a solid material (precipitate) forms in a liquid, the change is difficult to reverse.
• There are 4 main types of chemical reactions: Synthesis reactions, Decomposition reactions, Single displacement reactions, Double displacement reactions.
• Synthesis reactions, also called “combination reactions”, involve two or more reactants combining to produce a new product.
• Reactants in synthesis reactions are often elements that combine to make a compound.
• The general formula for synthesis reactions is: X + Y → XY.
• Decomposition reactions involve a large molecule being broken down into two or more simpler molecules or elements, serving as the opposite of synthesis reactions.
• The general formula for decomposition reactions is: XY → X + Y.