Chemical reactions and equations

• A chemical reaction is the process by which one or more substances are changed into different substances.
• In a balanced equation, there must be an equal number of atoms on both sides of the arrow.
• Chemical reactions can be represented using symbols and formulas to show how atoms combine together.
• The reactants are the starting materials, while the products are what's left over at the end of the reaction.
• The reactants are the starting materials that undergo change during a chemical reaction.
• Products are the new substances formed as a result of a chemical reaction.
• Chemical reactions can occur when two elements combine to form a compound (combination reaction).
• To balance a chemical equation, we need to make sure that the same numbers of atoms of each element appear on either side of the equation.
• we should balance the chemical equations to satisfy the law of conservation of mass.
• There are 5 types of Chemical reactions.
• Decomposition reaction is when a compound is broken down into 1 or more simpler products.
• Displacement reaction is when a more reactive metal displaces a less reactive metal.
• Double Displacement Reaction is when products are formed from exchange of ions.
• Exothermic= heat is released, increasing temperature of the surroundings
• Endothermic = heat is absorbed, decreasing temperature of the surroundings
• Redox reaction is short for reduction-oxidation reaction. It occurs whenever one atom loses electrons and becomes oxidised while another gains electrons and becomes reduced.
• Reducing agent is an electron donor that causes other substances to be reduced.
• Oxidising agent is an electron acceptor that causes other substances to be oxidized.
• CaO= quick lime

  Ca[OH]2= slaked lime

  CaCO3= limestone