Chemical Equations

Chemical Equations

• Chemical equations represent a chemical reaction with symbols and formulae.
• They demonstrate the conversion of reactants (substances before the reaction) to products (substances after the reaction).
• Each formula in an equation represents a molecule or an ion.
• Coefficients (numbers written before a molecule or ion’s formula) indicate the number of each entity involved in the reaction.
• Chemical equations need to be balanced to adhere to the Law of Conservation of Mass, which states that matter cannot be created or destroyed.

Balancing of Chemical Equations

• To balance a chemical equation, the same number of each type of atom has to appear on both sides.
• Write down the number of atoms on both sides separately for each element to check balance.
• You can balance an equation by changing the coefficients, but never change the subscript in a chemical formula.
• Remember, polyatomic ions that appear as reactants and products can be treated as single units when balancing.

Types of Chemical Equations

• There are several types of chemical equations:
  • Synthesis (combination) reactions: Two or more simple substances combine to form a more complex substance.
  • Decomposition reactions: A complex substance breaks down into two or more simpler substances.
  • Single displacement reactions: An element replaces another element in a compound.
  • Double displacement reactions: Elements from two different compounds swap places with each other to form two new compounds.
  • Combustion reactions: A substance reacts with oxygen to produce energy in the form of heat and light.
  • Acid-Base reactions (neutralisation reactions): An acid reacts with a base to produce a salt and water.

Importance of Chemical Equations

• Chemical equations provide crucial information about the reaction, such as which substances react, the products of the reaction, supporting the conservation of mass, and the proportion of substances involved.
• They help to identify and understand the stoichiometry of the reaction, which is the quantitative relationship between reactants and products.
• Chemical equations provide an easy way to calculate the reactants needed or products produced in a chemical reaction.