Chemical Equations

Chemical Equations

Chemical reactions can be represented simply on paper by chemical equations involving only formulas and symbols. The reactants are written in their formula form on the left-hand side of the equation, while the products are also written in their formula form on the right-hand side of the equation with an arrow (→) pointing from the reactant to the product.

e.g: Mg + 2HCl → MgCl₂ + H₂

Where a chemical reaction is impossible, it is wrong to write an equation to represent it, e.g., copper does not react with hydrochloric acid so it is incorrect to write the equation.

Balancing Equations

For an equation to be meaningful, it must be balanced. A balanced equation must contain the same number and kind of atoms on both sides of the equation.

Information Provided by the Equation

• It tells us the reactants and products involved in the reaction
• It tells us the physical state of the reactants and products
• Indicates whether a particular reaction is reversible or not

Information Not Provided by the Equation

• The speed of the reaction
• The heat changes during the reaction; this, however, may be indicated where required
• The colors of the reactants and products