A chemical change involves a reorganization of the atoms in one or more substances. For example, when the methane in natural gas combine with oxygen in the air and burns, carbon dioxide and water are formed. This process is represented a chemical equation with reactants on the left side of the arrow and products on the right side. It is important to recognize that in a chemical reaction, atoms are neither created nor destroyed. All atoms present in the reactants must be accounted for among the products. This is achieved by balancing the chemical equation.
The Meaning of a Chemical Equation
The chemical equation gives two important types of information: the nature of the reactants and products and the relative numbers of each. The equation also gives the physical states of the reactants and products. Solid(s), Liquid (l), Gas(g) and in aqueous solution (aq).
Stoichiometric Calculations
Steps to follow:
1. Balance the equation for the reaction
2. Convert the known mass of the reactant or product to moles of that substance.
3. Use the balanced equation to set up the appropriate mole ratios.
4. Use the appropriate mole ratios to calculate the number of moles of the desired reactant or product.
5. Convert from moles back to grams if required.