N2(g) + 3H2(g) → 2 NH3(g) CHEMICAL EQUATION A shorthand expression showing the changes that takes place as a result of a chemical change 1 mole of nitrogen gas combined with 3 moles of hydrogen gas to form 2 moles of ammonia gas N2(g) + 3H2(g) → 2 NH3(g) REACTANTS PRODUCT

POINTS TO REMEMBER WHEN WRITING A CHEMICAL EQUATION What are the facts? Are the formulas written correctly? Is the equation balanced? N2(g) + 3H2(g) → 2 NH3(g)

SYMBOLS USED IN CHEMICAL EQUATIONS + Used to separate the formulas of reactants and products → “yields”; separates reactants from products ⇄ Represents a reversible reaction (s) solid (l) liquid (g) gas (aq) Aqueous; dissolved in water ↑ Used as alternative to (g) for a gaseous product ↓ Used as alternative to (s) for a solid product (precipitate) →or → Indicates that heat is supplied to the reaction Indicates the reaction requires a catalyst (ex Pt) heat ∆ Pt