CHEMICAL FORMULAS AND EQUATIONS

1. CHEMICAL FORMULAS AND EQUATIONS Shorthand ways to write the name of a compound/molecule Uses chemical symbols and subscripts Ex. NaCl, H2O, etc… Shorthand ways to write a chemical reaction Uses chemical symbols, subscripts, and coefficients Ex. 2Na+Cl2 2NaCl 2H2+O2  2H2O CHEMICAL FORMULAS CHEMICAL EQUATIONS

2. CHEMICAL EQUATIONS • REACTANTS: • The starting substance(s) in a chemical reaction • Are always to the left of the arrow (yield sign) • PRODUCTS: • The ending substance(s) in a chemical reaction • Are always to the right of the arrow (yield sign) 2H2 + O2 2H2O • COEFFICIENT: • The large number in front of a molecule • Tells you how many molecules you have • SUBSCRIPT: • The small number after an element • Tells you how many atoms you have of that element • YIELD SIGN • Acts like an equal sign

3. CHEMICAL FORMULAS AND EQUATIONS Now what happens when a coefficient is added: • Let’s try a few examples: COUNTING ATOMS You use the subscripts to tell you how many atoms of each element you have