Presentation on theme: "Chemical Formulas and Equations"— Presentation transcript:
1Chemical Formulas and Equations Chapter 9 – 2Part 1
2Chemical FormulasA chemical formula is a shorthand way to use chemical symbols and numbers to represent a substance.A subscript is a number written below and to the right.It tells how many atoms are in this molecule.If there is no subscript, then there is just one atom.C6H12O6Glucose
3Some Basic RulesWhen you have two elements, you have two words in the nameThe first word is the first element.The second word is the second element.
4Continued The second word also ends in “IDE”. Like oxygen becomes oxide.
5Writing Formulas for COVALENT COMPOUNDS Covalent compounds are often composed of nonmetals.The names of many covalent compounds use prefixes.Example: Carbon Dioxide & Dinitrogen monoxideCO2N2O
6Here are the first ten prefixes: Mono-1Hexa-6Di-2Hepta-7Tri-3Octa-8Tetra-4Nona-9Penta-5Deca-10Prefixes Used in Chemical Names
7Writing Formulas Covalent Compounds Use the name of compound to write its formulaEx: Carbon DioxideNo prefix on first atom indicates 1 atomThe prefix di indicates 2 oxygen atoms= CO2Prefixes always used on second atom C0 =carbon monoxideWhat is the formula for dinitrogen trioxide?––> N2O3