Science 9 Aim: Gain an understanding of how compounds are named

Agenda 1. Atomic Model Assignment due 2. Test Goodie bag 3. Science Sizzler 4. Naming Compounds notes 5. Tomorrows class 6. Quiz Tomorrow

Naming Compounds What are some chemicals that you have at home? Each of these compounds has a chemical name and a chemical formula The formula identifies the elements and how much of each element is in each compound.

For example: Table salt has a chemical formula of NaCl, and the name of it is sodium chloride. Baking soda has a chemical formula of NaHCO 3 and the name of it is sodium bicarbonate.

Naming Chemical Compounds Until the 18 th century, there was no standard system for naming chemicals. Created a lot of confusion Ex. Hydrochloric acid and muriatic acid In 1787, a French chemist named Guyton de Morveau created a naming system, or nomenclature, for compounds.

He decided to use each chemical name for each element in the compound The metal element would always go first Ex. For zinc and oxygen, the name of the compound would be zinc oxide. Since 1920, the International Union of Pure and Applied Chemistry (IUPAC) has been the body responsible for naming every chemical compound discovered.

Interpreting Chemical names and formulas from compounds If you know only the formula of a compound, you can determine its chemical name. If you know only the name, you can determine the formula. Ex. Table salts chemical name, sodium chloride indicates that the compound is made up of one atom of each, just like its formula NaCl does too.

In water, the formula is H 2 O. The small 2 next to the H (called a subscript) indicates that there are two atoms of hydrogen to go with every atom of oxygen in water. Subscript numbers in chemical formulas indicate the number of atoms of elements that must combine to form compounds. If only one atom of an element is needed, no subscript is needed.

Indicating the Physical State of a Compound The state of an element or compound at room temperature is often also indicated in the formula. Written as a subscript in brackets; solid = (s), liquid = (l), gas = (g), and aqueous = (aq) Aqueous refers to solutions (substances dissolved in water.

CompoundChemical Formula ElementsNo. of atoms of each Total # of atoms State Sodium chloride NaCl (s) waterH 2 O (l) Mercury II chloride HgCl 2(s) Potassium phosphide K 3 P (s) Hydrogen fluoride HF (g) Hydrochloric acid HCl (aq)

Class Work questions on page 143. Answer questions 1-4 We will go over as a class