Chemical Nomenclature and Chemical reactions

1. Chemical Nomenclature and Chemical reactions

2. Naming Binary Covalent Compounds (Molecular Compounds) • Non-metals form bonds by sharing electrons rather than transferring them. • The resulting bond is referred to as a covalent bond. • *The element farthest to the left or lower on the periodic table is generally written first. Subscripts are replaced by numerical prefixes in the name. CHM 1010 PGCC Barbara Gage

3. Naming Molecular Compounds Greek prefixes are used to denote the number of atoms of each element present.

4. Naming Binary Covalent Compounds CHM 1010 PGCC Barbara Gage

5. Covalent Binary Compounds • CO2 carbon dioxide • N2O dinitrogen oxide • P2S5diphosphoruspentasulfide • SiCl4 silicon tetrachloride • *For compounds where two vowels occur together when the prefix is added, the vowel from the prefix can be dropped (except for iodine). • N2O5 dinitrogenpentaoxide CHM 1010 PGCC Barbara Gage

6. Rules for Naming Covalent Compounds *Mono is not written if there is just a single atom on the first element in the name. Example: CO2 carbon dioxide notmonocarbon dioxide Example: CO carbon monoxide

7. Diatomic Molecules *There are 7 nonmetals and one metalloid that exist in nature as diatomic molecules. They cannot exist in nature as a single atom. Di-Atomic Formula: Br2 At2 I2 N2 Cl2 H2 O2 F2 Given the name of the element – Bromine, nitrogen, chlorine, hydrogen, oxygen, fluorine, Astatine (means 2) atoms How to Remember- 7 make a “7” and hydrogen

8. PROBLEM: SOLUTION: Determining Names and Formulas of Binary Covalent Compounds (a) What is the formula of carbon disulfide? (b) What is the name of PCl5? (a) Carbon is C, sulfide is sulfur S and di-means 2 - CS2. (b) P is phosphorus, Cl is chloride, the prefix for 5 is penta-. Phosphorus pentachloride. CHM 1010 PGCC Barbara Gage

9. Are the following compounds ionic or covalent? f. dinitrogen tetraoxide a. H2O g. FeS b. Sodium chloride h. Cobalt (III) chloride c. CuSO4 i. H2S d. CO j. PF3 e. Lithium hydroxide

10. Writing Formulas From Names CO Write the formulas for the following compounds. 1. carbon monoxide 2. nonacarbon tetrachloride 3. hexabromine dioxide 4. phosphorus trichloride 5. octanitrogenpentafluoride C9Cl4 Br6O2 PCl3 N8F5

11. Naming Binary Compounds (Covalent)independent practice 1. SO2 2. N2O 3. CCl4 4. N2O5 Sulfur dioxide Dinitrogen monoxide Carbon tetrachloride Dinitrogenpentoxide 5. N2O4 6. OF2 Dinitrogen tetroxide Oxygen difluoride

12. Naming binary ionic compounds The name of the cation (positively charged ion) is written first, followed by that of the anion. The name of the cation is the same as the name of the metal. Many metal names end in -ium. The name of the anion (negatively charged ion) takes the root of the nonmetal name and adds the suffix -ide. Calcium and oxygen form calcium oxide. Aluminum and sulfur form aluminum sulfide. CHM 1010 PGCC Barbara Gage

13. Naming Ionic Binary Compounds CHM 1010 PGCC Barbara Gage

14. PROBLEM: Name the ionic compound formed from the following pairs of elements: Naming Binary Ionic Compounds (a) magnesium and nitrogen (b) iodine and cadmium (c) strontium and fluorine (d) sulfur and potassium Use the periodic table to decide which element is the metal and which the nonmetal. The metal (cation) is named first and we use the -ide suffix on the nonmetal name root. PLAN: SOLUTION: (a) magnesium nitride (b) cadmium iodide (c) strontium fluoride CHM 1010 PGCC Barbara Gage (d) potassium sulfide From Silberberg, Principles of Chemistry

15. Naming Ionic Compounds- (write the name or the formula for the following binary ionic compounds) Sodium Bromide Calcium Oxide Lithium Sulfide Magnesium Bromide KI MgO AlCl3 Na3N Ca2C Li2S • NaBr • CaO • Li2S • MgBr2 • potassium iodide • magnesium oxide • aluminum chloride   • sodium nitride   • calcium carbonide  • lithium sulfide

16. CHM 1010 PGCC Barbara Gage

17. Chemical and Physical Changes • Chemical Change – Results in formation of a new substance • Ex. Burning(combustion), rusting (oxidation) • Physical Change – Effects only physical properties like size, shape, state of matter

18. Chemical Reactions • Chemical reactions always result in the formation of new substances • reactants - enter into a chemical reaction • products - produced by a chemical reaction • chemical reactions always involve a change in energy • valence electrons are involved in chemical bonding • ionic - transfer • covalent – shared • Metallic – sea of electrons

19. Energy of Chemical Reactions • Exothermic - energy is released • burning • energy of products is less than of the reactants • Endothermic - Energy is absorbed • energy of products is more than of the reactants • Activation energy - the energy needed for a chemical reaction to occur - energy needed to “climb” to the top of the “energy hill”

20. Rates of Reactions • Kinetics - study of reaction rates • Collision theory states that reaction rate depends on • concentration - amount per unit volume concentration reaction rate • surface area - how much of the material is exposed surface area reaction rate • temperature - temperature reaction rate • catalysts - a substance that increases rate by lowering the activation energy - unchanged by the reaction

21. Chemical Equations • Law of the conservation of mass - mass is neither created or destroyed • # of atoms stays the same on both sides of the arrow • Chemical equations can be balanced • use coefficients only NOT SUBSCRIPTS • Coefficient – number placed in front of symbols and formulas which changes the total number of atoms of an element

22. Steps to Balance Equations • Write a chemical equation with correct symbols and formulas. • Count the number of atoms of each element on each side of the arrow. • Balance atoms by using coefficients. • Check your work by counting atoms of each element on both sides of arrow. The numbers of atoms of a particular element must be equal on both sides.

23. Balancing equation practice • http://education.jlab.org/elementbalancing/index.html