NOTE This presentation was not made for public

NOTE: This presentation was not made for public use. Please do not use this presentations without my permission and the permission of each of the authors of the photographs, quotes, and other materials that they contain. Thank you, Vicki Hughes Labs and Activities that go with this presentation: Glowstick Bracelets Marble, Cup, Spoon Catalyst Oozing Pumpkins

CHEMICAL BONDING AND IONS BONDS…Chemical Bonds… …and Reactions

Antoine Lavoisier: Law of Conservation of Matter “Matter is not gained or lost in chemical reactions. ” H H 0 H Annoying girlfriend Lavoisier 0 H

Chemical Formulas Na Sodium Chloride Cl Chlorine If 2 grams of sodium reacted with 3 grams of chlorine, how many grams of sodium would be found in the products?

The SUBSCRIPT shows how many of the atom before it is in a molecule. How many carbon atoms are there? CH 4 4 hydrogens subscript

Chemical formulas tell you what elements are in a compound… H Hydrogen 2 1 Dihydrogen Oxide Hydrogen Oxide O Oxygen …and the number atoms of each element.

Sometimes element names are mixed into one name. CH 4 = methane OH = hydroxide Sometimes compounds have a special non-elemental name. Sometimes compounds have a chemical name and a familiar name. H 20 = Dihydrogen oxide = water

Common Chemical Formulas Name Formula Where Found carbon dioxide CO 2 air glucose C 6 H 12 O 6 blood sugar sucrose C 12 H 22 O 11 table sugar water H 2 O everywhere oxygen O 2 air household bleach Na. Cl. O Chlorox hydrochloric acid HCl stomach acid ammonia NH 3 cleaning fluid baking soda Na. HCO 3 grocery item vinegar HC 2 H 3 O 2 grocery item

Atoms are unstable if they have valence electrons that are unpaired. Remember, valence electrons are those that are in the outermost shell. To reach stability, atoms will bond with each other so all of the valence electrons are paired. Not paired

Types of Chemical Bonds Remember, a Chemical Bond is the force that occurs when two or more atoms hold together. When one atom gives up an e- to another atom, ions are formed.

The positive and negative charges caused by moving e-’s from one atom to another causes an attraction between the ions. The attraction bonds the atoms together in an IONIC BOND.

Remember Lewis structures? Use Lewis structures to show ionic bonding! + Na Describe what you just saw. Cl

Sometimes atoms share electrons instead of gaining and losing them. This type of bond is called a COVALENT BOND. H O H Covalent sharing is not always equal. In water, the e-’s spend most of their time around the oxygen.

A covalent bond in which the e-’s spend more time with one atom than the others is considered to be POLAR. Water is an example of a polar molecule. This unequal sharing creates a slight negative charge to one side of the molecule. PHET concentrations

The polarity of water makes it a very good solvent (can dissolve many other substances) because it can bond with lots of other atoms. Why does salt dissolve in water so easily?

Multiple Bonds Triple bond N N When e-’s shift so that more than one pair is shared between two atoms, multiple bonds are formed.

Remember, bonds are typically indicated with a line. Sometimes those lines are connected to form shapes.

Chemical Bonding Animated Tutorials http: //www. kentchemistry. com/links/bondingflashes/bond_types. swf Let’s Practice Making Bonds http: //www. learner. org/interactives/periodic/groups_interactive. html

Dot to Dot Puzzles HCl H 2 O CO 2 (double bonds) CBr 4 SO 2 Li 2 S Na Cl Step 2: Put them together. Na Bonus: N 2 O Step 1: Do Lewis structures. Cl

Dot to Dot Puzzles HCl H 2 O CO 2 (double bonds) CBr 4 SO 2 Li 2 S Bonus: N 2 O Let’s Check It!

http: //www. drkstreet. com/r esources/metallic-bondinganimation. swf Metallic bonds involve a group of packed protons with a net of electrons covering them.

Writing Formulas and Naming Compounds The charge on an ion is called its oxidation number. + Na Cl A binary compound is made of two elements. (Bi=2) Na. Cl

Writing Formulas and Naming Compounds Metals always lose electrons. Nonmetals always gain electrons. NONMETALS METALOIDS METALS Gain e-’s become more negative Lose e-’s become more positive

Oxidation numbers are the number of e-’s an element can gain (and become -) or lose (and become +). +1 +2 Oxidation numbers can be added to the periodic table…. METALS NONMETALS METALOIDS +3 +4 -3 -2 -1

Writing Formulas and Naming Compounds Special elements with more than one possible oxidation number. r me e R e b m ? s thi NAME OXIDATION NUMBER Copper (I) Copper (II) 1+ 2+ Iron (II) Iron (III) 2+ 3+ Chromium (II) Chromium (III) Lead (IV) 2+ 3+ 2+ 4+

Writing Formulas and Naming Compounds Ions alone have oxidation numbers… + Na Cl But when they combine, their compounds are neutral. Na. Cl

Writing Formulas and Naming Compounds The oxidation numbers of the combining positive and negative ions must balance with each other. + Na Cl So that when they combine, their compounds cancel each other out. Na. Cl

Writing Formulas and Naming Compounds You can name a binary ionic compound from the formula using these rules: ACT 8, 9 & 10 1. Write the name of the positive ion. 2. Check to see if the positive ion can have more than one oxidation number (see the previous table). If it has more than one, look at your formula and write the charge of the positive ion in roman numerals inside parentheses. Ex: Iron (II) 3. Write the root name of the negative ion. Ex: chlorine = chlor 4. Add the ending –ide to the root. 2+ Fe _ Name this compound. + 2 F Fe(II)F 2 Iron (II) Flor ide

CHEMICAL REACTIONS

Chemical Equations Scientists write out the reactions of combining chemicals as chemical equations using symbols from the periodic table. + + Na + Cl Na. Cl

Chemical Equations Remember… The elements that are reacting with each other are called the reactants and are shown on the left side of the action arrow. + Na + Cl Reactants Na. Cl Products The compounds formed by the reaction are called products and are shown on the right side of the action arrow.

Reduction-Oxidation Chemical Reactions Oxidation refers to a chemical reaction that commonly involves oxygen. t s u R g n i Mak Oxidation is a reaction in which an atom loses electrons. The atom that loses electrons is said to be oxidized. Examples: rusting of iron, burning of paper. Heat is usually given off. Which element is oxidized? Fe 2 O 3

Reduction-Oxidation Chemical Reactions Reduction is the opposite of oxidation. t s u R g n i Mak Reduction involves the gaining of electrons and the element is negative. The element that gains e-’s is reduced. A reduced material takes electrons and heat is absorbed. Which element is reduced? Fe 2 O 3

OIL RIG What this stands for is: Oxidation Is Loss of electrons Reduction Is Gain of electrons Redox is the shortened term used to identify a reductionoxidation reaction.

Balancing Equations: Equations LEARN Step 1: Count the atoms in the reactants and in the products. Mg + O 2 Mg. O 1 2 Magnesium is balanced…but Oxygen is not. 1 1

Balancing Equations: LEARN Step 2: Choose a coefficient to add more of the element that is not balanced. Mg + O 2 2 Mg. O 1 2 2 1 The number you added indicating more than one atom of a particular element in an equation is called a coefficient. Let’s continue…Now oxygen is balanced, but magnesium is not.

Balancing Equations: LEARN Step 3: Keep the first coefficient. Re-evaluate and now choose a coefficient that balances the second element. 2 Mg + O 2 2 Mg. O 21 2 2 2 Congratulations! Now everything is balanced!

Balancing Equations: PRACTICE Ca + __F Ca. F 2 Check Yourself Ca + __F 2 Ca. F 2

Balancing Equations: LEARN Sometimes equations require a little more thought. HINT: Find the lowest common multiple of 3 and 2 to figure out how many of each ion you need.

Balancing Equations: PRACTICE Practice: Write the formula for combining sodium and oxygen. Na + O 2 Na 2 O Check Yourself 4 Na + O 2 2 Na 2 O

Polish your skill…Let’s play Chem. Balancer. http: //funbasedlearning. com/chemistry/chem. Balancer/default. htm MORE PRACTICE ONLINE AT http: //education. jlab. org/elementbalancing/ READY? …Balance the following equation. ! Li + H 2 O ORLi. OH + H W O 2 R M O T IZ UAnswer: Q P PO 2 Li + 2 H 2 O 2 Li. OH + H 2 EOG 6 & 11 PHET Balancing Equations / PHET reactants, products and leftovers

Balancing Equations 1. 2 Mg + O 2 2 Mg. O POP QUI Z 2. Ca + 2 F Ca. F 2 3. P 4 + 6 Br 2 4 PBr 3 4. 4 Na + O 2 2 Na 2 O 5. 2 Li + 2 H 2 O 2 Li. OH + H 2

Matter and Energy in Chemical Reactions od Pr Reactant uc t Reactant Product Reactants ENTER the reaction. Energy is absorbed or released by the reaction. � Products are PRODUCED by the reaction. u d o r P P ct u d ro Pr o c du t Endo – inside Exo – outside

EXOthermic Reaction = RELEASES energy od Pr Reactant uc t Reactant Product Reactants ENTER the reaction. Energy is RELEASED by the reaction. � Products are PRODUCED by the reaction. u d o r P P ct u d ro Pr o c du t EXOTHERMIC

ENDOthermic Reaction = ABSORBS energy od Pr Reactant uc t Reactant Product Reactants ENTER the reaction. Energy is ABSORBED by the reaction. � Products are PRODUCED by the reaction. u d o r P P ct u d ro Pr o c du t ENDOTHERMIC

Exothermic Reaction = Releases Energy ENERGY ACTIVATION ENERGY = energy required to cause a reaction to occur. Energy RELEASED TIME

Endothermic Reaction = Absorbs Energy ACTIVATION ENERGY Energy ENERGY ABSORBED TIME

Catalysts are special molecules that aid in making chemical reactions happen but are not used up themselves Catalysts reduce the activation energy! ACTIVATION ENERGY = energy required ENERGY to cause the reaction to occur. TIME

What Affects Chemical Reactions? Concentration of Reactants = greater concentration/more reaction Temperature = high temperature/more reaction Surface area = more surface area/more reaction Catalyst = lowers activation energy/reaction occurs more easily

Any Questions? ACT 11

Acids, Bases and p. H When you place an acid… … into water… … it releases H+ ions. When you place a base… … into water… … it releases OH- ions. PHET acid-base-solutions_en

1 H+ H+ – More hydrogen ions make the solution acidic. H+ OH OH– H+ H+ H+ Acidic solution Increasingly Acidic [H+] > [OH–] The p. H Scale ranks the amount of hydrogen ions (H+) that are in a solution. p. H Scale 0 Battery acid Gastric juice, 2 lemon juice 3 Vinegar, beer, wine, cola 4 Tomato juice 5 Black coffee Rainwater 6 Urine Less hydrogen ions make the solution basic. OH– OH– H+ H+ OH– + H H+ H+ Neutral [H+] = [OH–] Saliva 7 Pure water Human blood, tears 8 Seawater Neutral solution Acidity and basicity are indicated by p. H or litmus paper. OH– OH– H+ OH– – OH OH– H+ Basic solution Increasingly Basic [H+] < [OH–] 9 10 Milk of magnesia 11 Household ammonia 12 Household 13 bleach Oven cleaner 14

How do you neutralize an ACID spill? ACID SE ACID BA BASE WATER

Indicator = changes color in response to change in p. H ACT 12 litmus paper p. H paper phenolpthaleine p. H Interactive Lab http: //splash. abc. net. au/res/i/L 5814/index. html

STATES OF MATTER PHET States of Matter

Changes in state = melting, freezing, evaporation, condensation, sublimation, deposition. ACT 13 Movement of Solids, Liquids, Gases http: //chimianet. zefat. ac. il/download/3_states_matter. swf

BEHAVIOR OF GASES Kinetic Molecular Theory (of Gases) 1. constant, random motion 2. continuous movement in straight line until collision 3. mostly empty space 4. no attraction forces 5. elastic collisions (bounce) 6. kinetic energy depends on temperature PHET Gases

Quizlet. com TJCA 8 th Unit 2 b Chemical Bonds and Reactions ACT 14 I’m diggin’ for questions! Got any?

Let’s Get Chemical! Use the materials you have been given to design and perform tests showing each of the following physical characteristics of matter. Answer the questions and turn in your worksheet. Physical Property Materials to Use Conductivity wire, battery Magnetism magnets Malleability ball of foil Solubility salt, water, flour Density of Liquids oil, water, clear cup, pipet p. H lemon, dish soap, vinegar, milk, litmus paper Density of an irregular object marble, graduated cylinder, balance, water Density of regular object block, balance, ruler