CHEMISTRY REVIEW

1. CHEMISTRY REVIEW

2. Ionic Bonding • Ionic compounds are formed when one or more valence electrons are transferred from a metal atom to a non-metal atom.

3. General properties • high Melting Point , Boiling point and hard. It takes a lot of energy to break the bonds between the ions. • When ionic compounds are dissolved in water they dissociate into their ions. • Conduct electricity when dissolved in water • NaCl(s) Na+(aq) + Cl-(aq)

4. Example – Ca bonds with O Step 1 • Ca O Step 2 • 2+ 2- • Ca O Step 3 • 2+ 2- • Ca O Step 4 • Ca2O2 = CaO • The 2’s disappeared because we reduced to lowest terms.

5. IUPAC nomenclature  • is a system of naming chemical compounds. It is maintained by the International Union of Pure and Applied Chemistry.

6. Ionic Binary compounds • A binary compound is one that only contains two elements in the compound. • An ionic binary compound is a compound contains one metal and one non-metal.

7. Ionic Binary Compounds: IUPAC Naming • Consists of two types of monoatomic ions • The metal ion is always written first and retains its whole name • The non-metal is written second and has a slight change, the ending (suffix) is changed to –ide Example: • Na+Cl- use the cross over method NaCl • IUPAC name: sodium chloride • The metal name is written in full and the non-metal has the –ide­ suffix added to it. • Sodium chloride

8. Binary compounds can be made up of more than two ions, provided that there are only two types of elements. Example: Al2O3

9. Ionic Multivalent Binary Compounds • A multivalent compound is one that may have varied numbers of electrons in its valence shell. This means that they can form compounds in various proportions. • SnO2 Sn4+O2- tin (IV) oxide • SnO  Sn2+O2- tin (II) oxide

10. Polyatomic Ions • Polyatomic Ions are ions that are composed of more than one atom. The entire molecule carries a charge to it. Also Called Radicals (Bottom of Data Sheet) Ammonium, Acetate, Carbonate, Nitrate, hydroxide, Phosphate, Sulphate, Chlorate, Bromate, Iodate.

11. Polyatomic Ions • Example-

12. Bonding • Ionic Bonding with polyatomic ions occurs in the same manner as it does with binary atomic molecules. (Use the crossover method) Examples. • . NaOH = • sodium hydroxide • Cu(ClO4)2 = • copper (II) perchlorate • Tin (IV) chlorate = • Sn (ClO3)4

13. Example

14. Word Equations • A word equation is a way of representing a chemical reaction: It tells you what reacts and what is produced. • Examples: • Silver nitrate + copper  silver + copper (II) nitrate  Reactants Products • Hydrogen + Oxygen  water vapour Reactants Products

15. The Conservation of Mass • In a chemical reaction, the total mass of the reactants is always equal to the total mass of the products. • This tells us a few things. • Atoms do not change in a reaction. The molecules that they form can be changed but the atoms themselves are not. • Mass cannot be destroyed. If it could we could use E = MC2 to create energy

16. Skeleton equations + Balancing Equations Example: • CH4 + O2 H2O + CO2 • The above equation does not demonstrate the Law of Conservation of Mass. The law states that the mass of the products will equal the mass of the reactants. This one does (it is balanced) • CH4 + 2 O22 H2O + CO2

17. Balancing • We can’t change the formulas of the products or reactants so the only thing we can do is change the number of molecules instead of their formulas. • CH4 + O2 + O2 H2O +H2O + CO2 • = CH4 + 2O2 2H2O+ CO2 • Now the chemical equation is balanced and the mass of the reactants will equal the mass of the products. You must add Molecules to Balance the atoms!!!

18. 7 Steps to Balance • Check for Diatomic Molecules: (H2, N2, O2, F2, Cl2, Br2, & I2 • Balance Metals • Balance Non-metals • Balance Oxygen • Balance Hydrogen • Recount All Atoms (Reduce if possible.)

19. Types of chemical reactions 0. Combustion Reaction • The reaction of a substance with oxygen, producing oxides and energy • Fuel + oxygen  oxides + energy • AB + oxygen  common oxides of A and B (ex AO, BO)

20. 1. Synthesis Reaction • -A chemical reaction in which two or more substances combine to form a more complex substance. • A + B  AB • Example: • 2CO(g) + O2(g) pt2CO2(g)

21. 2. Decomposition reaction • -A chemical reaction in which a compound is broken down into two or more simpler substances. • AB  A + B • Example: The decomposition of water. • 2H2O(l) + electricity 2 H2(g) + O2(g)

22. 3. Single Displacement reaction • -A reaction of an element with a compound to produce a new element and a new compound. The reaction will only occur if the element is higher on the reactivity series than the metal in the compound. (Reactivity series on the next slide) • A + BC  AC + B • Example: • Cu(s) + 2AgNO3(aq) 2Ag(s) + Cu(NO3)2(aq)

23. 4. Double displacement reaction • - A reaction in which aqueous ionic compounds rearrange cations and anions, resulting in the formation of new compounds. • AB + CD  AD + CB • Example: • Pb(NO3)2 (aq) + 2KI (aq) PbI2 (s) + 2KNO3 (aq)

24. WHEN DOES A REACTION OCCUR? A reaction will only occur if the element is higher on the reactivity series than the metal in the compound.

25. Chemical reactions in solution • A Solution is a homogenous mixture in which a pure substance, called the solute, is dissolved in another pure substance called the solvent. • The solution is often an aqueous solutionwhich is a solution where water is the solvent.

26. Review of Particle Theory • All Matter is made up of extremely tiny particles • Each Pure substance has its own kind of particles, different from the particles of other pure substances • Particles are always moving. Particles at a higher temperature are generally moving faster, on average than particles at a lower temperature. • Particles attract each other

27. Collision Model (theory) • Atoms and molecules are constantly bumping into each other. If they are moving too slowly no reaction will occur. • Molecules that are moving quickly enough may break bonds between atoms and the atoms may combine to form new molecules (new products). • The exact energy required for a particular old bond to be broken and a new one to be formed is called the 'Activation Energy.

28. Collision Model (theory) • Two factors increase the rate of reaction 1) Number of collisions 2) Number of effective/successful collisions

29. 4 Factors that affect rates of reactions 1. Temperature When the reactants are heated, they bounce and contact more vigorously with other reactant molecules. This increases the number of successful collision and the rate of reaction.This is the most important factor.

30. 4 Factors that affect rates of reactions 2. Concentration • Concentration is defined as the number of molecules of reactants per unit volume. The more the concentration of reactant molecules, the higher the probability of collision due to their sheer number. Excess concentration may have no effect if one of the reactants is used up.

31. 4 Factors that affect rates of reactions 3. Surface Area • By increasing surface area, the number of molecules exposed for collisions is increased. This allows more collisions between molecules to occur and increases the rate of reaction.

32. 4 Factors that affect rates of reactions 4. Catalyst • Catalysts, are chemicals or substances that catalyze or promote a chemical reaction to occur and remaining unchanged in the end. They are like parts of an assembling mechanism that help making the final product but then detach themselves from it. They lower the activation energy.

33. Acids and Bases • Acids are traditionally considered any chemical compoundthat, when dissolved inwater, gives a solution with a hydrogen ion [H+] activity greater than in pure water, i.e. a pH less than 7.0.

34. When Acids are dissolved in water they release H+. • Ex HCl(aq) H+(aq) + Cl-(aq)

35. They also: • Taste sour • Are good conductors of electricity (they release H+ ions when they are in water) • React with compounds that contain carbonate • Are generally quite reactive • Inflict a sharp burning pain when handled • Turn blue litmus red

36. Naming Acids • There are two rules for naming acids when the chemical formula of an acid starts with H and has only one other non-metallic element

37. Naming Acids (with polyatomic ions) • Some acids contain a polyatomic ion. When the polyatomic ion in an acid contains an oxygen atom (O) and its name ends in “ate”, the acid can be named by the steps shown below.

38. Table 1 Examples of common acids include Common acids

39. Acids are widely used in industry, they are used in many manufacturing processes including; fertilizers, explosives, refining oil, and electroplating materials. • Acids that that react with metals and glass are described as being Corrosive. These acids can be dangerous to humans and the environment.

40. Base •  A base is most commonly thought of as an aqueous substance that can accept hydrogen ions. • bases can commonly be thought of as any chemical compound that, when dissolved in water, gives a solution with a pH higher than 7.0.

41. When bases are released in water they release OH- ions • Example • NaOH (aq)­ Na+ (aq) + OH- (aq)

42. They also: • Taste bitter • Are good conductors of electricity (They release OH- ions when dissolved in water) • Break down proteins into smaller molecules • May also be called alkaline • Feel slippery when handled • Turn Red litmus blue

43. Identifying and Naming Bases • A base can also be identified from its name or its chemical formula. A substance is a base if its name begins with the name of a metallic ion and ends with the word “hydroxide.” A substance is also a base if: • the chemical formula starts with a metallic ion or with the ammonium ion NH4+ AND • the chemical formula ends with OH (called a hydroxyl group)

44. Naming Bases • The name of a base can be determined from its chemical formula. Notice that all bases (in this class) are followed by the word “hydroxide.”

45. Naming Bases

46. Table 2 Examples of some common bases

47. Acid - Base Indicators: • The most common indicator is found on "litmus" paper. It is red below pH 4.5 and blue above pH 8.2 • . 

48. Acid - Base Indicators: • Other commercial pH papers are able to give colors for every main pH unit. Universal Indicator, which is a solution of a mixture of indicators, is able to also provide a full range of colors for the pH scale.

50. The Strength of Acids and Bases The strength of acids and bases are not all equal. Some acids and bases are safe enough to eat while others can eat through clothing and metal.