Final Exam Review

1. Final Exam Review Fall 2012

2. Measurement and Significant Figures • Rules for Significant Figures • Any number that is NOT zero is significant. • Any zeroes between 2 numbers is significant. • Any zeroes before any numbers is NOT significant. • Any zeroes after a number is significant ONLY if there is a decimal point anywhere in that number! • Examples • 43.59g • 5043mL • 0.000674mol • 250J • 670.J

3. Measurement and Significant Figures • ADDING/SUBTRACTING • You answer has the same # of significant figures as the number that has the LEAST AFTER THE DECIMAL • Example • 456.12mL + 76.789mL = 532.909mL  532.91mL • MULTIPLYING/DIVIDING • You answer has the same # of significant figures as the number that has the LEAST TOTAL # OF SIG. FIGS. • Example • 8567.10J/ (100.g × 4.184J/g°C) = 20.47586042°C 20.5°C

4. Measurement and Significant Figures • Convert metric units • Use King Henry Died by Drinking Chocolate Milk. • K H D base d c m • Figure out how many spaces you need to move the decimal! • Examples • Convert 45.6 kg to g • How many L are in 12,980mL

5. Measurement and Significant Figures • Converting other things – use Dimensional Analysis • Example • How many inches are in 7.3 feet. (12 in = 1 ft.)? 7.3 ft | 12 in = 88in | 1 ft • How many cups are in 45.0 ounces (oz.) [8oz. = 1 cup] 45.0 oz. | 1 cup = 5.63 cups | 8 oz.

6. Measurement and Significant Figures • Converting Temperatures • TF = 1.8(TC) + 32° or TC = 0.56(TF - 32°) • Example- Convert 98.6°F to °C. TC = 0.56(98.6 ° - 32°) = 37.3°C • Converting Pressures • 1 atmosphere = 760mm Hg = 760 torr = 101,325 Pa • Example- Convert 0.85atm to torr 0.85 atm | 760 torr = 646 torr | 1 atm

7. Matter Definite shape & volume No definite shape or volume Definite volume but NOT shape

8. Matter – Chemical vs. Physical Changes Physical Changes Chemical Changes ALWAYS changes into a new substance Examples: Burning Digesting Rusting Oxidizing Reacting Called a chemical reaction! • NEVER change what the substance is made of • Examples: • Boiling • Freezing • Cutting • Grinding

9. Matter: Pure Substances vs. Mixtures Pure Substances Mixtures A blend of 2 or more pure substances Homogeneous – can’t see each part (tea) Heterogeneous – can see each part (rocky road ice cream) Can be broken down by physical changes • Made of ELEMENTS or COMPOUNDS chemically bonded together • Can ONLY be broken down in 2 ways • Chemical reaction if it’s a compound • Nuclear reaction if it’s an element

10. Matter – Elements and the Periodic Table

11. Matter – Atomic Structure • Atoms make up each element • Atoms are made of protons (p+) and neutrons (n0) in the nucleus and electrons (e-) in the electron cloud surrounding the nucleus. • Protons have a + charge • Neutrons have no charge • Electrons have a – charge (smallest mass) • Atomic # = #p+ (#e-) • Mass # = #p+ + #n0 • Can be rounded from the atomic mass (for the most common isotopes!). • Isotope = atoms of an element that have the same #p+ BUT different #n0

12. Matter – Atomic Structure • Practice – How many protons, neutrons, and electrons are in: • 20782Pb 4120Ca

13. Matter • Electrons exist in orbitals in the electron cloud • Called the ground state – they have the least amount of energy possible • When photons of energy are added to an element, it’s called the excited state!

14. Nuclear Chemistry – Inside the Nucleus • The ONLY way to change an atom of 1 element into another element • Nuclear fusion – 2 atoms combine to create a larger atom + lots of energy!!!! • Stars use fusion to create all the natural elements!!!!! • Nuclear fission – an atom splits into smaller particles • Nuclear particles – released in fission or fusion • Alpha particles – nucleus of a helium atom • Beta particles – electrons • Gamma particles - photons

15. Bonding Ionic Bonds Covalent Bonds Occur between 2 nonmetals Electrons are shared between the atoms • Occur between a metal and a nonmetal • Electrons are transferred from the metal to the nonmetal

16. Ionic Bonds – transfer of electrons

17. Covalent Bonds – share electrons (Lewis Structures) • 1. Add all the valence electrons for each atom • 2. Divide by 2 to determine pairs of electrons • 3. Find center atom and draw end atoms around it • 4. Draw a line (bonding pair of electrons) between each end atom and the center atom • 5. Determine the lone pairs of electrons left over. • 6. Place them around the end atoms 1st, then around the center to make sure that all atoms have 4 pairs around it. • 7. If you run out of lone pairs, create double or triple bonds.

18. Fluorine: • Has the smallest atomic/ionic radius • Has the largest ionization energy • Has the largest electronegativity Periodic Trends • Francium: • Has the largest atomic/ionic radius • Has the smallest ionization energy • Has the smallest electronegativity

19. Nomenclature: Names & Formulas • Writing Formulas • Type I Ionic Compounds (regular metals) • Write the symbol & charge for the cation (metal) • Write the symbol & charge for the anion (nonmetal/polyatomic ion) • Criss-cross the charges. • Example • Calcium phosphate Ca2+ PO43- Ca3(PO4)2

20. Nomenclature: Names & Formulas • Writing Formulas • Type II Ionic Compounds (have transition metals) • Write the symbol & charge for the cation (metal) The charge is given by the Roman numerals! • Write the symbol & charge for the anion (nonmetal/polyatomic ion) • Criss-cross the charges. • Example • Manganese (III) nitrite Mn3+ NO21- Mn(NO2)3

21. Nomenclature: Names & Formulas • Writing Formulas • Type III Covalent Compounds (2 nonmetals • Write symbol of 1st element and prefix becomes a subscript • Do the same for the 2nd element. • Example • Disulfurhexachloride S2Cl6 Prefixes 1- mono 2- di 3- tri 4- tetra 5- penta 6- hexa 7- hepta 8- octa 9- nona 10- deca

22. Nomenclature: Names & Formulas • Writing Formulas • Acids • Binary Acids – Use the prefix hydro in the name!!!! • Write H1+. • Write anion and charge • Criss-cross charges • Example • Hydrosulfuric acid H1+ S2- H2S • Oxyacids – don’t use any prefix • Write H1+ • If name ends in –ic acid, use polyatomic ion ending in –ate. • If name ends in –ous acid, use polyatomic ion ending in –ite. • Criss-cross charges. • Example • Sulfuric acid H1+ SO42- H2SO4 • Nitrous acid H1+ NO21- HNO2

23. Nomenclature: Names & Formulas • Writing Names • Type I Ionic Compounds • Write name of cation (metal). • Write name of anion (nonmetal/polyatomic ion). If it is just a nonmetal, change ending of element to –ide. • Example • Na2O sodium oxide • KMnO4 potassium permanganate

24. Nomenclature: Names & Formulas • Writing names • Type II Ionic Compounds (Transition metals) • Have to write the charge of the metal cation as a Roman Numeral • Write name of cation (metal). • Write the original charge of the metal as a Roman numeral. • Write the name of the anion (nonmetal/polyatomic ion). Change ending of nonmetal to ide. • Example • FeF3 iron (III) fluoride • Cu2CO3copper (I) carbonate

25. Nomenclature: Names & Formulas • Writing names • Type III covalent compounds • Write the name of the 1st element, change subscript to prefix. (Remember, don’t use mono for the 1st element.) • Write the name of the 2nd element, change the subscript to prefix. Change ending to –ide. • Example • SO3 sulfur trioxide • P4O10 tetraphosphorousdecoxide

26. Nomenclature: Names & Formulas • Writing names • Acids • Binary Acid (only 2 elements) • Write hydro + 2nd element’s name + ic acid • Example HCl hydrochloric acid • Oxyacids (polyatomic ion with oxygen in it) • If polyatomic ion’s name ends in –ate, change to –ic acid. • Example H2CO3 carbonate  carbonic acid • If polyatomioc ion’s name ends in –ite, change to –ous acid. • Example H2SO3 sulfite  sulfurous acid

27. The Mole

28. Balancing Equations • When you balance, you write COEFFICIENTS (numbers that go in front of a formula) to make sure that each side of the reaction has the same number of atoms of each element. • Example • NaCl + F2 NaF + Cl2 • H3PO4 + Mg(OH)2  H2O + Mg3PO4

29. Types of Reactions – 5 Types • Synthesis: 2 reactants  1 product • Decomposition: 1 reactant  2 or more products • Single-replacement: 1 element + 1 compound  1 element + 1 compound • Double-replacement: 2 compounds switch ions • Combustion: 1 hydrocarbon + oxygen  CO2 + H2O

30. Stoichiometry • Given an amount of 1 substance, how much of another substance is needed or can you make? • Uses your understanding of moles and balanced equations to solve problems. • Mole Ratio – used to convert between 1 substance and another substance. • You may have to convert your original substance to moles 1st. • You many have to convert your new substance back into mass from moles after you use the mole ratio.

31. Stoichiometry

32. KMT – 5 assumptions 1. Gases are made of tiny particles far apart relative to their size 2. Gas particles are in continuous, rapid, random motion 3. There are no attractive forces between molecules under normal conditions of temperature and pressure 4. Collisions between gas particles and between particles and container walls are elastic collisions. 5. All gases at the same temperature have the same average kinetic energy. The energy is proportional to the absolute temperature.

33. KMT & n, T, V, & P • Why is the air heated in a hot air balloon to inflate it?

34. Attractions that come into play when gases become liquids • van der Waals forces – weak temporary attracts between 2 molecules • Hydrogen bonds – a van der Waals force that deals with the hydrogen on 1 molecule and a nonmetal on another molecule

35. Heat! • q = mCΔT • Endothermic (+q) – heat is added, gets hotter • Exothermic (-q) – heat is removed, gets colder

36. ΔE = q + w • ΔE = change in energy • q = heat • w = work q is + (endothermic) q is – (exothermic) w is + when work is done on the system w is negative when work is done by the system

37. Molarity (M)= a measure of concentration • M = n V • n = moles of solute • V = volume of solution in L

38. Acid-Base Theories Arrhenius Brönsted-Lowry Acid- donates H1+ Base- accepts H1+ Conjugate base- what becomes of the acid after donating H1+ Conjugate acid- what the base becomes after accepting an H1+ • Acid- has H1+ ions in it • Base- has OH1- ions in it

39. Neutralization of Acids & Bases • MAVA = MBVB