HN ADV CHEMISTRY CHAPTERS 1- 4

• 2 fundamental concepts of chemistry• 1. Matter is composed of various types of atoms• 2. One subs changes into another by reorganizing the way the atom are

attached to each other

• The SI System pg 8 & 9• Table 1.1 base units• Table 1.2 prefixes • Uncertainty in Measurement• numbers obtained by using some measuring device• #’s that are the same regardless of who makes the measurement certain

digits• last digit is estimated and varies w/the person who makes the measure

uncertain digits

Chapter 1: Chemical Foundations

• all #’s have some degree of uncertainty amt depends on precision of device • significant figures/digits – all certain digits and the first uncertain digit

• Pg 11 Sample exercise 1.1 • Significant Figures and calculations • pg. 13 rules for counting sig figs• pg. 14 rules for sig figs in calculations and rounding

• Precision & Accuracy• accuracy – agreement of a value w/the true value• precision – degree of agreement among several measurements of the same

quantity – how close #’s are to each other• Types of error• 1. random error – (indeterminate error) – measurement has an equal

probability of being high or low• 2. systemic error – (determinate error) – occurs in same direction each time

• Dimensional Analysis• used to convert one unit to another• uses conversion factors in ratio (want/have) – multiply by the #’s

on top of ratio and divide by #’s on the bottom – make sure all units cancel until the last un-cancelled unit matches the unit of the answer

• Density - ratio of a subs mass to its volume• D = m

v

• Chapter 2: Atoms, Molecules and Ions

• Chemical Laws• 1. Law of Conservation of Mass – mass is neither created nor destroyed it only changes form• 2. Law of Definite Proportions – a given cmpd always contains exactly the same proportion of elements by mass proposed by Proust – Dalton proposed that matter is composed of atoms so a cmpd contains atoms in the same proportions• 3. Law of Multiple Proportions – when 2 elements form a series of cmpds, the ratios of the masses of the 2nd element that combine w/1 g of the 1st can always be reduced to small whole #’s

• Pg 42 Sample exercise 2.1

• 4. Avogadro’s hypothesis – at the same temp & pressure, equal volumes of different gases contain the same # of particles

• Subatomic Particles Mass Charge• Electron 9.11 x 10-31 kg -1• Proton 1.67 x 10-27 kg +1• Neutron 1.67 x 10-27 kg none

One atom turns to another and says, “Darn it. I’ve lost an electron!” The other atom says, “Are you sure?” and the first says, “I’m positive!”

• Molecules and Ions• - chemical bonds – forces that hold atoms together• - covalent bonds – e- shared – particle formed called a molecule –• molecules represented by chemical formula or structural formula• - ionic bonds – particles exchange e- to form charged particles ions

(+) ion = cation (-) ion = anion

Chapter 3: Stoichiometry

• Atomic masses - based on 612C as std – mass = 12 amu

• - mass spectrometer is used to compare masses of atoms• - given on periodic table avg atomic mass of all naturally occurring isotopes• - can use a mass spec to determine the isotopic composition of a natural element

• Pg 81 Sample exercise 3.1

• The Mole• - the # of C atoms in exactly 12 g of pure 6

12C = 6.02214 x 1023 6.022 x 1023 = Avogadro’s #• *doesn’t matter what the subs is it is still = Avogadro’s # • Pg 83 Sample exercise 3.2• Pg 84 Sample exercise 3.3• Pg 85 Sample exercise 3.4, 3.5

• Molar mass• - the mass in grams of one mole of a cmpd – the sum of all the atomic masses multiplied by the subscripts

• Pg 86 Sample exercise 3.6, 3.7• Pg 88 Sample exercise 3.8

• Percent composition• - compare the mass of each element to the total mass of the cmpd mass percent

• Pg 89 Sample exercise 3.9 • Determining the formula of a cmpd• - need to determine the % mass of each element in the cmpd• - empirical formula – smallest whole # ratio of elements in a cmpd• - molecular formula – some multiple of the emp. formula based on the ratio

Molecular molar mass = multiple of Empirical molar mass empirical

• Pg 93 Sample exercise 3.11

• Chemical equations• - depict chem rxns• - Reactants Products

• - bonds have been broken and reformed to produce new subs• - must show that all atoms in reactants are accounted for in products by balancing equation (law

of conservation of matter)• - shows states of matter• - shows # of atoms/molecules in rxn• - shows # of moles of R and P in rxn

• Pg 100 Sample exercise 3.14

• Stoichiometric Calculations:• 1. Balanced equation• 2. State given• 3. State what is wanted• 4. Convert given to moles• 5. Mole to Mole ratio (from balanced equation)• 6. Convert to units of answer

• Pg 105 Sample exercise 3.16, 3.17 • **any step not needed just SKIP • Limiting Reactants • - the reactant consumed firsts limits the amt of product formed• - to determine the LR do a stoichiometry problem starting w/1 R and end w/the other - compare to amts given• - to determine amt of product start w/LR and end w/product

• Pg 110 Sample exercise 3.18

• Percent yield• - amt of product formed when a reactant is completely consumed is called the theoretical yield• - amt of product formed in reality is called the actual yield• - these can be used to determine the % yield • Actual x 100 = % yield• Theoretical • Pg 111 Sample exercise 3.19

Chapter 4: Types of Chemical Reactions and Sol’n Stoichiometry• - Water H H• - able to dissolve many things 105o

• - bent• - O-H bonds are covalent bonds O• - e- shared unequally – oxygen has a greater pull on e- so they are closer to it

H b/c e- are farther away from it polar molecule • Hydration – ionic solid dissolving in H2O

• - (+) of H2O is attracted to anions of cmpd

• - (-) of H2O is attracted to cations of cmpd• - salt “falls apart” – breaks into ions and is indicated w/the (aq) • Some non-ionic cmpds are soluble in H2O polar dissolves polar and nonpolar

dissolves nonpolar

• Sol’ns• - made up or solutes and solvents• - some can conduct electricity electrolytes• - strong electrolytes – conduct efficiently• - weak electrolytes – conduct poorly• - non-electrolytes – do not conduct• - conductivity is a factor of how many ions are present in a sol’n• - strong electrolytes ionize completely• - soluble salts are easily hydrated• - strong acids produce H+ and other ions• - all form (aq) sol’n• - completely dissociate into ions• - exception: H2SO4 , only 1 H+ dissociates• - strong bases release OH- from cations

• - weak electrolytes have only a small amt of ionization• - weak acids contain an acidic H+ and nonacidic H’s – ex: H3PO4

• - weak bases partially lose OH- in sol’n • - nonelectrolytes – dissolve in H2O but do not produce any ions

• Composition of sol’ns• - need to know 2 things to do Stoichiometric calcs• 1. nature of reactants• 2. amts of chem in sol’n

• - Molarity – (M)• - expression of sol’n concentration • M = moles of solute• L of sol’n • Pg 134 Sample exercise 4.1, 4.2, 4.3• Pg 135 Sample exercise 4.4, 4.5

• Std sol’n – sol’n whose conc. Is accurately known

• Pg 136 Sample exercise 4.6• • Std sol’n – sol’n whose conc. Is accurately known

• Pg 136 Sample exercise 4.6

• Dilutions• - sol’ns are purchased in conc. form and H2O is added to desired molarity

• M1V1 = M2V2

• - when solving for volume of conc. sol’n, remember that H2O must be added to reach the total volume

needed

• Pg 138 Sample exercise 4.7

• Types of Chem Rxns• - Precipitation Rxns – 2 sol’ns are mixed and a solid forms and separates from sol’n(precipitate, ppt)• - products must have a net charge of 0 – (+) = (-)• - rules for determining solubilities on pg. 144 Table 4.1• - slightly soluble – a tiny amt of solid dissolves (not noticeable) sometimes insoluble

• Pg 144 Sample exercise 4.8

• - equations so far have been molecular equations – do not show what is happening b/n particles in the sol’n

• Ex: K2CrO4(aq) + Ba(NO3)2(aq) BaCrO4(s) + 2KNO3(aq)

• - complete ionic equations – all subs that are strong electrolytes are represented as ions • Ex: 2K+

(aq) + CrO42-

(aq) + Ba2+ (aq) + 2NO3- (aq) BaCrO4(s) + 2K+ (aq) + 2NO3

- (aq)

• *not all ions participate in the rxn spectator ions, e.g. K+ NO3

-

• - net ionic equations – includes only those ions that participate in rxn • Ex: Ba2+

(aq) + CrO4 2-

(aq) BaCrO4(s)

• Pg 146 Sample exercise 4.9 • Stoichiometry of ppt rxns• - must decide what will occur when 2 sol’ns are mixed – write down species (ions) in sol’n• - to obtain moles of reactants use volume of sol’n and Molarity • Pg 147 Sample exercise 4.10• *Steps (1-6) pg 148 • Pg 148 Sample exercise 4.11 • Acid-base rxns• - according to Bronstead-Lowry• - acid is a proton (H+) donor• - base is a proton (H+) acceptor

• *OH- is such a strong base that for stoichiometry calcs. It can be assumed to react completely w/any weak acid

• - rxn is called a neutralization rxn • Pg 150 Sample exercise 4.12• Pg 151 Sample exercise 4.13

• Acid-base titrations• - volumetric analysis – technique for determining the amt of a certain subs by doing a titration -

titration – delivery (from a buret) of a measured volume of a sol’n a known conc. (the titrant) into a sol’n containing the sub being analyzed (the analyte) - when exactly enough titrant has been added to react w/the analyte called the equivalence point or stoichiometric point*marked by an indicator – a subs that changes color according to pH

• - point at which indicator changes color called the endpoint• *you need to choose an indicator that changes color at the equivalence point

• Requirements for successful titration:• 1. Exact rxn b/n titrant and analyte must be known• 2. Stoichiometric/equivalence point must be marked accurately• 3. Volume of titrant required to reach Stoichiometric point must be known• *Use strong acids/bases for titrant • Standardizing the sol’n • Pg 153 Sample exercise 4.14, 4.15

• Redox rxns• - one or more e- are transferred b/n subs• - most energy producing rxns are redox rxns• - oxidation states/oxidation #’s – help track e- in redox rxns• *Rules for assigning oxidation #’s pg 156 Table 4.2 • Pg 157 Sample exercise 4.16

• **Exception: +2/3 -2• Fe O4 - b/c it’s an “avg”• +8 -8 - some Fe’s are 2+ and some are 3+

• *occurs in other cmpds DON’T FREAK!! • -4+1 0 +4-2 +1-2• Ex: CH4 + 2O2 CO2 + 2H2O • Oxidation loss 8e- RA• Reduction gained 2e- OA

• *if a subs is reduced it ------------------------------------------- *if a subs is oxidized itcauses oxidation in the -7-6-5-4-3-2-10+1+2+3+4+5+6+7 causes reduction in the other oxidizing agent other reducing agent

gain of e- loss of e- reduction oxidation

• pg 160 Sample exercise 4.17• Pg 161 Sample exercise 4.18

• Balancing Redox Rxns• - use half-rxn method• - separate into one for oxidation and one for reduction • Ex: Ce4+ + Sn2+ Ce3+ + Sn4+

• Reduction Oxidation• Ce4+ Ce3+ Sn2+ Sn4+

• 2[1e- + Ce4+ Ce3+] Sn2+ Sn4+ + 2e-

• 2e- + 2Ce4+ 2Ce3+ Sn2+ Sn4+ + 2e-

• 2Ce4+ + Sn2+ 2Ce3+ + Sn4+ • 2(4+) + 2 2(3+) + 4• +10 +10 • *pg 162 Steps for balancing Redox rxns using half rxns

• +7 -2 +2 +3 +2• Ex 2: MnO4

- + Fe2+ Fe3+ + Mn2+

• Reduction Oxidation• MnO4

- Mn2+ Fe2+ Fe3+

• 8H+ + MnO4- Mn2+ + 4H20

• 5e- + 8H+ + MnO4- Mn2+ + 4H2O 5[Fe2+ Fe3+ +1e-]• 5Fe2+ 5Fe3+ + 5e-

• 8H+ + MnO4

- + 5Fe2+ Mn2+ + 4H2O + 5Fe3+

• +17 +17 • Pg 165 Sample exercise 4.19 • - redox rxns can also occur in basic sol’ns

• Pg 167 Sample exercise 4.20 (in basic sol’n)