Week 2 Chem Notes
Week 2 Chem Notes CHM2045
Popular in Chemistry 1
verified elite notetaker
Popular in Chemistry
This 5 page Class Notes was uploaded by Moira Notetaker on Sunday January 3, 2016. The Class Notes belongs to CHM2045 at University of Florida taught by George Gower in Fall 2016. Since its upload, it has received 39 views. For similar materials see Chemistry 1 in Chemistry at University of Florida.
Reviews for Week 2 Chem Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 01/03/16
CHM2045 Gower 1-(11-13-14)-16 Week Two Notes Ions Atom or atoms that have a net positive or negative charge o Polyatomic ions-molecule with a charge Cation-ion with positive charge Example cation: o Occurs when a neutral atom loses valence electrons Na- 11 protons, 11 electrons o Usually are metals Na - 11 protons, 10 electrons Anion- ion with negative charge Example anion: o Occur when a neutral atom gains electrons Cl- 17 protons, 17 electrons o Usually nonmetals Cl 17 protons, 18 electrons Periodic Trends for Ion Charge Group 1- becomes 1+ cation Group 2- becomes 2+ cation Group 3- becomes 3+ cation Group 4- varies depending on atom, can be 4+ cation or 4- anion Group 5- becomes 3- anion Group 6- becomes 2- anion Group 7- becomes 1- anion Group 8- does not becomes ion because it has a full octet of valence electrons How many electrons and protons in 213Al? 13 electrons, 13 protons (14 neutrons) 27 3+ How many electrons and protons in 13Al ? 10 electrons, 13 protons (14 neutrons) How many electrons and protons in 734Se ?- 36 electrons, 34 protons, (44 neutrons) Monoatomic ions- have only one atom o Na , Cl , Ca , O , Al , N 3- Polyatomic ions- have more than one atom o OH , CN , NH ,4NO 3 Nomenclature of Polyatomic Ions (Covalently Bonded) - HCO i3 bicarbonate HSO i4 hydrogen sulfate (bisulfate) CH 3O i2 acetate - ClO 4s perchlorate NO is nitrate 3 ClO 3s chlorate - NO 2s nitrite ClO 2s chlorite - MnO i4 permanganate ClO is hypochlorite CN is cyanide - OH is hydroxide CO 32-is carbonate 2- O 2 is peroxide SO 42-is sulfate 2- CrO 4 is chromate 2- SO 3 is sulfite Cr2O 72-is dichromate 2- S2O 3 is thiosulfate HPO 42is hydrogen phosphate 3- PO 4 is phosphate 3- AsO 4 is arsenate BO 33-is borate Note: Ions ending in”-ite” usually have less atoms than ions ending in “-ate” o e.g. Nitrate (NO ) 3s Nitrite (NO ) 2 Molecules vs Formula Units Covalent substances are molecules consisting of individual (usually nonmetal) molecules Ionic substances are formula units of a continuous lattice of charged ions Ionic Compounds Combination of cation and anion (anion [nonmetal] gets the ending “-ide”) Combination of metals and nonmetals o Formula always contains lowest whole number ratio of ions o Sum of the charges must always be zero Formula of Ionic Compounds 3+ 2- Al combines with O = Al O 2 3 Na combines with Cl = NaCl CaBr 2s Ca 2+and Br - + 2- Na 2O i3 Na and CO 3 BaCl 2s barium chloride Li2O is lithium oxide Mg(OH) is2magnesium hydroxide KNO i3 potassium nitrate (NH 4 2O i3 ammonium carbonate Note: There is no prefix of ionic compounds. There is also no “-ide” added to molecular compounds. More on Ionic Compounds: When naming transition metals, Roman numerals are used to show the charge that the metal has (since sometimes one transition metal can have differently charged ions) o FeCl 2s Iron(II) chloride (you can usually tell the charge on the cation based on the number of atoms in the anion) o FeCl 3s Iron(III) chloride o Cr 2 3s Chromium(III) sulfide o REMEMBER- the greater the cation charge, the more tightly the anion is bound to it o The merging of ions gives off a lot of energy!!! Arrhenius Acids Substance that yields H ions when dissolved in water HCl- pure substance hydrogen chloride o Dissolves in water to make hydrochloric acid o If hydrogen is the first element in a chemical formula without oxygen, then the prefix is “hydro-“ Oxoacid is an acid with hydrogen, oxygen, and one more element o Hydronitric acid (HN) vs Nitric acid (HNO 3 o For anion in oxoacid- “-ate” ending turn to “-ic” ending o For anion in oxoacid- “-ite” ending becomes “-ous” ending o Naming oxoacids will be on quizzes, but not exams Binary acids- hydrogen+ one other element= hydro____ic acid Arrhenius Bases - Substance that yields OH ions when dissolved in water NaOH- sodium hydroxide KOH- potassium hydroxide Ba(OH) 2 barium hydroxide NH OH- ammonium hydroxide 4 Side note- all the aforementioned bases are poisonous. Hydrated Ionic Compounds (Hydrates) Ionic compound that absorbs water o Each formula unit of the compound has a certain number of H O 2 molecules o Hydrates are the only ionic compounds with prefixes 1 H2O molecule per formula unit- monohydrate 2- dihydrate 3- trihydrate 4- tetrahydrate 5- pentahydrate 6- hexahydrate 7-heptahydrate 8- octahydrate 9-nonahydrate 10-decahydrate o BaCl 22H 2- barium chloride dihydrate o LiCl*H2O- lithium chloride monohydrate Heat makes the water molecules evaporate and the compound becomes an anhydrous Note: Mass of hydrate-mass of anhydrous compound= mass of water molecules o X=(mol H O2/(mol of ionic compound) Functional Groups Organic chemistry- branch of chemistry dealing with carbon compounds Carbon compounds are both a molecule and a compound o If it has an OH molecule, then it is an alcohol(methanol) o Methyl amine has an NH mol2cule o Acetic acid has two C atoms and an O and OH atom o Alkenes are recognized by their standard formula: C H n (2n+2) Moles 23 1 mole= N =A6.022 x 10 (Avogadro’s Number) o Units for Avogadro’s number are mol , formula units, particles, molecules, atoms, electrons, protons, or neutrons Molar mass=atomic mass for each element (e.g. H=1.008, O=15.998, Cl=35.45, etc) Amu(atomic mass unit)=g/mol (grams divided by moles) REMEMBER- isotopic abundance determines atomic mass and it usually is only shown in up to 4 sigfigs How many atoms in 0.551g of potassium? 0.551g K x (1 mol K/39.10g K) x (6.022 x 10 23atoms K/ 1 mol K) = 8.486 x 10 21 atoms Molar mass of molecules (g/mol)= atomic mass x coefficient o For monoatomic element, coefficient is 1 o For diatomic element, coefficient is 2 Diatomic elements- H, N, O, F, Cl, Br, I Example: Cl molar mass = 35.45 g/mol Cl2molar mass = 70.90 g/mol Molecular Mass Sum of all molar masses in a molecule Molecular mass in amu = molar mass in grams o E.g. H 2- molecular mass of 18.02amu and molar mass of 18.02g Molar Ratios 1 mole of H O 2 2 moles of H, 1 mole of O Molar ratio of H:O= 2:1 Molar ratio of O:H= 1:2 How many moles of H in 25g of H O? 2 25g of H O2x (1 mol H O/12.02g H O) x (2 mol H/1 mol H O) = 2.7752mol H REMEMBER- Don’t apply sigfigs until the end of the problem! How many H atoms in 72.5g of C H O? 3 8 72.5g C H3O 8 (1 mol C H O/3608095g C H O) x 38 8ol H/1 mol C H O) x (6.023 8 x 10 23atoms H/1 mol H) = 5.81 x 10 atoms of H Formula mass- sum of atomic masses in a formula unit of an ionic compound o E.g. NaCl= 58.44 g/mol = 58.44 amu What is the formula mass of Ca (PO )3? 4 2 301.18 amu Mass Relationships Mass percent: (Mass of certain element in compound/Total mass of compound) x 100 Also called percent composition What mass of N O i2 n4trogen? (28.014g N/92.006g N O ) x 100 = 30.45% N 2 4 How many grams of N are in 15g of N O ? 2 4 15g N O x (1 mol N O /92.006g N O ) x (2 mol N/1 mol N O ) x (14.007g N/1 2 4 2 4 2 4 2 4 mol N) = 4.567g N (4.567g N/15g N O )2x 400 = 30.45% N Molecular formula- exact number of atoms of each molecule in the smallest unit of substance Molecular formula is still the actual substance Empirical formula- shows simplest whole number ratio of atoms in a substance o E.g. Molecular formula of sugar: C H O 6 12 6 o Empirical formula of sugar: CH O (a2tually molecular formula for formaldehyde)
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'