Chem week 4
Popular in Chemistry: Principles and Applications
Popular in Chemistry
This 5 page Class Notes was uploaded by Catherine Carter on Thursday September 22, 2016. The Class Notes belongs to CHE 105 at University at Buffalo taught by Melvyn Churchill in Summer 2015. Since its upload, it has received 5 views. For similar materials see Chemistry: Principles and Applications in Chemistry at University at Buffalo.
Reviews for Chem week 4
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: 09/22/16
solubility rules o simple salts of alkali metal ions and the ammonium cation are soluble o simple nitrates are soluble o simple chlorates are soluble o simple acetates are soluble o most chlorides are soluble (except with Ag, Pb, Hg2) o Bromides and Iodides behave similarly o most sulfates are soluble except (Ag2, Pb, Hg,Ca, Sr, Ba) Insolubility Rules o carbonates (except Na, K, etc. and NH4) o phosphates (except Na, K, etc. and NH4) o sulfides (except Na, K, etc. and NH4 and Ca, Sr, Ba) Nature of Acids o Acids increase the concentration of H+ when dissolved in water (Arrhenius Theory) o Acids are Proton donors (BronstedLowry Theory) o have a sour taste o turn litmus paper red o react with active metals liberating H2 o react with carbonates liberating CO2 o strong acids completely dissociated in water (strong refers to the dilution concentration) hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, sulfuric acid, chloric acid, perchloric acid o weak acids: acetic acid, hydrofluoric acid, phosphoric acid Nature of Bases o increase the concentration of OH when dissolved in water (Arrhenius Theory) o Bases are Proton acceptors (BronstedLowry Theory) o bitter taste o slippery, soapy feel o turn litmus paper blue o strong bases completely dissociate in water (strong refers to its dissociation) alkali metal hydroxides, alkaline earth metal hydroxides (calcium hydroxide is not very soluble but the amount that does dissolve completely dissociates o weak bases react only partially with water like ammonia AcidBase reactions >the acid donates a proton (H+) to the base o it is a neutralization reaction, the products are a salt and water o write out the net ionic equation to see what exactly happens o some reactions give off a gaseous product like CO2 and SO2, other reactions can give the expected product but in the gaseous phase (H2S) Oxidation Reduction Reactions (aka Redox reactions) o oxidation is when and atom or ion loses electrons o reduction happens when an atom or ion gains electrons o LEOGER (Lose Electrons Oxidation, Gain Electrons Reduction) o can be broken down into “half reactions” this then has to be balanced to you multiply the first equation by 2 then add the two and cancel the things that are EXACTLY the same on both side (usually just the electrons) and that is your reaction you will need to assig an oxidation number to each element in a compound or charge entity (it’s only redox if one gains and another loses electrons) elements in their elemental form have an oxidation state of 0 the oxidation number of any monoatomic ion is the same as its charge metals have positive states nonmetals have negative when combined with metals nonmentals will have a positive state when combined with more electronegative nonmetals Flourine is the most electronegative and has a state of 1 (So does the rest of its group oxygen almost always has an oxidation number of 2 (peroxide ion 2,superoxides 1(the individual oxygen atoms have half of the charge in the pairing) hydrogen is either + or – 1 the sum of the oxidation numbers in a neutral compound is zero and in a polyatomic ion it equals the charge on that ion o metals are oxidized by acids to form salts and can be oxidized by salts of other metals Displacement reactions o Type 1: a metal displaces a “less active” metal in a salt o the more active metal goes into the solution as a cation a cation oxidizes an element and an element reduces a cation o o those above H are more likely to react with an acid and those below are highly unlikely to react with an acid o Type 2: involve the displacement of a halogen. a more active halogen displaces a less active halogen from a salt activity of the halogens correlates with the electronegativity o disproportionate reactions occur when one element is simultaneously oxidized and reduced Balancing redox reactions, oxidation state method o identify the atoms that are being reduced and oxidized o balance the atom types that change oxidation state o calculate the change in oxidation state for these o balance total increase and total decrease in oxidation state o balance numbers of other atoms by inspection for aqueous ionic equations (acidic/neutral conditions) balance O by adding H2O to the O deficient side of the equation balance H by adding H+ to the H deficient side of the equation simplify and check your answer for basic solutions balance O by adding H2O to the O deficient side balance H by adding H= to the H deficient side add the same amount of OH to both sides simplify and check two solutions can contain the same solute but be different because of the difference in concentration (Molarity (M)) o o dilution does not change the number of moles of solute in solution o o the molarity can be used in stoichiometric equations because it is mole/liters and can be converted to just moles and then to grams helps to write moles/liter during calculations instead of M titration can be used to calculate to concentration of a solute in a solution o to titrate an acid, you put a basic indicator in the solution then slowly add the base to the acid (drop by drop) once it reaches the endpoint it is a basic solution o use a known concentration of base and measure volume used to find the concentration of the acid that was in solution o the same can be done with basic solutions using an acidic indicator and adding acid of a known concentration to the solution o when the moles of H+ = the moles of OH that is the equivalent point and is when the indicator changes color o need to write out the equations to ensure accuracy Redox titrations o instead of looking at H+ and OH you look at the electron transfer, you don’t always need to have an indicator because they undergo an obvious color change when oxidized or reduced o Gravimetrical analysis o dissolve unknown substance in water o react unknown with known substance to form a precipitate o filter and dry precipitate o weigh precipitate o use chemical formula and mass of precipitate to determine amount of unknown ion o the mass of the component of interest can be calculated by: o
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'