Chem 105 a Week 4 Notes
Chem 105 a Week 4 Notes CHEM 105A
Popular in General Chemistry
verified elite notetaker
Popular in Chemistry
This 5 page Class Notes was uploaded by Emma Morrissey on Friday September 16, 2016. The Class Notes belongs to CHEM 105A at University of Southern California taught by Thomas Michael Bertolini in Fall 2016. Since its upload, it has received 33 views. For similar materials see General Chemistry in Chemistry at University of Southern California.
Reviews for Chem 105 a Week 4 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 09/16/16
12 Sept 2016 Lecture Chapter 4: Stoichiometry (Skip gas-forming reactions) ● Stoichiometry ○ Calculating quantities of reactants and products in a chemical reaction ○ Based on the law of conservation of mass ○ The amounts of any other substance in a chemical reaction can be determined from the amount of just one substance ● Percent Yield ○ Theoretical yield ■ The maximum amount of product that can form during a reaction (the calculated amount) ○ Actual yield ■ The amount of pure product collected from a reaction (the measured amount/ the experimental result) ○ Percent yield = (actual/theoretical)x100% ● Limiting Reactant ○ Sometimes all reactants are completely consumed, sometimes one is in excess ○ A limiting reactant is consumed first, preventing further product formation ○ Always determine limiting reactant for stoichiometry problems 14 September 2016 Lecture ● Some Definitions ○ Solution- homogeneous mixture ■ Ex: Sugar water ○ Solvent- the majority solution component, retains its state ■ Ex: Water ○ Solute- the minority solution component, becomes the state of the solvent ■ Ex: Sugar ○ Salt- any ionic compound ○ Note that solutions can be solids, liquids, or gases ● Solution Concentration ○ Molarity (M) ○ Moles of the solute divided by the litres of solution ● Dilution ○ Common to make diluted solutions from stock solutions ○ For dilutions, more solvent is added but the amount of solute remains the same ■ Mol solute does not change ● Electrolytes ○ An electrolyte is a substance that when dissolved in water produces a solution that conducts electricity ■ Ionic compounds dissolved ○ Nonelectrolytes dissolve in water but do not ionize ■ Covalent compounds ○ Conductivity is a qualitative measure of the degree to which a solution ionizes ■ Strong electrolytes conduct a strong current ■ Weak electrolytes conduct a weaker current ■ Nonelectrolytes do not conduct currents ● Strong electrolytes ○ Ionize completely in solution ○ Soluble salts ( NaCl, KBr, LiNO3, etc) ○ Strong acids (HCl, HNO3, H2SO4, HClO4, HBr, HI) ○ Strong bases (NaOH, KOH) ● Weak electrolytes ○ Slightly ionize in water ○ Weak Acids: HC2H3O2 ○ Weak bases: NH3 16 September 2016 Lecture ● Poisoning 101 ○ An ideal poison is ■ Easily obtainable ■ Potent (Alexander Litvinenko) ■ Odorless, tasteless ■ Water Soluble ● An Actual Poisoning Case ○ 1988: A murderer tried to kill an entire Florida Family by leaving bottles of poisoned coca cola on their doorstep ○ The father drank a small amount of soda with whiskey so he had little health effects ○ Mother and son were affected ○ Daughter only drank diet, so was not affected ○ Thallium Nitrate ● Solubility Rules ● Precipitation reactions ○ Swap the anions and cations in the product ○ If one of the products is insoluble, it is a precipitate ○ If there is no precipitate, there is no reaction; the solution remains solely ions ● Precipitation ○ Magnesium ions and natural soap (sodium stearate) form soap scum ○ Detergents (synthetic soaps) are more soluble ● Writing Chemical Equations for Solutions ○ Molecular Equation ■ Reactants and products are written as compounds ○ Complete ionic equations ■ All strong electrolytes are written as ions ○ Net ionic equation ■ Species that are the same on both sides of the equation are removed ● Acid-Base reactions ○ Acid ■ Produce H+ ions in water ○ Base ■ Produce OH- ions in water ○ Acid- base rx ● ● ● Acid-base titrations ○ Titration is the analysis of the amount of a substance by reaction with a solution of known concentration ○ Titration stoichiometry uses moles of acid vs moles of base or vice versa