AICE Chapter One Monatomic ions- ions formed from a single atom Binary compounds- compounds composed of two elements Nomenclature- naming system of binary ionic compounds involves combining the names of the compound’s positive and negative ions ionic compounds (flash card) *made of metal and nonmetal (or polyatomic ions) *ionic bonding *formula units for representative particles molecular compounds (flash card) * nonmetals only *covalent bonding *molecules for representative particles naming ionic compounds (flash card) 1. name first element 2. name second element, change ending to -ide *never change ending of polyatomic ion *cation (which is the metal, unless it is ammonium) with more than one possible charge must have roman numeral. (Roman numeral equals the charge of the cation) naming molecular compounds (flash card) 1. name first element 2. name second element, change ending to -ide *must use prefixes for subscripts. Exceptions for prefixes--> 1. no mono for first element 1. a 2 syllable prefix, added to a vowel, drop vowel on prefix CO = carbon monoxide (illustrates both rules) writing molecular formulas (flash card) *prefixes give you the subscripts writing formula units (flash card) *overall positive and overall negative charges must cancel out, be neutral, which means numerically it is zero for the final charge. (use George) *if you add a subscript to polyatomic ion you must use ( ). Or stated another way if you have more than one of a polyatomic ion you must add ( ). How do you know when you have a polyatomic ion? (flash card) 1. you see ( ) 2. -ate or -ite (exceptions ammonium, cyanide, and hydroxide) 3. ionic with 3 or more capital letters. When does a cation need a Roman numeral? (flash card) *when it has more than one possible charge, which means it is not in IA, IIA, IIIA or one of the 3 exceptions ---> silver, cadmium, and zinc. Naming acids (flash card) *anion ends in –ide = add hydro- change ending to –ic and acid *anion ends in –ate = change ending to –ic and acid *anion ends in –ite = change ending to –ous and acid Writing formula for acid (flash card) work backwards with rules to get anion cation is always H+ make compound neutral. Percent Composition- the percentage by mass of each element in a compound percent composition (flash card) 1) find molar mass 2) divide the mass of each element in the compound by the molar mass of compound 3) change to percent by multiplying by 100% *to make sure they add up to 100% do all % but one, subtract all others from 100 % to solve for last one. Formula mass- sum of the average atomic masses of all atoms represented in its formula Empirical formula- consists of the symbols for the elements combined in a compound with subscripts showing the smallest, whole number mole ratio of the different atoms in the compound. *The molecular formula gives the actual number of atoms of each element in a molecular compound. empirical formula (flash card) * if given % assume 100 grams 1) change all given to moles 2) divide all moles by the smallest number of moles--> becomes mole ratio .9XXX round up and .0XXX round down 3) mole ratio gives you subscripts *must be whole numbers so .2 x 5 .25 x 4 .333 x 3 .5 x 2 .666 x 3 molecular formula (flash card) * must have empirical formula to begin 1) divide molar mass by empirical mass which equals multiple (empirical mass = mass of empirical formula) 2) multiple X empirical formula = molecular formula Molarity (M) M= moles of solute / liters of soln. Preciptation: is the process in which ions leave a solution and regenerate an ionic solid. *when two different ionic solutions are mixed, all precipitates may form their ions from the two solutions reacting to form an Net Ionic Equation- includes only those compounds and ions that undergo a chemical change in a reaction in an aqueous solution Spectator Ions- ions that do not take part in a chemical reaction and are found in the solution both before and after a reaction. Solubility rules= tells us which ions are soluble or insoluble in the presence of each other. Solubility rules say…. Phase symbol Precipitation Soluble (aq) No insoluble (s) yes --> To go from molecular equation (what we did normally do) to (complete) ionic equation you break up all aqueous items into ions. If the subscript was assigned by George it gets pulled out in front and becomes a coefficient. --> To go from complete ionic to net ionic equation you remove the spectator ions. Spectator ions are identical on both sides of the complete ionic equation. Spectator ions do not make the solid precipitate. Nature of Chemical Reactions -A chemical reaction is a process in which one or more substances is converted into new substances with different physical and chemical properties. -reactant- a substance that enters into a chemical reaction -product- a substance that is produced by a chemical reaction *Chemical reactions are represented by sentences known as chemical equations. *On the left side (reactant side) if there is a ‘+’(plus), it means ‘reacts with’. If the plus is on the right (product side) it is read as ‘and’. -The arrow (-->) between the products and the reactants is read as ‘yields’ Indications of a chemical reaction 1). Evolution of energy as heat and light 2). Production of a gas 3). Formation of a precipitate- a solid that is produced as a result of a chemical reaction in solution and that separates from the solution 4). Color change- sometimes Characteristics of chemical equations 1). The equation must represent known facts 2). The equation must contain the correct formulas for the reactants and products 3). The Law of Conservation of Mass must be satisfied Coefficient- a small whole number that appears in front of a formula in a chemical equation. -A coefficient is the number written before the formula for a substance in a balanced chemical equation to represent the quantities of reactants and products involved in the chemical reaction *one is never written but understood as a coefficient. Word equation- an equation in which the reactants and products in a chemical reaction are represented by words Formula equation- represents the reactants and products of a chemical reaction by their symbols or formulas Reversible reaction- a chemical reaction in which the products reform the original reactants The Reason for Reactions *Chemical reactions occur so that atoms can become more stable, like a noble gases, isoelectronic to them. They want low potential energy. Significance of Chemical equations 1. Coefficients give relative amounts of reactants and products. 2. The relative masses of the reactants and products of a chemical reaction come from the coefficients. 3. The reverse reaction has the same relative amounts of substances as the forward reaction. Balancing Chemical Equations -For mass to remain constant before and after a chemical reaction, the number of atoms of each element must also remain the same before and after -Because the number and kind of atoms on the reactant side are the same as the number and kind of atoms on the product side, a balanced chemical equation demonstrates the conservation of matter. Balancing chemical equations ------Uncle D’s Hints 1. Do metals first. 2. Then do polyatomic ions. If they appear on both sides treat as a unit. If not on both sides you must treat them as separate elements. 3. Then nonmetals, but save H and O for last. 4. When doing H and O (last), do the easier of the two first. This will always be the one that appears the fewest times. (literally as a capital letter.) *when it appears only twice, you balance using the lowest common multiple. X -if you unbalance an element previously balanced, fix it ASAP. Coefficients vs Subscripts SUBSCRIPTS FORMULAS WHAT THEY ARE BEHIND COEFFICIENTS BALANCE EQUATIONS AFFECT EVERYTHING IN FORMULA THEY ARE IN FRONT OF * coefficients and subscripts get multiplied by each other when seen together for the same formula. Types of Reactions 1) Direct Combination Reactions- When two or more reactants come together to form a single product. (A+B-->AB) (synthesis) Hint = one product 2.)Decomposition Reactions- Reaction in which a single compound is broken down into two or more smaller compounds or elements (AB--> A+B) (opposite on direct composition. Hint= one reactant. 3.)Single Replacement Reaction- When an uncombined element displaces an element that is part of a compound. (A+BX--> AX+B) (A replaces B, the more active element will replace a less active element, ALWAYS) Hint = element + compound on both sides. 4.)Double Replacement Reaction- atoms or ions from two different compounds replace each other. (AX+BY--> AY+BX) Hint = 2 compounds on both sides *For a Double replacement reaction to occur, one of the products must be...... 1. a solid 2. a gas 3. or a molecular compound 5.)Combustion- oxygen gas added as a reactant. burning of an organic substance, the product is either: CxHyOz +O2-->CO2+ H2O (complete) or, CxHyOz + O2-->CO+H2O (incomplete) Activity Series- a list of elements organized according to the ease with which the elements undergo certain chemical reactions. *for one element to replace another it must be more reactive. (translates to ---> higher on the chart) page 286. *used mainly for single replacement reactions. Composition stoichiometry- deals with the mass relationships between elements in a chemical compounds. Reaction stoichiometry- involves the mass relationships between reactants and products in a chemical reaction Chemical measurements *Atomic mass- mass of an atom expressed relative to the mass assigned to carbon-12 *Formula mass- the sum of the atomic masses of all the atom in a compound (mass of an ionic compound) * The problem is stoichiometry if you are given the quantitiy of one substance, asked for the quantity of another substance, and you have a balanced equation with both in it. *A mole of any element is the number of atoms of that element equal to the number of atoms in exactly 12.0g of Carbon-12. ~A mole is the amount of substances that contains 6.02 x 1023 particles. ~The number of particles in a mole of a substance is known as Avogrado’s number constant. MASS Representation Particles Atomic Mass Element Atoms Formula Mass Ionic Compound Formula unit Molecular Mass Molecular Compound Molecules Ionic Mass Ions Ions *The mass in grams of 1 mole of a substance is called the molar mass of the substance. Mole ratio- is a conversion factor that relates the amounts in moles of any 2 substances involved in a chemical reaction. ---> uses the coefficients. *Because the mole measures both a mass and a number of particles (a volume of a gas) it is the central unit in converting the amount of a substance from one type of measurement to another. *The volume of one mole of any gaseous substance at standard conditions is called the molar volume. The molar volume of a gas at 0oC and one atmosphere of pressure is 22.4 liters. *STP-Standard temperature and pressure which is 0oC and 1 atm *The coefficients in a balanced chemical equation represent the relative number of moles of each substance. This molar ratio can be used to analyze a chemical reaction more closely and to determine any reactant or product given the number of moles of any other reactant known as mole-mole problems. *Mole calculations can be used to verify that mass is conserved in a chemical reaction. *The quantities of products formed in a reaction are always determined by the limiting reactant. ~All other reactants are in excess (left over)~ *Limiting reactant- the reactant that limits the amount of product formed in a chemical reaction. LIMITING REACTANT FLASH CARD *It is a limiting reactant problem when you have two or more givens, tat least 2 are reactants, and you are asked for the quantity of a product. 1) do stoich pattern for all given reactants. 2) reactant that makes the least amount of product = limiting reactant *least amount of product made = expected yield or theoretical yield. *all other reactants = in excess --> only accept lowest answer, cross out all others. 3) once you determine the limiting reactant, all other problems start with it. In other words the limiting reactant determines all other quantities, both those made or used. FINDING AMOUNT OF EXCESS (FLASH CARD) *to find amount of excess that remains use limiting reactant and change it into amount of excess needed (used) using stoich. pattern. Then subtract that amount from the amount of exccess you started with (given amount). *start - used = left over *Percent yield: (actual yield / expected yield) x 100% (put on flash card) The percent yield of a reaction is the ratio of the actual yield to expected times 100% Expected Yield- the amount of a product that should be produced based on calculations. based on number crunching---stoichiometry. Actual Yield- the amount of a product that is actually obtained from a chemical reaction. **** actual yield and expected yield must match, both units and substance, or they will not cancel out. ---> words that identify the actual yield= produced, yielded, made, collected, recovered, and obtained. *use this for titration math problems. Big M stoich Sandwich 1. Big M known *use Big M to find moles 2. Stoich (must have balanced equation) *moles of given to moles of unknown 3. Big M unknown *use Big M to find volume or Big M