Chemistry 131 Test 2 – Flashcards
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| Mole |
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| SI unit for amount of substance |
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| Avogadro's Number |
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| 6.022 x !0^23 |
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| the mole lets us relate |
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| the number of entities to the mass of a sample of those entities |
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| molar mass |
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| the mass per mole of its entities and has units of grams per mole |
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| moles to atoms |
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| multiply by 6.022 x 10^23 atoms/mol |
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| mass % or element X = |
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| ((moles of X in formula x molar mass of X (g/mol))/ (grams of 1 mol of compound)) x100 |
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| mass of an element |
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| mass of compound x ((mass of element in 1 mol of compound) / (mass of 1 mol of compound)) |
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| a mole of substance is |
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| the amount that contains Avogadro's number of chemical entities |
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| empirical formula shows |
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| the lowest whole number of moles, and thus the relative number of atoms |
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| molecular formula shows |
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| the actual number of atoms of each element in a molecule |
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| structural formula shows |
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| the relative placement and connections of atoms in the molecule |
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| combustion analysis is used to measure |
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| the amounts of carbon and hydrogen in a combustible organic compound |
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| isomers |
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| two or more compounds with the same molecular formula but different properties |
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| chemical equation shows |
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| the identities and qualities of substances of substances in a chemical or physical change |
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| theoretical yield |
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| amount of product calculated from the molar ratio in the balanced equation |
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| actual yield |
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| the amount of product actually obtained |
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| theoretical and actual yields are expressed in units of |
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| amount (moles) or mass (grams) |
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| % yield = |
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| (actual yield / theoretical yield) *100 |
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| solute |
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| substance being disolved |
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| solvent |
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| solution dissolving the solute |
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| molarity = |
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| mol solute / L solution |
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| water's great solvent power arises from ______ and ______ which create _________ |
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| the uneven distribution of electron charge and a bent molecular shape which create a polar molecule |
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| covalent bond |
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| electron sharing |
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| ionic bond |
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| electron transfer |
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| what makes a polar molecule |
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| combination of polar bonds and a bent shape |
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| water separates ions by |
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| replacing attractions with others between several water molecules and each ion |
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| solvated |
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| surrounded closely by solvent molecules |
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| soluble ionic compounds are electrolytes |
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| the ions are free to move, and thus, the solution conducts electricity |
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| three types of equations to represent aqueous ionic reactions |
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| molecular equations total ionic equations net ionic equations |
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| molecular equations shows |
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| all the reactants and products as if they were intact undissociated compounds |
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| total ionic equations show |
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| all the soluble ionic substances dissociated into ions |
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| spectator ions |
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| ions that are unchanged on both sides of the equation |
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| net ionic equations shows |
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| only the actual chemical change by eliminating the spectator ions |
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| in a precipitation reaction |
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| 2 soluble ionic compounds react to form an insoluble product |
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| precipitate |
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| insoluble product formed in a precipitation reaction |
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| key event in a precipitation reaction |
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| the formation of an insoluble product through the net removal of ions form solution |
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| metathesis reaction or |
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| double displacement reaction |
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| acid-base reaction or |
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| neutralization reaction |
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| acid-base reaction occurs when |
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| an acid reacts with a base |
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| acid |
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| a substance that produces H+ ions when dissolved in water |
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| base |
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| a substance that produces OH- ions when dissolved in water |
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| acidic solutions arise when |
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| certain covalent H-containing molecules dissociate into ions in water |
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| strong acids and bases |
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| dissociate completely into ion |
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| weak acids and bases |
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| dissociate very little into ions |
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| when no further change in the amounts of reactants and products occur |
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| the reaction has reached a state of equilibrium |
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| salt |
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| ionic compound that results from the reaction of an acid and a base |
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| the acid-base reaction is a |
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| proton transfer process |
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| titration |
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| the known concentration of one solution is used to determine the unknown concentration of another |
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| acid-base indicator |
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| is a substance whose color is different in acid than in base |
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| equivalence point occurs when |
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| the amount (mol) of H+ ions in the original volume of acid has reacted with the same amount (mol) of OH- ions from the buret |
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| end point occurs when |
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| a tiny excess of OH- ions changes the indicator to its basic color (pink) |
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| redox reaction or |
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| oxidation reduction reaction |
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| redox reactions include |
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| the formation of a compound from its ELEMENTS (or the reverse process) |
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| redox reaction is the |
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| net movement of electrons from one reactant to another |
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| oxidation |
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| loss of electrons |
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| reduction |
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| gain of electrons |
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| oxidizing agent |
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| the species doing the oxidizing (causing the electron loss) |
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| reducing agent |
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| the species doing the reducing (causing the electron gain) |
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| the oxidizing agent is |
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| reduced |
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| the reducing agent is |
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| oxidized |
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| H+ is typically the |
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| reducing agent |
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| oxidation number (O.N.) |
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| the charge the atom would have if electrons were transferred completely, not shared |
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| O.N. for group 1A |
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| +1 |
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| O.N. for group 2A |
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| +2 |
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| O.N. for Hydrogen |
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| +1 with nonmetals -1 with metals |
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| O.N. for Oxygen |
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| -1 with peroxides -2 with everything else |
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| O.N. for Fluorine |
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| -1 |
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| O.N. for group 7A |
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| -1 |
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| O.N. for metals in elemental form |
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| 0 |
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| oxidation is shown by |
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| an increase in O.N. |
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| reduction is shown by |
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| a decrease in O.N. |
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| transfer electrons are never free because |
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| the reducing agent loses electrons and the oxidizing agent gains them simultaneously |
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| three types of redox reactions |
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| combination decomposition displacement |
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| combination redox reaction |
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| combining two elements combining compounds and elements |
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| combining two elements |
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| metal and nonmetal form ionic compound two nonmetals form a covalent compound |
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| decomposition redox reaction |
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| a compound forms two or more products, at least one of which is an ELEMENT |
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| types of decomposition redox reactions |
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| thermal decomposition electrolytic decomposition |
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| thermal decomposition |
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| when the energy absorbed is heat |
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| electrolytic decomposition |
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| in the process of electrolysis, a compound absorbs electrical energy and decomposes into its elements |
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| displacement redox reactions |
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| the number of substances on the two sides of the equation remains the same, but atoms (or ions) exchange places |
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| types of displacement redox reactions |
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| double displacement single displacement |
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| double displacement redox reaction |
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| atoms of two compounds exchange places examples- precipitation, acid-base reactions |
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| single displacement redox reaction |
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| one of the substances is an element |
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| combustion |
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| the process of combining with oxygen, most commonly with the release of heat and the production of light, as in a flame |
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| Hydrated Compounds |
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| Compounds in which molecules of water are associated with the ions of the compounds |
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| Law of Conservation of Matter |
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| Matter can not be created nor destroyed |
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| Coefficients |
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| Indicates the number of moles involved in the reaction. |
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| Stoichiometric Factor |
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| Also known as the mole ratio. A ratio of the coefficients from two molecules in the balanced equation |
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| Limiting Reactant |
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| The reactant, that limits the amount of product produced. |
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| Measuring Concentrations of Compounds in Solution Equation |
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| M1 x V1 = M2 x V2 |
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| Aqueous Solutions |
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| Solutions in which water is the solvent |
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| types of Aqueous Solutions |
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| Precipitation Acid-Base Oxidation-Reduction |
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| Solubility Rules |
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| All common salts of the Group 1A elements and ammonium are soluble. All common acetates (CH3CO2-), nitrates (NO3-), perchlorates (ClO4-), and chlorates (ClO3-) are soluble. All compounds of Group 7A elements (other than F) with metals are soluble except those of silver (Ag), mercury (Hg) and lead (Pb) All compounds of F with metals are soluble except those of magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and lead (Pb) All sulfates are soluble except those of barium (Ba), strontium (Sr), lead (Pb), calcium (Ca), silver (Ag), and mercury (Hg). Except for those in rule 1, carbonates (CO32-), hydroxides (OH-), oxides phosphates (PO43-), chromates (CrO42-) and sulfides are all insoluble |
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| General properties of acids |
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| Sour taste Act corrosive React with bases to form salt and water |
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| general properties of bases |
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| Bitter taste Feel slippery React with acids to form salt and water |
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| Pressure |
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| The force exerted on an object divided by the area over which it is exerted. |
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| 1 atm = ___ mmHg |
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| 760 mmHg |
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| Boyle’s Law |
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| The Compressibility of Gases (when moles and temp are constant) |
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| Boyle’s Law Equation |
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| P1V1= P2V2 |
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| Charles Law |
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| if a given quantity of gas is held at a constant pressure, its volume is directly proportional to the Kelvin temperature |
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| Charles' Law Equation |
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| V1/T1 = V2/T2 |
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| According to Boyle's Law, the volume of an amount of gas is |
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| inversely proportional to the pressure |
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| According to Charles' Law, the volume of an amount of gas is |
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| directly proportional to the Kelvin temperature at a costant pressure. |
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| General or Combined Gas Law Equation |
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| P1V1/T1 = P2V2/T2 |
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| Avogadro’s Hypothesis |
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| the volume of a gas at a given temperature and pressure is directly proportional to the amount of gas in moles. |
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| Ideal Gas Law Equation |
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| PV=nRT |
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| R is |
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| gas constant |
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| R = |
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| 0.08201 L*atm/K*mol |
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| The Density of Gases |
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| The amount (n,mols) of any compound is given by its mass (m) divided by its molar mass (M). |
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| Density of a gas equation |
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| d=m/v=PM/RT |
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| n is |
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| the number of moles |
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| n = |
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| m/M |
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| Partial Pressure |
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| the pressure of each gas in the mixture |
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| Dalton’s Law of Partial Pressure |
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| the pressure of a mixture of ideal gases is the sum of the partial pressures of the different gases in the mixture. |
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| Dalton’s Law of Partial Pressure Equation |
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| Ptotal = P1 + P2 + P3... |
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| Each gas in the mixture acts _______ and can therefore can be considered to behave as an ______. |
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| independently of all of the others and can therefore be considered to behave as an ideal gas. |
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| X1 is |
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| the mole fraction |
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| P1 = |
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| (X1)(Ptotal) |
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| The molecules in a gas sample do not ________ |
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| all move at the same speed. |
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| All gases, regardless of their molecular mass, have the same ______ at the same ______. |
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| average kinetic energy at the same temperature. |
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| The average kinetic energy of gas particles is proportional to ____ |
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| the gas temperature. |
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| Diffusion |
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| the mixing of two or more gases due to their random molecular motions |
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| Effusion |
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| the movement of a gas through a tiny opening in a container into another container where the pressure is very low. |
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| Graham’s Law |
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| The rate of effusion of a gas is inversely proportional to the square root of the mass of its particles. |
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| _______ molecules with _______ average speeds strike the barrier more often and pass more often through it |
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| Lighter; higher |
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| Van der Waals Equation |
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| developed to take into account the cases in which the ideal gas equation breaks down. |
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| Diffusion |
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| the mixing of two or more gases due to their random molecular motions |
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| gas volume changes significantly with |
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| pressure and temperature |
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| increasing the force on the piston ____ the gas volume |
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| decreases |
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| gas flows very |
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| freely |
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| gases have ____ densities |
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| low |
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| pressure is |
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| the force exerted per unit of surface area |
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| pressure = |
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| force / area |
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| barometer |
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| used to measure atmospheric pressure |
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| 1 atm = ___ mmHg |
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| 760 mmHg |
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| 1 torr = ____ mmHg |
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| 1 mmHg |
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| Si unit of pressure |
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| Pascal (Pa) |
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| ideal gas |
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| one that exhibits linear relationships among volume, pressure, temperature and amount of gas |
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| STP |
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| 0*C (273.15 K) and 1 atm (760 torr/ mmHg) |
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| standard molar volume |
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| 22.4 L |
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| PV= |
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| nRT |
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| r = |
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| 0.0821 L*atm/ K*mol |
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| V = |
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| nRT/ P |
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| n = |
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| m/M or PV/RT |
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| density = |
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| MP/RT or m/V |
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| M = |
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| mRT/PV |
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| Ptotal = |
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| P1 + P2 + P3 .... |
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| P1 = |
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| X1 x Ptotal X1 = mole fraction (n1/ntotal) |
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| Postulates of Kinetic Molecular Theory |
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| Postulate 1: Particle volume - assumed to be zero Postulate 2: Particle motion - constant random straight line Postulate 3: Particle collision - elastic |
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| temperature is a measure of |
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| the average kinetic energy of a particle |
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| Graham's Law of Effusion |
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| the rate of effusion of a gas is inversely proportional to the square root of its molar mass |
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| Diffusion |
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| the movement of one gas through another |
