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33 Cards in this Set
- Front
- Back
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molecule
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2+ atoms held together by covalent bonds
-can be composed of same element or different elements |
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ionic compounds
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3-d array of charged particles
measure in FORMULA WEIGHT do not form true molecules |
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molecular weight(grams)
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measurement of mass
used for compounds other than ionic compounds = sum of atomic weights in a molecule = amu |
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formula weight(grams)
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sum of atomic weights in a molecule
used for ionic compounds |
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avogardos number
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6.02e23
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mol =
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(weight of sample)/molecular mass
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Gram Equivalent Weight
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Molar Mass/n
n = number of ions that can be formed ex) H2SO4 can form 2 H+ H2SO4 --> H+ + HSO4- HSO4- --> H+ + HSO4^2- |
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find the GEW of H2SO4
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H2SO4 = 98g/mol = molar mass
can form 2 ions per molecule so GEW = 98/2 = 49g/ion(H+) |
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Molarity
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Normality/n = mol/L
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monoprotic
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can make 1 H+ ion/mol
ex) HCl |
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diprotic
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can form 2 H+/mol
H2SO4 |
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normality
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measure of concentration
equivalents/L |
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law of constant composition
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all compounds will have same ratio
ex) H2O = 2:1 ratio |
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empirical formula
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most simple ratio
ex) CH2O |
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molecular formula
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normal ratio
C6H12O6 |
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ionic compounds will have ____ formulas
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empirical
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percent composition
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(grams/mol)/formula weight
ex) CH4 = 75% for cabon |
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combination rxn
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A + B --> AB
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decomposition rxn
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AB --> A + B
usually accompanied with heat or electrolysis |
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single replacement
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A + BY --> AY + B
aka redox rxns |
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double replacement
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AB + XY --> AY + BX
aka metathesis can form a precipitant can form weak electrolyte |
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neutralization rxns
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HX + YOH --> H2O + XY
strong acid + strong base --> water and salt |
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net eq
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do not include spectator ions
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spectator ions
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do not react in an eq
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ionic eq
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no compounds within the formula
ex) Zn + Cu2+ SO4^2- --> Cu + Zn2+ + SO4^2- |
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limiting reactant
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limits the amount of product that can be formed
its used up first! |
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what is the limiting reactant in FeS if 28g of Fe and 24g S?
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Fe = 56g/mol
28/56 = .5mol Fe S = 32g/mol 24/32 = .75mol S Fe = limiting reactant |
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determine excess reactant from previous problem
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.75-.5 = .25molS *32 = 8g
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example of limiting reactant when the numbers dont match up as nicely...
39gNa2S 113.3gNaNO3 Na2S + 2 AgNO3 --> Ag2S + 2NaNO3 |
1. Na2S = 23(2) + 32 = 78g/mol
39g/78g = .5mol 2. AgNO3 = 108 + 14 + 16(3) = 170g 113/170 = .66 ratio of Na2S to NaNO3 = 1:2 so modify the numbers... .5mo l * 1 = .5mol Na2S 11.3/17 * 1/2 = .33mol AgNo3 .5 - .33 = .17molNa2S*80 = a little more than 10g |
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% yield
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actual/theoretical
actual < theoretical! |
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actual yield
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amt you are able to actually obtain
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theoretical yield
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amt you could theoretically get
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problem:
percent yield of 27gCu produced; reacted 32,5g Zn with CuSo4 excess Zn + CuSO4 -->Cu + ZnSO4 |
27g = actual
32.5gZn/65g = .5molZn .5molZn * 1molCu/1molZn = .5mol Cu .5molCu* 64g = 32g(theoretical) 27/32 = percent yield = 84% |
