Chem 106 – Chemistry – Flashcards

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product favored
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once reaction has reached equalibrium, the greater concentration is on the product side
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reactant favored
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once the reaction has reached equalibrium the concentration is on the reaction side
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equalibirum constant (K)
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  • changes with temperiture
  • changes when stoichiometric coefficients change
  • changes when reaction is reversed
  • Remains the same when different concentrations are used.
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ICE table
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used to determine concentrations
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equalibrium consintration expression
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  • all concentrations are at equlibrium values
  • product concentrations appear in the numerator, and the reactant concentrations appear in the denominator
  • each concentration is reised to the power of it's stoichiometric coefficient in the balanced chemical equation;
  • the value of the contant K depends on the particular reaction and the temperature
  • units are never given with K
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;never included in equilibirum expression?
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  • solid reactants and products;
  • molar concentration of water;
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K;1

Ka/b;1

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Product favored at equalibirum.

strong acid/bases

;

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completion in regards to a reaction
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essentially all have been converted to water it was sapouse to.;
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K;1
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reaction is reactant- favored at equilibrium
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reaction quotiant q
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at an point as the reaction proceeds from the reactants to an equailibrium mixtrue.;
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Q;K
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reactants must be converted to products for equilibruim
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Q;K
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some products must be converted to reactants for equilibrium
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short cut to solving equalibrium concentration equation
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if 100 * K ; 2 order of magnetude than initial product [A], then the denominator x can be removed.

;

k = [B][C]/[A]

K = xx/A-x;

K= xx/A

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what is the equilibrium constant for the new K when there are new stoichiometirc ratio's?
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it is the old K raised to the power of the miltiplication factor of the stoichiometric number
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what happens to K when the chemical equation is revervsed?
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the new K is the reciprocal of the old K
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how is the new K found when adding two reactions together?
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The two K's are multiplied to find the new K
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how is the equalibrium constant disturbed?
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  • temperature
  • change in concentration
  • change in volume
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Le Chateleir's principle
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how reaction will adjust to the quantities of reactants and products so that equilibtium is restored
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what side will equilibrim favor of a gass reaction when volume is increased?
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the side with more molecules 
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what side will an equilibrium favor of a gass reaction when volem is decreesed?
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the side with the smallest number of gass molecules
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what happens to the energy flow when the reaction is heated
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the energy is obsorbed meaning it is endothermic
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Arrhenius definition of an acid and base
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any substance that when dissolved in water increases the concentration of H+ ions is an acid. any substance that increases the concentration of hydroxid ion is a base
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Bronsted - Lowery definition of acid and base
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acid is a proton donar and a base is a proton acceptor
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monoprotic acids
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capable of donation one proton 
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polyprotic acids
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capable of donating many protons
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amphiprotic
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ions that can behave either as bronsted acids ro bases 
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all polyatomic ions are ....... when it comes to donating hydtrgen ions
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amphiprotic
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conjugate acide base pair
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consits of two species that differ from each other by the presence of one hydrogen ion
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autoionization 
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water is composed of some H3O and some OH, it is never not conducting electricity
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what is the equalibrium constant for water at 25 degrees C
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Kw = [H3O+][OH-] = 1 * 10-14 
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autoionization constant for water
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Kw
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neutral solution
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[H3O+] = [HO-] 

both are equal to 1 * 10-7

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acidic solution
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[H3O+] > [OH-]

 

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basic solution
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[H3O+] < [OH-]
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what is pH
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pH = -log[H3O+]
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what is pOH
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pOH = -log[OH-]
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sum of pH and pOH
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the some of pH and pOH must be equal to 14 at 25 degrees C
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why is the some of pH and pOH always equal to 14?
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Adding acid reaises the concentration of the H3O+ ions so the solution is acidic. to oppose this increase, Le Chatelier's principle predicts that a small fraction of the H3O+ ions will react with OH- ions from whater autoionization to form water, lowering OH until the product of H3O and OH is again eqaul
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how do you define relative strengths of acids?
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measure the oH of soutions of acids of equal concentrations, the lower the pH the greater the concentration of hydronium ions
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what does a large Ka mean?
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  • ionization products strongly favored
  • strongest acids
  • small Kb;
  • all of these aplly to basses
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what happens to the stregnth of Ka;and conjuagate Kb when the molicule has a big organic tail?
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the Ka ( acidity ) decreases

the conjugate Kb increases

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how do polyprotic acids ionize?
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they are broken down into steps
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what happens to the K aspolyprotic acids are ionzed?
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the K ;become smaller
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why does k become smaller as more H+ are being pulled off?
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Because it is getting harder and harder to remove H+ ions. the larger the negative chager ;the more difficult it is to remove H+
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anions that are conjugate bases of strong acids have what kind of effect on the pH
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they are such weak bases that they have no effect on pH solution
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deprotonation
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removal of H+ ions
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how do alkali metal and alaline earth cations effect pH of solution?
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they have no effect
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what are acidic cations limited to?
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metal ations with 2+ or 3+ charges and to ammonium ions
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all metal ions are what in water
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hydrated
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pKa ?
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pKa;= - log (Ka)
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relationship among pK values
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pKa +;pKb;=pKw
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Ka *Kb;= Kw
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the product of Ka for an acie and Kb;for its conjugate base is euql to the constant specifically Kw
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what side does the equalibrium fall on?
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the side with the weeker base or acid
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how do all proton transfer reactions proceed?
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from the stronger acid and base to the weaker acid and base
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what is the net ionic equation for strong base and acid?
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OH + H = H2O
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what are the products of a hydrolsys reaction?
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Kp
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the cantstant for finding the parsail pressures
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Is a conj. acid/base considered to be an acid or a base when looking it up in table 17.4?
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is it is a conj. acid it is considered to be an acid when looking at table 17.4.;
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what happens when equal number of moles of a strong base is mixed with an equal number of a weak acid?
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;The solution is basic with the pH depending on Kb
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mixing strong acid and strong base?
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produces a neutroal solution
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mixing equal number of moles of strong acid with weak base ?
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produces an acidic solution with pH depending on Ka
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what happens when acetic acid (CH3CO2H) a weak acid is mixed with ammonia (NH3)? and why
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The solution is neutraul because the pH depends both of the products formed and both products have a Ka;and a Kb;;That are equal.;

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what happens when mixing weak ka and kb values?
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the pH depends on the relative Ka and Kb values
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how is the pH effected by the inorganic polyptotic acids/bases?
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the pH is many effected by the release of the first H+ ion and not so much by the second
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lewus acid
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is a substance that can accept a pair of electrons from another atom to form a new bond
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lewis base
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is a substance that can donate a pair of electrons to another atom to form a new bond
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acid-base adduct (coordinate covalent bond)
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the product of a lewis acid base reaction
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list some moecules that have both strong acid and strong base
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NaHSO4

KClO4

NaNO3

LiBr

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complex ion
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has a lot of atoms attached to it with a charge;

[Co(H20)4Cl2]+

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when given two Ka's for a reactions how is the equalibrium constant found?
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multiply Ka1 times ka2 
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dynamic equilibrium
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condition in which forward rate of reaction equals reverse rate
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at equilibirum was does the forward and the reverse rate of the reaction equal? what is that called?
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the forward rate equals the reverse rate. that is where we get the equilibrium constant from?
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Typical steps to this cacluation: 

what are the equilbirum concentrations give the about of reactant formed and what is the equilibirum constant?

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1:set up ICE table

2: solve for x

3: caclulate K by the equilbrium constant equation

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What happens to K when T increases?
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The K increases when T increases. When K increases that means that it favors the products.
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what constitutes a strong acid?
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stronger than water
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strong or week acid/ base

 

acetic acid

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CH3co2H

 

weak acid

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what is a buffer?
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buffers always consist of weak acid and conjugate base 

 

or 

 

weak base and conjugate acid

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the comon ion effect
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example of LaChatelier's Principle: a perturbation to a system at equilibirum leads to achisft in the equilibrium that offsets, or minimizes the effect of the perturbation.
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what is the buffer or HF?
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hydrofluoric acid (weak acid HF) and sodium flouride (conj. base F-)
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what is the buffer system for acetic acid?;
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acetic acid (CH3COOH week acid) and sodium acetate ( CH3COO conj. bAse)
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equivalence point of strong acid/ base?
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is always going to be at 7 pH
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the equivalence point of a weak acid with a strong base?
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the ph is controlled by the conjugate base of the acid.;
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weak acid and strong base have the same consentration
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means the pka is = to the ph in a titration
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what is the ph of a weak acid and a strong base at the equivalancy point?
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greater than 7!;
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whem is a substance predicted to be more soluble then ksp value?
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when a salt is the conj. baske of weak acd is there and an
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Kf
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formation constant.;
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will a small or large Ksp precipitate first?
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a small Ksp will presipitate first because it has a larger Kf value.
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how would you calculate the Knet for the disosiation of a solid and an acid?
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you would findthe Ksp and Kform and multiply them
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when are kc and Kp the same?
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when the number of moles of a gaseous reactiant and product are the same

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number of moles = (molicules or prodcuts - products)

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What is the pH have the falloing buffer solutions

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NH4/NH3

CH3CO2H/CH3CO2

HCO3-/CO32-

H3PO4/H2PO4-

answer

9

4.7

10

2

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