chapter 14: acid base eqilibrium Flashcards by Kisana Ngwenya

what are water-soluble ionic compounds

salts

How well did you know this?

Not at all

Perfectly

nearly all salts are what

strong electrolytes

How well did you know this?

Not at all

Perfectly

what is hydrolysis

when ions are able to react w/ water to generate H+ or OH- ions

How well did you know this?

Not at all

Perfectly

how can the pH of an aqueous salt solution can be predicted

qualitatively by considering the ions of which the salt compos

How well did you know this?

Not at all

Perfectly

what is an anion, X^-

conjugate base of an acid

How well did you know this?

Not at all

Perfectly

what will a strong acid or base do to the pH

they will have no effect on the pH ( and make sure to cancel them out

How well did you know this?

Not at all

Perfectly

if you have a weak acid then what is the strength of its conjugate base

the base is also weak

How well did you know this?

Not at all

Perfectly

to what extent will acetate ion react with water and what does it do to the pH

react to a small extent
- increases the pH and makes it basic

How well did you know this?

Not at all

Perfectly

anions w/ ionizable protons are what

amphoteric

How well did you know this?

Not at all

Perfectly

the behavior w/ water is determined by what

the magnitude of Ka or Kb

How well did you know this?

Not at all

Perfectly

if Ka > Kb

ion will cause the solution to be acidic

How well did you know this?

Not at all

Perfectly

if Kb> Ka

the solution will be basic

How well did you know this?

Not at all

Perfectly

polyatomic cations that contain one or more protons can be considered what

conjugate acids of weak bases

How well did you know this?

Not at all

Perfectly

what can metal ions react with that will affect the pH

react with water to decrease the pH of an aqueous solution

How well did you know this?

Not at all

Perfectly

what other ions do not affect pH

ions of alkali metals
heavier alkaline earth metals

How well did you know this?

Not at all

Perfectly

what can cause a shift of the electron density in water

attraction between nonbonding electrons on O2 and and the metal

How well did you know this?

Not at all

Perfectly

greater charge =

smaller size = more acidic

How well did you know this?

Not at all

Perfectly

strong electron interaction characteristics

greater charge and smaller size

How well did you know this?

Not at all

Perfectly

weak electrostatic interactions

smaller charge = larger size

How well did you know this?

Not at all

Perfectly

cation is from a strong base; anion is from a strong acid

pH is neutral

How well did you know this?

Not at all

Perfectly

cation is from a strong base; anion is from weak acid

(NaC2H3O2)

basic soln

How well did you know this?

Not at all

Perfectly

cation is a conjugate acid of weak base; anion is from strong acid
NH4CL

acidic

How well did you know this?

Not at all

Perfectly

what is the formula for a solution

cation + anion

How well did you know this?

Not at all

Perfectly

cation is highly charged metal ion; anion is from strong acid
Al(NO3)

acidic

How well did you know this?

Not at all

Perfectly

what happens when NaC2H3O2 is added to a solution

- NaC2H3O2 dissociates completely - increase in C2H3 O2 ions

what does an increase in C2H3O2 ions cause HC2H3O2---\> H+ + C2H3 O2

- equilibrium will shift to the left - makes more acid

what is the common ion effect

extent of the ionization of a weak electro. is decreased by adding a strong electrolyte that has an ion in common

if you have a concentratoin of a strong acid then what is that concentration also equal to

- H3O + concentration - use this conc. to calculate pH directly

what is a buffer solution

weak conjug. acid/base pair that resist drastic changes in ph

what can a buffer neutralization not do

consume one another that is why we use weak acids and bases

what pH can you buffer a solution

- at any pH

what are the 3 ways to make an effective buffer

- weak acid and salt contains conjugate weak base - weak base and salt that contains conjugate weak acid - two salts that contain different anions that correspond to the same polyprotic acid NaHCo3 and Na2CO3 HCo3 = was and CO3 is wb

what is the henderson hassbelbalch equation and what is is used for

pH = pKa + log (base/acid) - calculates pH of a buffer from Ka and initial concs of the weak acid and salt of the conjug base

what happens when a strong acid is added to a buffer

the H+ is consumed by X- to produce HX

what happens when a strong base is added to a buffer

OH is consumed by HX to produce X

what is buffer capacity

the amount of acid to base the buffer can neutralize before the pH begins to change

what does buffer capacity depend on

the amount of acid and base from which the buffer is made

if you have large amounts of conjugate acid-base pair what happens

the more resistant the pH is to change

what is the pH range

range over which the buffer acts effectively

when do buffers most effectively resist change

when the conc. of the weak acid and conjug. base are about the same - pH = pKa

when ph= pka what does it mean

- optimal pH of any biffer

what is a titration

analytical technique to calculate the conc. of a solute in a solution

what is the standard solution

solution of a known concentration

what is the equivalence point

point at which the two different solutions (known + unknown) are at stoichiometrically equivalent quantitties

what are indicators

dyes that show a color change right past the equivalence point

is the equivalence point found? if not what is found

no, the endpoint is found

what are most indicators

weak acids

what can be used to monitor the progression of a titration curve

a pH meter

what are some characteristics of a strong acid-base titration 1. how to measure pH before the addition of the base?

1. before base: pH can be calculated from the conc. of the strong acid (-log) 2. initial acid conc. starts closer to 1 and is very low and base pH is high 3. base is added pH increases and is rapid near the equivalence point

what is the equivalence point and what is the pH

moles of acid = moles of base - the pH = 7.00

in a strong acid-base titration what happens as more base is added, how do you find the pH

- the pH levels off and pH is determined by the conc. of the excess base

what is the end point

the point where the indicator changes color( approx. the equivalence point)

what are some characteristics of a weak acid-strong base titration

- initial acid starts at a higher pH - base is at a high pH

in a WA-SB titration how do you determine the pH

the pH is determined by the acid but since it is a weak acid we need to know the Ka

what happens prior to the equivalence point of a WA-SB titration and what happens after

1. weak acid is neutralized to the weak base and the solution contains a **mixture** of the WA and CB 2. after we are left with the conjugate of the WA

what happens at the equivalence point of WA-SB

moles acid = moles of base - base reacts with acid to form a salt pH \>7 because Na+ doesn't have an effect on pH

what are some titration curve comparisons

1. weak acid solns have a higher initial pH than strong acid of the same conc. 2. pH change at the rapid rise near the equiv. point is smaller for a weak acid 3. pH @ Equiv is \>7 for weak acids and 7 for strong acids

why is Ka an important factor in weak acid titrations

- strength of weak acids has an effect on pH curve - weaker the acid = greater pH value @ equivalence point= shorter vertical region

what are some characteristics of a strong acid-weak base titration

1. goes in the other direction 2. the initial acid pH is low and base is not that high 3. pH @ equivalence is less than 7.00

chapter 14: acid base eqilibrium Flashcards

(60 cards)