chapter 13: Acids and Bases

Question 1

what is an acid

Answer 1

• have a sour taste and ability to dissolve metals

Question 2

what is a base

Answer 2

• bitter taste and feel slippery to the touch

Question 3

what is the Arrhenius theory

Answer 3

• acids increase the concentration of H+ ions in water
• bases increase the concentration of OH- ions in water

Question 4

what is a neutralization reaction and what does it produce

Answer 4

solution of an acid and a solution of a base are mixed

• products of the reaction have none of the characteristic properties of the acidic or basic solution
• produces water and a salt

Question 6

what is a salt

Answer 6

• any ionic compound whose cation comes from a base and anion comes from acid

Question 7

what is the bronsted lowry theory

HA + B —> A + HB

Answer 7

• acids are proton donors (have a removable acidic proton H+)
• bases are proton acceptors ( lone pair of nonbonding electrons)

Question 8

what is an amphoteric substance

Answer 8

a substance that can act as either an acid or base

HCL + H20 –> CL = H3O+

NH3 + H2O –> NH4+ + OH- aq)

* water is acting like a base and an acid*

Question 9

what is a conjugate acid-base pair

Answer 9

acid and a base that differ only in the presence or absence of a proton

• conjugate base: formed by removing a proton from an acid
• conjugate acid: formed by adding a proton to a base

NH3 + H2O = NH4+ OH-

Question 10

what are the 7 strong acids

Answer 10

1. sulfuric acid H2SO4
2. Hydrochloric HCL
3. Hydrobromic HBr
4. Perchloric HCLO4
5. Chloric HCLO3
6. Hydroiodic HI
7. Nitric HNO3

Question 11

what arrow do strong acids and bases use/ strong electrolytes /

what arrow do weak acids and bases/ weak electrolytes use

Answer 11

1. one way arrow not equilibrium bc they dissociate completely
2. weak acids and bases use equilibrium arrows bc they don’t dissociate completely

Question 13

what is a polyprotic acid and monoprotic acid

Answer 13

• monoprotic: 1 ionizable hydrogen
• polyprotic: >1 ionizable hydrogen
• polyprotic is strong and amphoteric conjugate base is weak

Question 14

what group is in organic acids

Answer 14

• carboxyl group and these acids are weak bc H atoms are not ionizable

Question 15

what is Ka used for and what is Ka

Answer 15

Ka is the acid dissociation constant

• used to express the extent to which weak acid ionizes

Question 16

what does a greater Ka mean

Answer 16

stronger the acid

Question 17

how does polarity affect acid strength

Answer 17

• polarity depends on the strength of the H-Y bond
• stability of the H-Y conjug. base
• more polar means more acidic

Question 18

how does bond strength affect acid strength

Answer 18

• very strong bonds are less easily dissociated when weaker ones
• strong bonds = strong acid strength
• weak bonds =weak acid strength

Question 19

what happens to the base when there is a stronger acid

Answer 19

the more stable it is = the less strong

* stronger the acid, the weaker its conjugate base*

Question 20

• how does acidity increase in the periodic table

Answer 20

1. acidity increases from left to right
2. top to bottom down a group

Question 21

what is an oxyacid

Answer 21

OH groups and possible atoms are bound to a central atom

Question 22

what is the rule of oxyacids

Y-O-H

Answer 22

• electronegativity of Y increases, then will the acidity of the substance
• as electron density is drawn toward the Y, the OH bond becomes weaker and more polar
  2. base of the conjug, base is usually an anion

Question 23

what is the rule for oxyacids that have the same number of O atoms

• H-O-I (weakest weak)
• H-O-Br
• H-O- Cl (strong weak)

Answer 23

• acid strength increases w. the increasing EN of the central atom

Question 24

what is the rule for oxyacids that have the same central atom

Answer 24

• acid strengh increases as the number of oxygen atoms attached to the central atom increases

example:

HCLO -weakest

HCLO2 - weak

HClO3 - strong acid

HCLO4 - stronger acid

Question 25

wha tis the most important chemical properties of water related to bronsted and lowry

Answer 25

- autoionization - act as a base or acid - in pure water a few molecules act as bases and a few act as acids

Question 26

what is the Kw expression and what does it equal

Answer 26

Kw = [H3O+][OH] - @ 25 degrees**, Kw for water is 1.0x10^-14** **\* if you measure one of the conc. you can find the other\***

Question 27

what happens if [H3O] increases

Answer 27

OH must decrease, and it is inverse

Question 28

what are neutral solutions

Answer 28

equal amounts of H3O and OH and it equals 1x10^-7

Question 29

what are acidic solutions

Answer 29

larger [H3O] than [OH] [H3O] \>1x10^-7 [OH] \< 1.0x10^07

Question 30

what is a basic solution

Answer 30

larger [OH] than [H3O] [OH] \> 1x10^-7 [H3O] \< 1.0x10^-7

Question 31

what is the ph and what is the neutral number for pH

Answer 31

- the acidity and bascity of a solution is expressed as pH - neutral pH = 7

Question 32

what does a low and high pH range mean and what is the normal range

Answer 32

- low means acidic - high means basic - normal range is 0-14

Question 33

what is the rule of sig figs when using log to calculate pH

Answer 33

of decimal places in the log = the number of sig figs in the OG number

Question 34

what is the formula for pH and H3O

Answer 34

- Ph = -log(H3O) H3O = 10^-pH

Question 35

what is the formula for pOH and OH

Answer 35

pOH = -log[OH] ]OH] = 10^pOH

Question 36

what is the equation for pH and PoH

Answer 36

ph + PoH = pKw = 14.00

Question 37

in an aqeuos solution of strong acids what is the source of H+ ions and how do you calculate the pH

Answer 37

- strong acid is the source and to calculate pH [H3O] = [acid]

Question 38

how to calculate Ka for weak acids

Answer 38

- use an ice table - proton transfers for weak acids are rapid

Question 39

what does percent ionization help us with

Answer 39

show how much of the weak acid has ionized % ion = [H3O]equilibrium \ [HA] initial x 100 = 10-Ph/ Ha initial x 100

Question 40

what happens as the concentration of an acid increases

Answer 40

the strength decreases = pH decreases = % ionization also increases

Question 41

why does % ionization increases as an acid conc. increases

Answer 41

- acid is diuluted by adding water, it shifts the equilibrium to the left ( increase in acid concentration) - to reach new equilibrium the acid needs to ionnize more - shift to the right ( H+ concentration)

Question 42

what are the strong bases

Answer 42

1. LiOH 2. NaOH 3. KOH 4. RbOH 5. CsOH 6. Ca(OH)2 7. Sr(OH)2 8. Ba(OH)2

Question 43

what do most weak bases contain

Answer 43

Nitrogen bc the lone pair makes it a great proton acceptor

Question 44

what is a weak base dissociation constant

Answer 44

Kb B + H2O ---\> Hb + OH

Question 45

what can Kb be used to find

Answer 45

- OH directly and pOH, PH and [H] ## Footnote **- greater value of Kb = stronger base**

Question 46

what is the rule for polyprotic acids

Answer 46

- polyprotic acids ionize in steps H2SO3 is stronger than HSO3 Ka becomes smaller

Question 47

when calculating pH and you're given 2 Ka what Ka should you use

Answer 47

the stronger Ka meaning the one that is the largest

Question 48

when does percent ionizatoin and pH both increase

Answer 48

as the acid becomes more dilute (less concentrated)

Question 49

if you are given a concentration like Ca(OH)2 what happens to the concentration

Answer 49

the concentration doubles because there are two hydroxides

Question 50

what is the factor of Ka value of successive losses of protons

Answer 50

10^3 or greater

Question 51

from polyprotic acids what can you use to determine the pH

Answer 51

- you can use the first dissociation Ka1 to determine the Ka

Question 53

what is the relationship between bond strength and acidity

Answer 53

- weaker bond strength = proton more easily donated= increase in the strength of the acid