Acids & Bases

Question 1

What is the arrhenius definition of an acid?

Answer 1

susbtances the produce H+, or H3O+ in aqueous solution

Question 2

What is the arrhenius definition of a base?

Answer 2

substances that produce OH- in aqueous solution

Question 3

What is the Bronsted-Lowry definition of an acid?

Answer 3

a proton (H+) donor

Question 4

What is the bronsted-lowry definition of a base?

Answer 4

a proton (H+) acceptor

Question 5

What are amphoteric substances? Examples?

Answer 5

substances that can act as either an acid or a base

H2O, H2PO4-, bicarbonate, amino acids

Question 6

What is a conjugate acid-base pair? Examples?

Answer 6

consists of two substances that differ only by the presence of a proton

H2O is conjugate acid of OH-, OH- is conjugate base of H2O

Question 7

What is the conjugate base of HCO3- if it reacts with water? What about the conjugate acid?

Answer 7

CO3-

H2CO3

Question 8

What is the general equation for an acid reacting in water?

Answer 8

HA + H2O –> H3O+ + A-

Question 9

If you put one mole of a strong acid into water what are the expected products?

Answer 9

would completely ionize (dissociate) and you would get one mole of H3O+ and one mole of the corresponding anion

Question 10

What are some examples of strong acids?

Answer 10

hydrochloric acid (HCl), hydrobromic acid (HBr), Hydroiodic acid (HI), Nitric acid (HNO3), Perchloric acid (HClO4), Sulfuric acid (H2SO4)

Question 11

If you put one mole of a weak acid into water what do you think will happen?

Answer 11

only partially ionize, amount that will ionize is reflected by the Ka value

Question 12

What is the formula for Ka? What is ingored in this formula, why is it ignored?

Answer 12

Ka=[A-][H3O+]/[HA]

water, because its a solvent with a constant concentration

Question 13

How can you tell which weak acid is stronger?

Answer 13

higher Ka means stronger and lower pka means stronger

Question 14

What is the general equation for a base reacting in water?

Answer 14

NaOH + H2O –> Na+ + OH-

Question 15

What are some strong bases?

Answer 15

sodium hydroxide (NaOH), lithium hydroxide (LiOH), potassium hydroxide (KOH), strontium hydroxide (Sr(OH)2), calcium hydroxide (Ca(OH)2), barium hydroxide (Ba(OH)2)

Question 16

What is the formula for Kb? What is ignored and why?

Answer 16

Kb=[BH+][OH-]/[B]

water, because its a pure solvent

Question 17

How can you tell which weak base is stronger?

Answer 17

bigger Kb, means stronger as well as smaller pKb

Question 18

What is the autoionization of water?

Answer 18

when water acts as an acid and a base by transfering a proton to another water

Question 19

What is the the Kw constant?

Answer 19

Kw=[H3O+][OH-]=1.0x10^-14

Question 20

How can you calculate the concentration of OH- using H3O+ concentration and Kw?

Answer 20

[OH-]=Kw/[H3O+]

Question 21

How can you calculate pH?

Answer 21

pH=-log[H3O+]

Question 22

What pH is basic, acidic, or neutral?

Answer 22

basic is greater than 7, acidic is less than 7, neutral is 7

Question 23

How can you calculate pOH?

Answer 23

pOH=-log[OH-]

Question 24

What equation can you use to find pH if you know pOH and vice versa?

Answer 24

pOH + pH = 14

Question 25

How can you calculate [H+] if you know pH?

Answer 25

10^-pH

Question 26

How can you calculate pKa and pKb?

Answer 26

pKa=-log(Ka) pKb=-log(Kb)

Question 27

How can you find the pKa of a conjugate base pair if you know pKb and vice versa?

Answer 27

pKa + pKb = 14 only for conjugate acid-base pairs in water

Question 28

How can you calculate Ka or Kb if you know the other of a conjugate acid-base pair?

Answer 28

Kb x Ka = Kw

Question 29

How can you find pH of a weak acid/base?

Answer 29

ICE tables

Question 30

What is the formula for % ionization of a weak acid?

Answer 30

=[H3O+]/(initial acid concentration) x 100

Question 31

WHat is a general formula to find % ionization?

Answer 31

= square root (Ka/Ca) x 100

Question 32

If there is a mixture of acids, when can we find the pH?

Answer 32

if one acid is much stronger than the others, can ignore the other acids

Question 33

What is the properties of ions and salts for anions?

Answer 33

anions that are the conjugate base of a weak acid is itself a weak base, and anions that are the conjugate base of a strong acid is pH-neutral

Question 34

What is the properties of ions and salts for cations?

Answer 34

A cation that is the conjugate acid of a weak base is itself a weak acid, a cation that is the conjugate acid of a strong base is pH-neutral

Question 35

What are polyprotic acids?

Answer 35

can donate more than one proton

Question 36

If the Ka of the 1st proton for a polyprotic acid higher than the subsequent ones, why?

Answer 36

yes the removal of a second and third H+ involves a separation of a positive charge (H+) from a negatively charged anion, which are attracted by coulombic forces.

Question 37

How can you find the volume of a certain acid/base to make a solution with a certain pH and volume?

Answer 37

Find concentration of H+ or OH- (10^-pH or 10^-pOH) Multiply that by the volume Divide that by the concentration of the acid/base