Chapter 20 - Acids, Bases, and pH

Question 1

What is a Bronsted-Lowry acid defined as?

Answer 1

A proton (H+) donor

Question 2

What is a Bronsted-Lowry base defined as?

Answer 2

A proton (H+) acceptor

Question 3

What is a conjugate acid-base pair?

Answer 3

a conjugate acid-base pair is Two species that can be interconverted by transfer of a proton.

e.g hcl+ h2o = h30+ + cl-
hcl and cl- are conjugate base pairs
h3o+ and h20 and conjugate base pairs

Question 4

In the dissociation of HCl to H+ and Cl-, identify the conjugate acid and base.

Answer 4

HCl releases a proton so is therefore the conjugate acid.

Cl- accepts a proton so is therefore the conjugate base.

Question 5

When water is the base, what is formed?

Answer 5

H(3)O+

Hydronium ion

Question 6

What do the terms monobasic, dibasic and tribasic refer to?

Answer 6

The total number of hydrogen ions in the acid that can be replaced per molecule in an acid-base reaction.

monobasic has one hydrogen
dibasic has two hydrogens
tribasic has three hydrogens :)

Question 7

How can redox reactions be simplified?

Answer 7

Remove the spectator ions

Question 8

What is the word equation for the reaction of an acid and a metal? what’s the acronym to remember it?

Answer 8

acid + metal -> salt + hydrogen

MASH
metal acid = salt + hydrogen

Question 9

What is the word equation for the reaction of an acid and a carbonate? whats te acronym?

Answer 9

acid + carbonate -> salt + water + carbon dioxide

C.A.W.C.S

Question 10

What is the word equation for the reaction of an acid and a base?

Answer 10

acid + base -> salt + water

B.A.W.S

Question 11

What is the word equation for the reaction of an acid and an alkali?

Answer 11

acid + alkali -> salt + water

A.A.W.S

Question 12

What is the relationship between pH and concentration of H+?

Answer 12

Low value [H+] = high pH

High value [H+] = low pH

Question 13

What is the equation for working out pH from [H+]?

Answer 13

pH = -log10[H+]

Question 14

How is the pH calculated for a strong acid?

Answer 14

Assume it fully dissociates

Therefore [H+] [A-]= [HA] before

Question 15

what equation links pKa and Ka?

Answer 15

pKa= -log10 Ka

Question 16

How is the new pH calculated for a strong acid on dilution?

Answer 16

Work out change in concentration of HA and therefore [H+]

Then put back into pH = -log[H+]

Question 17

How is the pH calculated for a weak acid?

Answer 17

Ka = [H+][A-]/[HA]
Ka[HA] = [H+][A-]
[H+] = [A-]
[H+]^2 = Ka[HA]
[H+] = sqrt(Ka[HA]) then sub in :)

Question 18

what the equation for Kw?

Answer 18

Kw= [H+] [OH-]

Question 19

What is Kw?

Answer 19

The ionic product of water. water dissociates slightly acting as a weak acid

H20 = H+ + OH-

1X10^-14

Question 20

What is the value of pKw?

Answer 20

14.00

Question 21

How can pH of strong bases be found when given the concentration of OH-?

Answer 21

pKw (14) = pH + pOH

Question 22

How can pH of weak bases be found when given the concentration of OH-?

Answer 22

pKw = pH +pOH

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

[H+] = [A-]
[A-]^2 = Ka[HA]
[A-] = sqrt(Ka[HA])

Question 23

what does the ph scale look like?

Answer 23

Question 24

what are the two assumptions of weak acids?

Answer 24

[HA] equilibrium = [HA] undissociated

[H+] = [A-]