Acids And Bases

Question 1

What are buffers used for

Answer 1

Preventing large pH changes

Question 2

What are good buffers

Answer 2

Solutions of weak acid or base and it’s conjugate

Question 3

Describe the common ion effect

Answer 3

A weak electrolyte will ionize less if you add a strong electrolyte that has an ion in common with the weak electrolyte

Question 4

What happens when you add OH to a solution of HF?

What happens if you add H?

Answer 4

The OH reacts with H to make water. The concentration of H decreases and there will be more F

The H will react with F and produce more HF reducing the F- concentration

Question 5

Which are good buffers?
@-HF and NaF
B-NH3 and NH4Cl
C-KOH and KF
D-CH3COOH and LiCH3COO-
E-NaNO3 and HNO3
F-NaOH and NaCl
G-HCl and Na CH3COO-

Answer 5

A,B,D

Question 6

Within what range do buffers work?

Answer 6

pH=pKa +/-1

Acid base ratio less than 1:10 or 10:1

Question 7

Acid and base amount of optimum buffers?

Answer 7

[HA]=[A]

Question 8

How do make a buffer using table of Ka

Answer 8

Exponent close to pH and equal concentration of acid and base

Question 9

How to find pH of a buffer after adding a substance that changes pH?

Answer 9

Use henderson hasselbach

Question 10

What happens to SA of SB added to a buffer?

Answer 10

All SA or SB are consumed in the reaction

Question 11

Steps for recalculating pH after strong acid or base

Answer 11

Stochiometry
1. Add sB or SA
2. Neutralize
3.. Recalculate [Hx] and [X-]
Equilibrium
Use Kw, [Hx] and [X-] to calculate [H+]
Find pH

Question 12

Alternative hasselbach

Answer 12

Ka=[H3O+] ([A-][HA])

Question 13

How does the PH change when a base is added

Answer 13

Slightly

Question 14

When is pH equal to pKa

Answer 14

When n of acid =moles of base

Question 15

What is the endpoint of a titration

Answer 15

Indicator changes color

Question 16

Equivalence point

Answer 16

n of acid =n of base

Question 17

Titration is correct when

Answer 17

Endpoint and equivalence point reached at the same time

Question 18

Describe the tritration curve of a SA with a SB

Answer 18

Starts low on pH scale.
Slow to reach equivalence point
Equivalence point at 7
Just before and after the equivalence point the pH rapidly increases

Question 19

What is at the equivalence point of a SA+SB

Answer 19

Water + salt of cation of Base and anion of acid

Question 20

Titration of WA+SB

Answer 20

-cB affects pH
pH at equivalence point is>7
-pH changes near equivalence point are more subtle

Question 21

When can you estimate salt solubility from KSP?

Answer 21

When salts have same ion:ion ratio

Question 22

Does solubility change with temperature?

Answer 22

Yes

Question 23

How does the common ion effect change solubility

Answer 23

If there are already ions of the salt in solution the solubility od the salt will decrease

Question 24

In what kind of solution do acids dissolve?

Answer 24

Basic

Question 25

When will a precipitate form?

Answer 25

When a solution bis super saturated Q>Ksp

Question 26

When is a solution unsaturated

Answer 26

Q

Question 27

When is the solubility of a system at equilibrium?

Answer 27

Q=Ksp

Question 28

When do metal ions affect solubility

Answer 28

When they act as lewis acids and react with complex ions that act as lewis bases

Question 29

When metal oxides and hydroxides can act as acids or bases?

Answer 29

When dissolved in strong acid or base

Question 30

Describe gravimetric analysis

Answer 30

Separating a precipitate from a solution by filtration

Question 31

Differences in salts can separate ions in a mixture

Answer 31

True

Question 32

When is a reaction neutralized

Answer 32

When moles of acid =moles of base

Question 33

Volumetric analysis

Answer 33

Find how much substance there is using a titration

Question 34

Titrant

Answer 34

Substance delivered from buret (we know it’s volume)

Question 35

Analyte

Answer 35

Substance that is analyzed (volume must be known)