Question 1 Choose the most likely equivalence point pH for each of...

Question 1

Choose the most likely equivalence point pH for each of the following titrations.

Titration Endpoint

Ammonia titrated with hydrochloric acid 

5

7

9

Lithium hydroxide titrated with hydrobromic acid 

5

7

9

methanoic acid titrated with sodium hydroxide 

5

7

9

Question 2

Match the following terms with the entities. Use each term only once.

EntityClassification

SO3^2−(aq)

Choose...

Polyprotic base

Polyprotic acid

Monoprotic acid

Monoprotic base

HSO3−(aq)

Choose...

Polyprotic base

Polyprotic acid

Monoprotic acid

Monoprotic base

HCOOH(aq)

Choose...

Polyprotic base

Polyprotic acid

Monoprotic acid

Monoprotic base

H2PO4−(aq)

Choose...

Polyprotic base

Polyprotic acid

Monoprotic acid

Monoprotic base

Question 3

Use the following information to answer the next 3 question.

A 10.0 mL sample of phosphoric acid (H₃PO₄(aq)) was titrated with an excess of sodium hydroxide solution.

By examining the formula for phosphoric acid (H₃PO₄(aq)), you might predict that phosphoric acid will have

Select one:

a) 1 equivalence point because it is a weak acid.

b) 2 equivalence points because it is a weak acid.

c) 3 equivalence points because the formula contains 3 hydrogen atoms.

d) 4 equivalence points because the formula contains 4 oxygen atoms.

Question 

Question 4

The reason for the number of observed equivalence point(s) on the above titration curve is

Select one:

a) Each of the flat sections represents an equivalence point; there are three equivalence points because there are three protons that can be donated.

b) There are two equivalence points because all polyprotic acids produce titration curves with two equivalence points.

c) Only the first two reactions are quantitative, the third reaction establishes an equilibrium so it does not show up as an equivalence point on the titration curve.

d) The volume of the sample of the arsenic acid solution was too small; the third equivalence point had not yet been reached

Question 5

Identify the volume of titrant required to reach the second equivalence point.

Second equivalence point occurs at 

 ____mL

Record your 2-digit answer; do not include units.

Question 6

Identify the pH at the first endpoint for this titration curve.

pH at first endpoint 

___

Record your 1-digit answer

Question 7

Identify the pH at the second endpoint for this titration curve.

pH at second endpoint 

___

 

Record your 1-digit answer

Question 8

An indicator that could be used to signify the first endpoint is ...

Choose...

phenolphthalein

bromothymol blue

cresol red

thymolphthalein

chlorophenol red

phenol red

methyl orange

methyl violet

Question 9

An indicator that could be used to identify the second endpoint is... 

Choose...

phenolphthalein

bromothymol blue

cresol red

thymolphthalein

chlorophenol red

phenol red

methyl orange

methyl violet

Question 

10

Use the following information to answer the next 2 questions.

A technician used 0.10 mol/L of HCl(aq) to titrate two separate samples. The first trial involved the titration of 20 mL of a 0.10 mol/L monoprotic weak base. The second trial involved the titration of 20 mL of a 0.10 mol/L monoprotic strong base.

For each of the titrations described above, identify the statement that correctly describes the volume of HCl(aq) required to reach the equivalence point.

Select one:

a) The weak base will require a larger volume of acid as the strong base.

b) The volume of acid required will depend on the exact identity of each base.

c) The weak base will require the same volume of acid as the strong base.

d) The weak base will require a smaller volume of acid as the strong base.

Question 11

Identify the statement that correctly describes the pH of the equivalence point for each of the titrations described above.

Select one:

a) One of the solutions will have a pH higher than 7 while the other will have a pH lower than 7.

b) One of the solutions will be neutral while the other will have a pH lower than 7.

c) One of the solutions will be neutral while the other will have a pH higher than 7.

d_ The pH of both solutions will be neutral.

Question 

Question 12

Equivalence points are represented by ______________

Select one or more:

1

2

3

4

Question 13

Use the following additional information to answer the next question. 

List of species

1. H2SO3(aq)
2. HSO3^−(aq)
3. SO3^2−(aq)
4. OH^−(aq)

From the list of species, select the predominant species present at section 3 of the titration curve.

_____________

Select one or more:

1

2

3

4

Question 

14

The indicator methyl red establishes the following equilibrium

HMr(aq)+H2O(l)→H3O^+(aq )+ Mr^−(aq)

red yellow

NaOH(aq) is added to a slightly red sample of this indicator. To alleviate this stress, the equilibrium will 

Choose...

shift to the left

shift to the right

not shift

and the equilibrium system will 

...Choose...

turn more yellow

turn more red

turn orange

not change in colour

Question 15

Which of the following pairs of compounds could be made into a buffer mixture?

Select one:

H2SO4(aq) and NaHSO4(aq)

H3PO4(aq) and NaOH(aq)

LiHSO3(aq) and Li2SO3(aq)

HCl(aq) and NaCl(aq)

Question 16

Use the following information to answer the next 3 question.

Consider the following buffer equilibrium.

HCOOH(aq)+H2O(l)⇋HCOO^−(aq)+H3O^+(aq)

When a small quantity of NaOH(aq) is added to the above buffer mixture the equilibrium will...

 Choose...

shift to the left

shift to the right

not shift

 and the pH of the equilibrium system will ...

Choose...

increase

decrease

remain constant

 .

Question 17

When a small quantity of HCl(aq) is added to the above buffer mixture the equilibrium will ...

Choose...

shift to the left

shift to the right

not shift

 and the pH of the equilibrium system will ...

Choose...

increase

decrease

remain constant

 .

Question 18

Identify the following statements about buffers as true or false

A buffer mixture will resist changes in pH when a large quantity of either an acid or base is added.

Choose...

true

false

A buffer mixture will resist changes in pH when small quantities of an acid or a base are added, but not both.

Choose...

true

false

A buffer system is composed of a weak acid and its conjugate base.

Choose...

true

false

An ideal buffer mixture should be made with equal amounts of a weak acid and it conjugate base. The weak acid and conjugate base should both be at the same concentration.

Choose...

true

false

Question 19

Use the following information to answer the next question.

Pairs of solutions

1. 1.0 mol/L HNO₃(aq) and 1.0 mol/L LiOH(aq)
2. 1.0 mol/L HBr(aq) and 1.0 mol/L LiBr(aq)
3. 1.0 mol/L HNO₂(aq) and 0.10 mol/L LiNO2(aq)
4. 1.0 mol/L HCO₃^-(aq) and 1.0 mol/L CO₃^2- (aq)

If each of the pairs of solutions listed above is mixed together in equal volumes, then the pair of solutions that could act as a buffer is numbered

Select one:

1

2

3

4

Question 20

Use the following information to answer the next question.

A technician combined 25 mL of 1.0 mol/L HF(aq) with 25 mL of 1.0 mol/L NaF(aq). The following buffer equilibrium was established.

HF(aq)+H2O(l)⇋H3O6+(aq)+F^−(aq)

What would limit the buffering action if a sample of a strong acid was added?

Select one:

a-The amount of hydrofluoric acid present in the system.

b)The amount of water present in the system.

c)The amount of hydronium ion present in the system.

d)The amount of fluoride ion present in the system.

Question