E-4 Buffers and Titrations Flashcards Preview

Wenger - AP Chemistry > E-4 Buffers and Titrations > Flashcards

Flashcards in E-4 Buffers and Titrations Deck (39):
1

HCl in H2O

not a buffer - this is a strong acid and water

2

NaOH in H2O

not a buffer - this is a strong base and water

3

HCl and NaOH in H2O

not a buffer - this is a strong acid and a strong base - this will neutralize to form NaCl and water

4

HNO2 in H2O

not a buffer - this is a weak acid and water

5

NaNO2 in H2O

Not a buffer - this is a weak base and water

6

HNO2 and NaNO2 in H2O

This is a buffer - nitrous acid is a weak acid and the nitrite ion is its conjugate base

7

HNO2 and NaF in H2O

Not a buffer - nitrous acid is a weak acid but the fluoride ion is not its conjugate base

8

NaHSO4 and H2O

Not a buffer - This is a weak acid and water

9

NaHSO4 and Na2SO4 in H2O

This is a buffer - the bisulfate ion is a weak acid the the sulfate ion is its conjugate base

10

NH3 in H2O

Not a buffer - this is a weak base in water

11

NH4Cl in H2O

Not a buffer - This is a weak acid in water

12

NH3 and NH4Cl in H2O

This is a buffer - ammonia is the weak base and the ammonium ion is its conjugate acid

13

Current pH = 4

  1. A 100 mL sample of buffer made from HNO2/NaNO2 when pKa of HNO2 is 3.40
  2. A 100 mL sample of buffer made from HClO/NaClO when pKa of HClO is 7.5 

Solution 1 - pKa of the acid is closest to the pH of the solution which will make the ratio of weak acid to conjugate base closer to 1:1

14

  1. A 100 mL sample of buffer made from from equal amounts of 1.0 M HNO2 and 1.0 M NaNO2 
  2. A 100 mL sample of buffer made from from equal amounts of 0.10 M HNO2 and 0.10 M NaNO2 

Solution 1 - The higher total concentration has the best buffer capacity

15

  1. A buffer made from from 50mL of 1.0 M HNO2 and 50 mL of  1.0 M NaNO2 
  2. A buffer made from from 20 mL of 0.10 M HNO2 and 80 mL of 1.0 M NaNO2 

Solution 1 - the buffer whose ration of weak acid to base is closer to 1:1 will have the higher buffer capacity

16

Which curve represents a weak acid being titrated with a strong base?

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This one

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17

Which curve represents a strong acid being titrated with a strong base?

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This one

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18

Which curve represents a strong base being titrated with a strong acid?

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This one

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19

Which curve represents a weak base being titrated with a strong acid?

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This one

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20

Which point represents the equivalence point?

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E

21

Which point represents the 1/2 equivalence point?

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C

22

At this point a buffer exists where there is more weak acid than conjugate base.

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23

At this point a buffer exists where there is less weak acid than conjugate base

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24

At this point a buffer exists where the amount of weak acid is the same as the amount of conjugate base

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C

25

At this point a the weak acid has been neutralized and the amount of conjugate base determines the pH.

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E

26

At this point the weak acid has been neutralized and the amount of excess strong base determines the pH?

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F

27

At this (these) point(s) the [H3O+] is greater than the [OH-].

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A, B, C, and D - the pH is less than 7

28

At this (these) point(s) the [H3O+] is less than the [OH-]

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E and F - the pH is greater than 7

29

At this point no strong base has been added and the amount of weak acid determines the pH.

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A

30

Which of the following represents the equivalence point?

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E

31

Which of the following represents the 1/2 equivalence point?

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C

32

The weak base has been nuetralized and the excess strong acid determines the pH.

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F

33

At this point the no strong acid has been added and the amount of weak base determines the pH. 

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A

34

The weak base has been neutralized and the amount of conjugate acid determines the pH.

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E

35

At this point a buffer exists where the concentration of the weak base and the conjugate acid are the same.

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C

36

At this point a buffer exists where the concentration of the weak base is greater than concentration of the conjugate acid.

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B

37

At this point a buffer exists where the concentration of the weak base is less than concentration of the conjugate acid.

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D

38

The [H3O+] > [OH-].

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E and F - the pH is less than 7

39

The [H3O+] -].

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A, B, C, and D - the pH is greater than 7