Chapter 17

Question 1

What is the common ion effect?

Answer 1

Whenever we have a weak acid and then add a strong electrolyte that produces the conjugate base of that acid, the weak acid’s equilibrium is driven to the left .
i.e if your given a reaction: CH3Cooh + H2OCH3OO- + H3O+
- what would happen if you added: CH3COONa–> CH3COO- + Na+.
shift left.

Question 2

What is a buffered solution?

Answer 2

Solutions that contain a weak acid and its conjugate base (like the examples mentioned in common ion effect) resist drastic pH changes when small amounts of strong acid or strong base are added to the.

Question 3

What are the two methods to calculating the pH of a buffered solution?

Answer 3

• Common ion affect approach.

- The Henderson Hasselbauch equaiton.

Question 4

What is a buffer capacity?

Answer 4

• The amount of acid and base that the buffer can neutralize, prior to the pH starting to change hella.

Question 5

What is the equivalence point?

Answer 5

The points where the amount of acid and base and equal.

- Have neutralized one anther.

Question 6

What does the titration curve of a strong acid - strong base titration look like?

Answer 6

• Begins with a low pH, and it slows begins to rise and extended in the lateral direction, this indicates that strong acid is getting used up as the base is being added.
• Then the graph will begin to climb rapidly in pH with small amounts of base added, this is because the proportions of acid to base are near.
• ones mols of acid and base are equal: (equivalence point is found in the middle of the vertical line)
  -Finally the graph will project laterally with slight changes in pH in basic region of numbers, x>7.
  -

Question 7

What does the titration curve of strong base - strong acid look like?

Answer 7

• Begins with a high pH, and it slows begins to fall and extended in the lateral direction, this indicates that strong base is getting used up as the strong acid is being added.
• Then the graph will begin to drop rapidly in pH with small amounts of acid added, this is because the proportions of base to acid are near.
• the moles of acid and base are equal: (equivalence point is found in the middle of the vertical line)
• Finally the graph will project laterally with slight changes in pH in acidic region of numbers, x<7.

Question 8

What does the titration curve of weak Acid - Strong Acid look like?

Answer 8

• Begins with a lowish pH (higher than a strong acid), and it slows begins to rise and extended in the lateral direction, this indicates that strong acid is getting used up as the base is being added.
• Prior to reaching the vertical line, the lateral portion leading up to it has a point of inflection (frowned face)
• Then the graph will begin to climb rapidly in pH with small amounts of base added, this is because the proportions of acid to base are near.
• ones mols of acid and base are equal: (equivalence point is found in the middle of the vertical line)
• Finally the graph will project laterally with slight changes in pH in basic region of numbers, x>7.

Question 9

In a strong acid strong base titration how do you calculate the initial pH?

Answer 9

• since no base has been added yet you do the following:
• Find the pH of the initial concentration of the acid.
• -log({acid})

Question 10

How do you find the pH of a point between the initial and and the equivalence point?
- Strong acid Strong base titration.
-

Answer 10

• since we are adding base to neutralize the acid, but we have yet to reach the equivalence point we know there is still more acid to be neutralized.
• ## The left over acid (waiting to be neutralized acid is) is what we will use to calculate the pH.

Question 11

How do you find the pH of the equivalence point?

- Strong acid Strong base titration.

Answer 11

• ## it is seven since the moles of acid and base are equivalent, thus yielding a neutral pH.

Question 12

How do you find the pH of a point between the final and and the equivalence point?
- Strong acid Strong base titration.

Answer 12

• The pH of the solution after the equivalence point is calculated from the excess OH- in solution.

Question 13

What is a buffer?

Answer 13

weak acid and its conjugate base
or
weak base and its conjugate acid
or
strong acid and weak base, but there must be more weak base.
or
strong base and weak acid, but there must be more weak acid then base
—————————————————–
- tips in problems make sure it isn’t a strong acid
- look for the donation of a hydrogen

Question 14

What is an Ideal buffer?

Answer 14

• The concentration of the weak acid is = concentration of the weak base.
• at the equivalence point.

Question 15

What is true is your making a buffer via mixing a strong acid and a weak base?

Answer 15

• There needs to be a higher amount of weak base.

Question 16

What is true is your making a buffer via mixing a strong base and a weak acid?

Answer 16

• the weak species must be in a greater amount than the strong.