8 Acids and bases

Question 1

What are the main features of acids and bases?

(What makes the acid sour,… )

Answer 1

X

Question 2

What is a conjugate acid?

Answer 2

X

Question 3

What is a monoprotic acid?

Answer 3

Monoprotic acid:

A monoprotic acid is an acid that donates only one proton or hydrogen atom per molecule to an aqueous solution.

Question 4

Define a Lewis acid and base.

Answer 4

Lewis acid:

Lewis acid is “an electron pair acceptor”

Lewis base:

Lewis base is “an electron pair donor”.

Question 5

Descirbe a typical example of forming coordinate bonds.

(boron trifluoride and ammonia)

Answer 5

Ammonia donates a lone pair of electrons to form a coordinate bond. Boron, 1s2 2s2 2p1, forms three sp2 hybrid orbitals, resulting in a vacant unhybridized 2pz orbital (figure 1). The lone pair on the nitrogen atom forms a coordinate bond with the empty 2pz orbital of the boron atom.

Question 7

Define key features of weak and strong acids.

Answer 7

Weak acids:

A weak acid is one that doesnt dissociate in water.

Strong acid:

A strong acid is one that does dissociate in water.

Question 9

What do all amines have in common?

Answer 9

All amines are weak bases.

Question 10

What do weak acids and bases have in common?

Answer 10

Both weak acids and bases only partially dissociate in water.

Question 11

What is a acid deposititon?

Answer 11

A complex chemical and atmospheric phenomenon that occurs when emissions of sulfur and nitrogen compounds and other substances are transformed by chemical processes in the atmosphere and then deposited on earth in either wet or dry form.

Question 12

At what pH is rain considered to be acid deposition?

Answer 12

At anything less then a pH of 5.0

Question 13

Identify 2 sources of acid deposition.

Answer 13

Sulfur dioxide:

Nitrogen:

Question 14

Outline key methods for reducing productionn of these oxides.

Answer 14

X

Question 15

Name and describe the negative consequences of acid deposition.

Answer 15

Damage to buildings:

Attacks common materials used in buildings (marble, limestone)

ECO systems:

It changes the pH from optimum level to dangerous for trees and animals.

Question 16

Outline key methods for reducing production of acid deposition.

Answer 16

Pre combusition methods:

reduce sulfur emissions refer to techniques used on fuels before their combustion. Physical cleaning or mineral beneficiation involves crushing coal,

Post combustion methods:

focus on several complementary technologies to remove sulfur dioxide, nitrogen oxides, heavy metals and dioxins from the combustion gases before they are released into the atmosphere.

Question 17

Outline a few methods of preventing damage of preventing damage by acid deposition.

Question 18

Describe the Acid deposition of nitrogen.

Answer 18

Question 19

Describe the acid deposition of sulfur dioxide.

Answer 19

Question 20

Size of K_a,K_b,pK_a,pK_b​ values

What does a large K_a indicate and

what does a large pK_a indicate

Answer 20

A large K_a indicates a strong acid because it means the acid is largely dissociated into ions.

The pK_a gives the same information, just in a opposite way. SO if the pK_a is large it means it is a weak acid.

pK_a values for weak acids are between 2-14.

Question 21

What happens when a Strong acid and a weak acid react.

(will the product be completely neutralized)

Answer 21

No it wont be fully neutralized.

Question 22

What wil a weak acid reacting with a strong base form.

What wil a strong acid reacting with weak base form.

Answer 22

The product (salt) of a weak acid will make the solution slightly alkaline.

The product (salt) of a weak base will make the solution slightly acidic.