Water And pH

Question 1

Wateris an excellent ____________, which enables it to participate in many chemical reactions.

Answer 1

Nucleophile

Question 2

What is the shape of water molecule?

Answer 2

Tetrahedron

Question 3

Water have 104.5-degree angle that differs from the ideal 109.5 degree angle between hydrogens, why?

Answer 3

As a dipole, water electrical charge is distributed asymmetrically, the strongly electroneg oxygen pulls electrons towards it.

Question 4

Dielectric constant is also called?

Answer 4

Permitivity

Question 5

It is the measure of the ability of a material to resist the formation of an electric field w/in it

Answer 5

Dielectric constant

Question 6

Water have high dielectric constant, what does this do between charged particles?

Answer 6

Decreases the force of attraction

Question 7

A compound with high dielectric constant can easily break ionic bonds, what is the dielectric constant of water?

Answer 7

78.5

Question 8

A nucleophile forms chemical bonds by __________ bonding electrons

Answer 8

Donating

Question 9

Water dissociates into

Answer 9

Hydronium ion (H3O+) and hydroxide ion (OH-)

Question 10

Water is an excellent nucleophile and it is attracted to ________ charges.

Answer 10

Positive

Question 11

What is the ability of water to separate charges between solutions

Answer 11

High dielectric constant

Question 12

The ______ structure of water makes it more capable of forming hydrogen bonds.

Answer 12

Dipole

Question 13

Hydrogen bonds are formed because they are attached to

Answer 13

Electronegative

Question 14

Water can dissolve most organic and inorganic molecules because of this property.

Answer 14

Dipolar structure

Question 15

_______ donates protons or hydrogen bonds.

Answer 15

Acid

Question 16

These are strong bonds that consist of three types; ionic, metallic and covalent

Answer 16

Primary bonds

Question 17

These are weak bonds existing in substances such as water (H-bond and Van der Vaals)

Answer 17

Secondary bonds

Question 18

What happens when you apply electric current to water?

Answer 18

Most of it will dissociate

Question 19

What are hydrophobic bonds?

Answer 19

van der Vaals

Question 20

There is giving of electrons that causes both atoms to be charged

Answer 20

Ionic bonding

Question 21

Electrostatic reactions is also called

Answer 21

Salt bridges

Question 22

Bonds where electrons in the outer shell are shared( swirling) that provide movement of free electrons

Answer 22

Metallic bonds

Question 23

Atoms binded with this bond have good thermal and electrical conduction.

Answer 23

Metallic bond

Question 24

A bond between an electronegative atom with a hydrogen covalently bonded to another electronegative atom

Answer 24

H-bond

Question 25

H-bond is weaker than covLent bond because

Answer 25

No electrons are shared

Question 26

What force is produced from a H atom bonded to N,O or F

Answer 26

Dipole-dipole force

Question 27

What is the bond that is formed in secondary structure of proteins?

Answer 27

H-bond

Question 28

What is the bond responsible for alcohol-water, and alc-alc interaction?

Answer 28

H-bond

Question 29

Highly repulsive forces that repel water, making it hydrophobic

Answer 29

Van der Vaals

Question 30

Bonds that stabilizes globular proteins when neutral R-groups reassociate with one another.

Answer 30

Van der Vaals

Question 31

Forces that holds water in liquid state until boiling

Answer 31

Van der Vaals

Question 32

Electrostatic interactions or salt bridges are seen what structure of protein?

Answer 32

Tertiary structure

Question 33

The nucleophilic attacks of water result in the cleavage or breakage of bonds of amide, glycoside or ester bonds

Answer 33

Hydrolysis

Question 34

What will aid the breakage of sucrose to glucose and fructose?

Answer 34

Water

Question 35

These acids like HCl and H2SO4 completely dissociate in strongly acidic solutions

Answer 35

Strong acids

Question 36

What is the protonated form of an acid?

Answer 36

HA or RNH3+

Question 37

This is the measure of relative strength of acids and bases

Answer 37

Dissociation constant (Ka)

Question 38

____ is the negative logarithm of Ka

Answer 38

pKa

Question 39

The lower the pKa, the __________ the dissociation constant

Answer 39

Higher

Question 40

The higher the dissociation constant, the -______ the acid because it has a greater tendency to dissociate

Answer 40

Stronger

Question 41

These are acids with more than one dissociable groups ( like carboxyl and amino group)

Answer 41

Diprotic acid

Question 42

The dissociation of H in diprotic acids is influences by changes in

Answer 42

pH

Question 43

What is the formula of acid dissociation constant?

Answer 43

Ka=[H+]+[A-]/[HA]

Question 44

What is the dissociation constant of water?

Answer 44

10^14

Question 45

At lower temperature, Kw ________.

Answer 45

Decreases

Question 46

What is the pH of a soln whose H ion conc is [0.0001]?

Answer 46

4

Question 47

What is the ph of a soln whose hydroxide ion conc is 4.0x10^-4 mol/L?

Answer 47

``` pOH= 3.4 pH = 10.6 ```

Question 48

Ph is equal to pKa + log [A-/HA], what is the ph when A- and HA are equal?

Answer 48

pH = pKa If 10/1, pH = pKa +1

Question 49

What is the tendency of a soln to resist change in pH ff addition of strong acid or base to prevent abrupt changes?

Answer 49

Buffering

Question 50

What is the maximum buffering region?

Answer 50

Plus 1 and minus 1 pH levels

Question 51

What are the 3 important buffer systems?

Answer 51

1. Bicarbonate 2. Inorganic orthophosphates 3. Intracellular proteins such as hemoglobin

Question 52

CO2 in the body produces H+, if there is an increase in CO2 in the body, it becomes _________.

Answer 52

Acidic

Question 53

What are the two organs that play a role in maintaining pH?

Answer 53

Kidneys and lungs