UNIT 3- WATER

Question 1

how many H bonds can water form?

Answer 1

4

Question 2

What is water at room temp and at atmospheric pressure?

Answer 2

liquid state

Question 3

what are the physiochemical properties of water?

Answer 3

1. thermal regulator
2. somotic controller
3. universal solvent

Question 4

what is specific heat capacity?

Answer 4

energy needed to raise the temp by 1 degree

Question 5

what is heat of fusion?

Answer 5

energy needed to convert liquid to ice

Question 6

what is heat of vaporisation?

Answer 6

energy needed to convert gas to vapour

Question 7

as the number of carbon atoms increase in alcohols and amines what happens to the solubility?

Answer 7

it decreases, as chain inc, becomes more nonpolar =hydrophobic and cannot for H bonds

Question 8

as the number of carbon atoms increase in organic solvents what happens to solubility?

Answer 8

it increases

Question 9

why is water more dense as a liquid than in ice ?

Answer 9

molecules are more compact to due cohesive forces

Question 10

how is surface tension formed?

Answer 10

molecules are pulled in at the surface

Question 11

when mols are inward in every direction the net force is what?

Answer 11

net force = zero

Question 12

what is capillarity?

Answer 12

it is ability of a liquid to move thru a narrow space of polar surfaces, against gravity, without external help, in water it is adhesion+cohesion

Question 13

what is solubility?

Answer 13

property of solid, liquid or gas called (solute) to dissolve in solvent = homogenous solution

Question 14

saturated concentration

Answer 14

adding more solute doesn’t inc conc of solution or cause excess solute

Question 15

which molecules dissolve readily in water?

Answer 15

polar mols such as sugars dissolve readily in water as replace solute-solute H bonds w/ energetically favourable water-solute H bonds.

Question 16

polar uncharged mols have a what effect on water?

Answer 16

stabilising effect

Question 17

how does water dissolve salts (ionic sub)?

Answer 17

via hydration (weakening electrostatic interactions)

Question 18

what is the dielectric constant?

Answer 18

water has a big DC, =physical property reflecting, capacity to dissolve ionic substances producing ions

Question 19

keq= eq constant of water ?

Answer 19

1.8 x 10-16 M

Question 20

ionisation of water?

Answer 20

2 H2O-> H3O+ + OH-

Question 21

what is a buffer?

Answer 21

conjugate base ( base with extra H+) + weak acid

Question 22

what is a base? ACC +

Answer 22

GIVES AWAY electrons or OH-

ACCEPTS protons.

Question 23

what is an acid? ACC -

Answer 23

GIVES AWAY protons or H+ ions

ACCEPTS electrons

Question 24

ph?

Answer 24

ph= -log{H+}

Question 25

pOH?

Answer 25

pOH= -log{OH-}

Question 26

kw?

Answer 26

{H+} ={OH-} = 1x10-7M

Question 27

ph scale?

Answer 27

logarithmic scale measures conc H+ and OH-

Question 28

hoe do you measure ph?

Answer 28

• dyes

- ph meter

Question 29

acidosis ?

Answer 29

blood ph lower than 7.35

Question 30

alkalosis?

Answer 30

blood ph above 7.45

Question 31

Arrhenius definition of acid

Answer 31

=substance e- neutral dissociated = H+ + A-

Question 32

Arrhenius definition of base

Answer 32

= substance e- neutral dissociated = OH- + B+

Question 33

Lowry definition of acid

Answer 33

=substance transfers H+

Question 34

Lowry definition of base

Answer 34

= substance captures H+

Question 35

amphoteric ?

Answer 35

acts as base and acid

Question 36

zwitterionic form?

Answer 36

mol/ ion has positive + neg charged groups (functional groups)

Question 37

work out pka?

Answer 37

=-logka

Question 38

pka?

Answer 38

measure of acid strength

Question 39

ka?

Answer 39

measure of weak acid dissociation constant

Question 40

poliprotic acid ?

Answer 40

acid ionize (donates) to more than 1 H+ per mol
di,tri,protic acid H3PO4

Question 41

what does a titration experiment do?

Answer 41

pka acids

Question 42

how to do a titration experiment?

Answer 42

1. acid titrated with strong base

2. acid added in small amounts till neutralised determined with dye or ph meter

Question 43

all weak acids have a buffering zone which is also called?

Answer 43

a flat zone, where pka=ph

Question 44

ka in relation to A.S?

Answer 44

higher ka higher A.S.

Question 45

pka in relation to A.S ?

Answer 45

lower the pka higher the A.S

Question 46

a weak acid + anion (neg charged ion) can act as?

Answer 46

can act as a buffer

Question 47

what is the equivalence point?

Answer 47

enough base is added to react with all weak acid present in sample, ph changes rapidly

Question 48

what does the hederson hassel balch equation show?

Answer 48

describes the shape of titration curve of any weak acid

Question 49

what is the hederson hassel balch equation?

Answer 49

ph= pka + log {A-}/ {HA}

Question 50

what is le chatelieres principle?

Answer 50

if equilibrium becomes unbalanced reaction will shift to restore.

Question 51

what are the 4 buffering systems?

Answer 51

1. buffering solutions (rapid term
2. circulatory system (med term
3. respiratory system (med term
4. renal system (long term

Question 52

which buffering solutions are there? 3

Answer 52

1. proteins
2. phosphate (intracellular) inside cell
3. bicarbonate (blood)

Question 53

the respiratory system buffers what?

Answer 53

partial pressure of co2

Question 54

ph homeostasis is by which proteins?

Answer 54

asp, glu, his

Question 55

renal system buffers what?

Answer 55

kidney adjusts HCO3 in plasma

Question 56

bicarbonate buffering in blood =

Answer 56

carbonic acid as H+ donor and bicarbonate as H+ acceptor

Question 57

phosphate buffering intracellular=

Answer 57

H2PO4- as H+ donor and HPO42- as H+ acceptor

*optimum at ph close to its pka 6.86

Question 58

proteins as buffers as they are amphoteric?

Answer 58

COOH= acid, NH2=base

*proteins like haemoglobin containing HISTIDIE buffer effectively near neutral PH