EX3: BOILING & MELTING POINT

Question 1

• the temperature at which the VAPOUR PRESSURE of the substance is EQUAL to the ATMOSPHERIC PRESSURE above it

Answer 1

BOILING POINT

Question 2

a liquid at a higher pressure has a _____ boiling point than a liquid at a lower atmospheric pressure

Answer 2

HIGHER

Question 3

BOILING POINT is also an indicator of the ___ of the compound

Answer 3

VOLATILITY

Question 4

what is the volatility of low boiling point

Answer 4

HIGH VOLATILE

Question 5

• at a given temperature, a compound will exist as _____ if it has a LOW NORMAL BOILING POINT

Answer 5

GAS

Question 6

• at a given temperature, a compound will exist as ______ if it has HIGHER NORMAL BOILING POINT

Answer 6

LIQUID OR SOLID

Question 7

• it occurs between one molecule and another, influences directly the boiling point and are dependent on the functional groups present on the organic compound

Answer 7

INTERMOLECULAR FORCES OF ATTRACTION

Question 8

WITHIN THE MOLECULE

Answer 8

INTRA

Question 9

BETWEEN MULTIPLE MOLECULES

Answer 9

INTER

Question 10

• WEAK INTERMOLECULAR ATTRACTION formed by induced polarization of molecules which is caused by FLUCTUATING CHARGES due to the NEARNESS OF THE MOLECULES as they vibrate

Answer 10

VAN DER WAALS DISPERSION FORCES

Question 11

VAN DER WAALS DISPERSION FORCES is commonly observed among ____

Answer 11

HYDROCARBON GROUPS

Question 12

VAN DER WAALS DISPERSION FORCES occurs only within _____ between molecules

Answer 12

SHORT DISTANCES

Question 13

• occurs among PARTIALLY IONIC or polar molecules
• these molecules contain an ASYMMETRICAL CHARGE due to the two poles of the molecule: one end is partially negative while the other end is partially positive

Answer 13

DIPOLE-DIPOLE INTERACTION

Question 14

DIPOLE-DIPOLE INTERACTION occurs among ____

Answer 14

PARTIALLY IONIC / POLAR MOLECULES

Question 15

• formed between PARTIALLY POSITIVE (H+) and an ADJACENT ELECTRONEGATIVE ATOM which bears a partial negative charge
• intermolecular hydrogen bonds tend to rise boiling point of an organic compound

basta may Hydrogen + electronegative atom**

Answer 15

HYDROGEN BONDING

Question 16

• intermolecular hydrogen bonds tend to ____ boiling point of an organic compound

Answer 16

RISE

Question 17

• takes place between molecules having OPPOSITE CHARGES and INVOLVES AN ELECTROSTATIC INTERACTION between the two opposite charges
• the functional groups which most easily ionize are AMINES and CARBOXYLIC ACIDS, such as the reaction of ammonia (NH3 with a carboxylic acid (carboxylate ion)

Answer 17

IONIC BONDING

Question 18

in IONIC BONDING, the functional groups which most easily ionize are _____ and ______

Answer 18

AMINES AND CARBOXYLIC ACID

Question 19

amino acid is acidic or basic

Answer 19

NEUTRAL bcos amino = base & acid = acid, hence, nacacancel

Question 20

intermolecular forces order

Answer 20

ionic bonding
hydrogen bonding
dipole-dipole interaction
Van der Waals dispersion forces

INAY HA DOON VA?

Question 21

the more the no. of carbon, the ___ the boiling point

Answer 21

HIGHER

Question 22

bumababa ang boiling point kapag nagkakaroon ng ___ sa carbon chain

Answer 22

BRANCHING

Question 23

✓due to MORE ENERGY that is required to overcome the INCREASED FORCES OF ATTRACTION caused by long carbon chains

Answer 23

• boiling point ↑ as the number of carbon atoms ↑

Question 24

✓ it causes the SURFACE AREA of the molecules to DECREASE thereby DECREASING THE FORCES OF ATTRACTION between individual molecules

Answer 24

• boiling point ↓ in the PRESENCE OF BRANCHING

Question 25

✓due to the ATTRACTION OF POSITIVE end of one molecule to the NEGATIVE end of another molecule

Answer 25

* boiling point ↑ as the POLARITY OF THE SUBSTANCE ↑

Question 26

✓due to DECREASE in the VAPOUR PRESURE of the liquid

Answer 26

* boiling point ↑ in the PRESENCE OF NON-VOLATILE IMPURITIES

Question 27

✓due to the INCREASE in the VAPOUR PRESSURE of the liquid

Answer 27

* boiling point ↓ in the presence of volatile impurities

Question 28

* the temperature at which a SOLID compound is DIRECTLY CONVERTED to its LIQUID STATE

Answer 28

MELTING POINT

Question 29

* a PURE CRYSTALLINE compound has a SHARP MELTING POINT and it completely melts within a narrow range of temperature NMT ____

Answer 29

0.5 - 1°C

Question 30

* if a compound melts over a VERY NARROW RANGE, it is assumed that the compound tested is relatively ____

Answer 30

PURE

Question 31

* if a compound melts over a _________, it is assumed that the compound tested is relatively PURE

Answer 31

VERY NARROW RANGE

Question 32

* the presence of _____ usually DEPRESSES the melting point and may INCREASE THE MELTING POINT RANGE

Answer 32

IMPURITIES

Question 33

in the identification of an impure compound, the actual melting point is compared to its

Answer 33

THEORETICAL MELTING POINT VALUE

Question 34

✓the presence of _____, and especially hydrogen bonding, leads to a HIGHER MELTING POINT of compounds

Answer 34

POLARITY

Question 35

________ between molecules may still affect the melting point of a compound (ionic bonding results to higher melting point)

Answer 35

INTERMOLECULAR FORCES OF ATTRACTION

Question 36

✓difference in the ________ (eg. isomers) may result to a difference in their melting points (difference in the arrangement of their structures even both are pure)

Answer 36

CONFIGUARTION OF CA COMPOUND

Question 37

BP: tert-butyl alchohol

Answer 37

82.3

Question 38

BP: chloroform

Answer 38

61.2

Question 39

BP: n-hexane

Answer 39

68.7

Question 40

BP: methanol

Answer 40

64.7

Question 41

MT: salicylic acid

Answer 41

211.0

Question 42

MT: benzoic acid

Answer 42

122.4

Question 43

MT: glucose

Answer 43

146.0

Question 44

MT: fructose

Answer 44

103.0