EX3: BOILING & MELTING POINT Flashcards

1
Q
  • the temperature at which the VAPOUR PRESSURE of the substance is EQUAL to the ATMOSPHERIC PRESSURE above it
A

BOILING POINT

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2
Q

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

A

HIGHER

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3
Q

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

A

VOLATILITY

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4
Q

what is the volatility of low boiling point

A

HIGH VOLATILE

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5
Q
  • at a given temperature, a compound will exist as _____ if it has a LOW NORMAL BOILING POINT
A

GAS

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6
Q
  • at a given temperature, a compound will exist as ______ if it has HIGHER NORMAL BOILING POINT
A

LIQUID OR SOLID

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7
Q
  • it occurs between one molecule and another, influences directly the boiling point and are dependent on the functional groups present on the organic compound
A

INTERMOLECULAR FORCES OF ATTRACTION

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8
Q

WITHIN THE MOLECULE

A

INTRA

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9
Q

BETWEEN MULTIPLE MOLECULES

A

INTER

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10
Q
  • 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
A

VAN DER WAALS DISPERSION FORCES

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11
Q

VAN DER WAALS DISPERSION FORCES is commonly observed among ____

A

HYDROCARBON GROUPS

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12
Q

VAN DER WAALS DISPERSION FORCES occurs only within _____ between molecules

A

SHORT DISTANCES

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13
Q
  • 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
A

DIPOLE-DIPOLE INTERACTION

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14
Q

DIPOLE-DIPOLE INTERACTION occurs among ____

A

PARTIALLY IONIC / POLAR MOLECULES

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15
Q
  • 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**

A

HYDROGEN BONDING

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16
Q
  • intermolecular hydrogen bonds tend to ____ boiling point of an organic compound
A

RISE

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17
Q
  • 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)
A

IONIC BONDING

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18
Q

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

A

AMINES AND CARBOXYLIC ACID

19
Q

amino acid is acidic or basic

A

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

20
Q

intermolecular forces order

A

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

INAY HA DOON VA?

21
Q

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

A

HIGHER

22
Q

bumababa ang boiling point kapag nagkakaroon ng ___ sa carbon chain

A

BRANCHING

23
Q

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

A
  • boiling point ↑ as the number of carbon atoms ↑
24
Q

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

A
  • boiling point ↓ in the PRESENCE OF BRANCHING
25
Q

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

A
  • boiling point ↑ as the POLARITY OF THE SUBSTANCE ↑
26
Q

✓due to DECREASE in the VAPOUR PRESURE of the liquid

A
  • boiling point ↑ in the PRESENCE OF NON-VOLATILE IMPURITIES
27
Q

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

A
  • boiling point ↓ in the presence of volatile impurities
28
Q
  • the temperature at which a SOLID compound is DIRECTLY CONVERTED to its LIQUID STATE
A

MELTING POINT

29
Q
  • a PURE CRYSTALLINE compound has a SHARP MELTING POINT and it completely melts within a narrow range of temperature NMT ____
A

0.5 - 1°C

30
Q
  • if a compound melts over a VERY NARROW RANGE, it is assumed that the compound tested is relatively ____
A

PURE

31
Q
  • if a compound melts over a _________, it is assumed that the compound tested is relatively PURE
A

VERY NARROW RANGE

32
Q
  • the presence of _____ usually DEPRESSES the melting point and may INCREASE THE MELTING POINT RANGE
A

IMPURITIES

33
Q

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

A

THEORETICAL MELTING POINT VALUE

34
Q

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

A

POLARITY

35
Q

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

A

INTERMOLECULAR FORCES OF ATTRACTION

36
Q

✓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)

A

CONFIGUARTION OF CA COMPOUND

37
Q

BP:
tert-butyl alchohol

A

82.3

38
Q

BP:
chloroform

A

61.2

39
Q

BP:
n-hexane

A

68.7

40
Q

BP:
methanol

A

64.7

41
Q

MT:
salicylic acid

A

211.0

42
Q

MT:
benzoic acid

A

122.4

43
Q

MT:
glucose

A

146.0

44
Q

MT:
fructose

A

103.0