POC LAB - Boiling and Melting Point

Boiling Point

temperature at which the vapour pressure (substance) is equal to the atmospheric pressure

volatility

tendency of a substance to evaporate rapidly or unpredictably

Directly Proportional

relationship between Atmospheric pressure and boiling point

Indirectly Proportional

relationship between boiling point and volatility

gas

compound will exist if it has low normal boiling point

liquid/solid

compound will exist if it has higher normal boiling point

intermolecular forces of attraction

influences directly the boiling point and is dependent on the functional groups present in the organic compound

Van Der Waals Dispersion Forces

(Weak IMA forms Induced Polarization); occurs in hydrocarbon groups and within short distances in between molecules

Dipole-Dipole Interaction

(Asymmetrical Charge);Occurs in partially ionic or polar molecules

Hydrogen Bonding

Rises boiling point; formed between (H+) and negative charged electronegative atom

Ionic Bond

occurs in opposite charges having a electrostatic interaction; found in amines and carboxylic acids

Ionic - Hydrogen Bonding - Dipole-Dipole Interaction - Van der Waals Dispersion Forces

Order of Intermolecular Forces [I Hyde the Dip In the Van]

Directly Proportional

relationship between boiling point and the number of carbon atoms

Decreases

boiling point in the presence of branching

Directly Proportional

Relationship between Boiling point with its polarity

Increases

boiling point in the presence of non volatile impurities

Indirectly Proportional

Relationship between boiling point and volatile impurities

Melting Point

Temperature which solids become liquid

NMT 0.5-1°C

temperature which pure crystalline melts

82.3 °C

Theoretical Boiling Point of tert-butyl alcohol

61.2 °C

Theoretical Boiling Point of chloroform

68.7 °C

Theoretical Boiling Point of n-hexane

64.7 °C

Theoretical Boiling Point of methanol

211.0 °C

Theoretical Melting Point of salicylic acid

122.4 °C

Theoretical Melting Point of benzoic acid

146.0 °C

Theoretical Melting Point of glucose

103.0 °C

Theoretical Melting Point of fructose