(Prelim) Exp 2&3 Post-LAB Flashcards
It is the range of temperature at which the solid phase changes to liquid.
Melting Point
It is the temperature at which the thermal motion of the molecules is just enough to break down the lattice structure of the crystal
Melting Point
have sharp melting point because of the symmetry in structure and
in strength of bonds.
Crystal solids
have sharp melting point and this physical property can be used to determine purity or presence of impurities.
Pure compounds
It provides a means of testing for the identity of two solids by examination of the melting
point behavior of a mechanical mixture of the two
Mixed melting points method
It is valuable at certain points for the identification of unknowns.
Mixed melting points method
the larger the molecule, the higher the melting point.
For alkanes
the more ordered the molecule, the more energy is required to break the intermolecular
forces holding the molecules together.
For solids
have a lower trend in melting points than even-numbered alkanes because even-
numbered pack well in the solid phase, forming a well-organized structure.
Odd number alkanes
have higher melting points compared to non-planar hydrocarbons with similar molecular weights
Flat shape aromatic compounds
In the periodic table, melting point decreases
from center going to the sides (left and right); decrease from top to bottom.
have very high melting points
Ionic compounds
Presence of polar and hydrogen-bonding groups on organic compounds generally leads to _____________
higher melting points
Oxalic acid
MW: 90
MP: 102
Naphthalene
MW:128
MP: 80.26
