REGENTS CHEMISTRY REVIEW CLASS
SUNDAY MAY 21, 2006
#1) for each group of substances, indicate the following:
1. Type of bonding and ionic character
2. Type of molecule (covalent only)
3. interparticular attractions (intermolecular for covalent)
4. RELATIVE boiling and melting points
5. vapor pressure
6. conductivity
7. other examples of this type of substance
FIRST GROUP 1 ---- H2O and H2S
1.
2.
3.
4.
polar covalent
polar covalent (bent, two bonds 2 electron pairs)
Hydrogen bonding attractions.
Water is more polar based on ionic character of 1.3, therefore stronger
H-bond attraction, has a higher boiling and melting point
5. water has a lower vapor pressure.
6. Neither forms ions, neither has mobile electrons – non conductive.
7. NH3
Group 2 ---1.
2.
3.
4.
CH4, CO2
polar covalent
SYMMETRICAL – non polar
Van der Waals
CO2 has a greater molar mass, therefore has greater Van der Waals
and has greater melting and boiling point.
5. Both high, CH4 theoretically higher.
6. Non conductors.
7. H2
Group 3---- HF, HCl
1.
2.
3.
4.
Covalent coordinate
Polar
Dipole, H-bond
HF is more polar based on ionic character, has stronger dipole
attractions higher melting and boiling.
5. HF is lower
6. The acids on the reference tables K do ionize and are conductors in
solution.
7. HBr
Group 4---- H2, F2, I2
1.
2.
3.
4.
5.
6.
7.
Non polar covalent
Non polar
Van der Waals
I2 has greatest molar mass, highest melting and boiling points.
HI is lowest
NEVER conduct, no ions or mobile electrons.
Cl2
Group 5 ---- Na, Au, Ag, Hg
1.
2.
3.
4.
5.
6.
7.
Metallic
no molecules – does not apply
Van der Waals – strong due to high atomic mass and many electrons.
Varies with mass, with exceptions.
Varies with mass, with exceptions.
In all states – mobile sea of electrons
Mn
Group 6 ---- SiO2, C(s) diamond
1.
2.
3.
4.
5.
6.
Covalent network solid crystal
no molecules – an atomic crystal
NONE – atoms connected by real covalent bonds
VERY HIGH – highest of all substances
LOW
nonconductive
GROUP 7 --- NaCl and NaF
1.
2.
3.
4.
5.
6.
IONIC
no molecules – ions have “ultimate” polarity.
In the solid electrostatic.
HIGH
LOW
conductive as liquids(l) and in solutions (aq), NOT SOLID STATE
CONDUCTORS.
7. MgCl2
#2)For each of the following REVERSABLE PROCESSES please;
1. Draw the process using symbols to represent the particles
before and after the physical process.
2. Indicate the energy flow, endo or exothermic.
3. Discuss the word equilibrium
4. Indicate the sign of ∆H, ∆S and ∆G
5. the role of attractions and energy for each process.
A) Melting and freezing
B) Evaporation and condensation
C) Sublimation and Deposition
#3) Indicate the flow of energy in between the heat source and heat sink,
describe the equation q = mass * ∆T * specific heat