Regents Chemistry Review Class

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.  polar covalent

2.  polar covalent (bent, two bonds 2 electron pairs)

3.  Hydrogen bonding attractions.

4.  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 ---- CH4, CO2

1.  polar covalent

2.  SYMMETRICAL – non polar

3.  Van der Waals

4.  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.  Covalent coordinate

2.  Polar

3.  Dipole, H-bond

4.  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.  Non polar covalent

2.  Non polar

3.  Van der Waals

4.  I2 has greatest molar mass, highest melting and boiling points.

5.  HI is lowest

6.  NEVER conduct, no ions or mobile electrons.

7.  Cl2

Group 5 ---- Na, Au, Ag, Hg

1.  Metallic

2.  no molecules – does not apply

3.  Van der Waals – strong due to high atomic mass and many electrons.

4.  Varies with mass, with exceptions.

5.  Varies with mass, with exceptions.

6.  In all states – mobile sea of electrons

7.  Mn

Group 6 ---- SiO2, C(s) diamond

1.  Covalent network solid crystal

2.  no molecules – an atomic crystal

3.  NONE – atoms connected by real covalent bonds

4.  VERY HIGH – highest of all substances

5.  LOW

6.  nonconductive

GROUP 7 --- NaCl and NaF

1.  IONIC

2.  no molecules – ions have “ultimate” polarity.

3.  In the solid electrostatic.

4.  HIGH

5.  LOW

6.  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