Regents Warm-Up

1
Regents Warm-Up

• Which two characteristics are associated with
  metals?
• (1) low first ionization energy and low
  electronegativity
• (2) low first ionization energy and high
  electronegativity
• (3) high first ionization energy and low
  electronegativity
• (4) high first ionization energy and high
  electronegativity

2
ENTROPY

• AIM
• What is ENTROPY?
• DO NOW
• What are the oxidation s in
• HOBr
• KClO3

3
ENTROPY

• ENTROPY (DS) a measure of the randomness or
  disorder in a system.
• A system with more disorder has a greater entropy
• What are some examples of entropy?

4
ENTROPY

• Phase changes are changes in the entropy of the
  molecules
• solid?liquid?gas
• ------ENTROPY?
• Entropy increases as disorder of molecules
  increases

5
ENTROPY

• Changes occur so the highest possible entropy is
  reached.
• Increases in entropy favor SPONTANEOUS RXNS
• Does dissolving a gas in a liquid (soda) increase
  or decrease entropy?
• This causes a i in entropy

• For a reaction, when the amt of gas being
  produced h the overall entropy will h
• Example
• SO3(g) ? 2SO2(g) O2(g)
• Solutions h in entropy when something is added
• h in temp will h entropy

6
ENTROPY

• Which sample has the greatest entropy?
• 1. NH3(g)
• 2. NH3(s)
• 3. NH3(l)
• 4. NH3(aq)

• Which process is
• accompanied by a
• decrease in entropy?
• 1. boiling of water
• 2. subliming of iodine
• 3. condensing of water vapor
• 4. melting of ice

7
ENTROPY

• Entropy h when
• a solid becomes a gas
• a solid becomes a liquid
• a liquid becomes a gas
• Something is broken into smaller pieces

• In our bodies the desire to become disordered is
  counteracted by all the energy and heat we
  produce
• Therefore, changes in entropy(DS) and enthalpy
  (DH) can tell us if a reaction will be spontaneous

8
ENTROPY

• A system tends to change toward lower enthalphy
  and higher entropy
• Spontaneous reactions occur naturally and favor
  product formation

• Some reactions may depend on conditions for
  example
• C6H12O6(s)? CO2(g)H2O(g)
• Some endothermic reactions are spontaneous due to
  an h in entropy (ex. ice melting)
• h in entropy favors spontaneous reactions

9
ENTROPY

• As carbon dioxide
• sublimes, its entropy
• 1. decreases
• 2. Increases
• 3. remains the same

• Which sample has the lowest entropy?
• KNO3(l)
• KNO3(s)
• H2O(l)
• H2O(g)

10
ENTROPY

• At STP, a sample of which element has the highest
  entropy?
• 1. Na(s)
• 2. Br2(l)
• 3. Hg(l)
• 4. F2(g)

• Which list of the phases of H2O is arranged in
  order of increasing entropy?
• 1. ice, steam, and liquid water
• 2. steam, liquid water, and ice
• 3. ice, liquid water, and steam
• 4. steam, ice, and liquid water