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

ENTROPY

AIM:

What is ENTROPY?

DO NOW:

What are the oxidation #s in

1) HOBr

2) KClO3

ENTROPY

• ENTROPY (S): 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?

ENTROPY

• Phase changes are changes in the entropy of the molecules

• solidliquidgas

------ENTROPY• Entropy increases as

disorder of molecules increases

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 in entropy

• For a reaction, when the amt of gas being produced the overall entropy will

• Example:

SO3(g) 2SO2(g) + O2(g)

• Solutions in entropy when something is added

• in temp will entropy

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

ENTROPY

• Entropy when:

1. a solid becomes a gas

2. a solid becomes a liquid

3. a liquid becomes a gas

4. 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(S) and enthalpy (H) can tell us if a reaction will be spontaneous

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 in entropy (ex. ice melting)

• in entropy favors spontaneous reactions

ENTROPY

As carbon dioxide

sublimes, its entropy

1. decreases

2. Increases

3. remains the same

Which sample has the lowest entropy?

1. KNO3(l)

2. KNO3(s)

3. H2O(l)

4. H2O(g)

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