Exam 1B Units 4 + 5 - How Do We Characterize & Predict Chemical Processes?

A higher charge means a stronger bond in that molecule

A highly charged molecule reflects what when compared to a weaker charged molecule?

High potential energy means a molecule is weaker in its bond strength

A molecule with a high potential energy reflects what about its strength

A smaller molecule will be stronger and have lower potential energy

A larger sized molecule when compared to a smaller one reflects what about its strength and potential energy?

absorbs energy

When a bond breaks, it _______ energy

releases energy

When a bond forms, it _______ energy

Exothermic
Releasing energy

AA —> AB

Endothermic
Absorbing energy

AB —> AA

Exothermic

Which type of energy reaction is product favored (energetically favored)

Endothermic

Which type of energy reaction is reactant favored

Whether or not the product or reactant has the lower potential energy

Favorability is based on what in energy reactions

Lower temperature

A lower Ep product would be favored at what temp

Higher temperature

A higher Ep product would be favored at what temp

Lower left and upper right quadrant

Which quadrants of a PEC diagram would be temperature dependent

Upper left quadrant

Which quadrant of a PEC diagram would be least favored (doesn’t happen at any temperature)

Less gas —> more gas
Entropically favored

ΔS>0 indicates what?

More gas —> less gas
Entropically UNfavored

ΔS<0 indicates what?

Least stable and therefore more Ep and therefore less of a charge when compared to a molecule of a smaller size.

A largely sized molecule indicates what about its stability?

Increasing the Ep

Increasing entropic stability means what in terms of Ep?

Move to a lower Ep

For a reaction to be energetically favored (∆H<0)

Energetically stable (favored)

Substances with a lower Ep are _____

Entropically stable (favored)

Substances with a higher entropy are _____

Move to a higher number of configurations

For a reaction to be entropically favored (∆S>0)

A product favored reaction would have a higher concentration of products

A reactant favored reaction would have a higher concentration of reactants

Favorable means more likely to happen = requires no energy

Favorability implies what in terms of concentrations when a reaction stops changing

Lower right

Which quadrant of a PEC diagram would be most favored (happens at all temperatures)

Higher entropy and therefore more stable

A higher molar mass indicates what in terms of entropic stability?

What can we conclude about favorability based on this graph?

At all temperatures, ∆G is always (-)
Always product favored

What can we conclude about favorability based on this graph?

At all temperatures, ∆G is (+)
Always reactant favored

What can we conclude about favorability based on this graph?

At low tempuratures ∆G is (+); at higher temperatures ∆G is (-)
Product favored at high temperature

What can we conclude about favorability based on this graph?

At low temperatures ∆G is (-), at higher temperatures ∆G is (+)
Product favored at low temperatures