# Orgo Ch 4.4-4.6

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1. __ is the branch of chem that deals with the energy changes accompanying chemical and physical transformations. These energy changes are most useful for describing the properties of systems at __.
• thermodynamics
• equilibrium
2. The equilibrium concentrations of reactants and products are governed by the __ of the reaction.
How is the equation set up?
• equilibrium constant
• concentration of products/ concentration of reactants (the moles would be the powers)
3. The values of Keq tells us what?
the position of the equilibrium: whether the products or reactants are more stable, adn therefore energetically favored
4. If Keq is larger than one, what? less than one?
• the reaction is favored as written from left to right
• the reverse reaction is favored (from right to left as written)
5. When the Keq is extremely large, what? The value of Keq is a measure of what?
• the reaction is said to go to completion
• the reaction's tendency to go to completion
6. From the value of Keq we can calculate the change in __ (sometimes called __) that accompanies the reaction. __ is represented by __ and the change (__) in free energy is associated with a reaction represented by __, the difference between the free energy of the products and the free energy of the reactants.
• free energy
• Gibbs free energy
• free energy
• G
• Δ
• ΔG
7. ΔG is a measure of what?
• the amount of energy available to do work
• = (free energy of products)-(free energy of reactants)
8. If the energy levels of the products are lower than the energy levels of the reactants, then what?
the reaction is energetically favored; and this equation gives a negative value of ΔG, corresponding to a decrease in the energy of the system
9. The __ is most commonly used. The symbol o designates __.
• standard Gibbs free energy change (ΔGo)
• a reaction involving reactants and products in their standard state
10. The relationship between ΔGo and Keq is given by the expression?
Explain the values too.
Keq= e^(-ΔGo/RT)

• R= 8.314 J/ kelvin-mol
• T= absolute temp in K
11. The formula shows that a reaction is favored if what?
A reaction that has a __ is what?
These predictions agree with our intuition that reactions should go from __ to __ with a net __ in __
• it has a negative value
• positive value of ΔGo
• unfavorable
• higher-energy states
• lower-energy states
• decrease
• free energy
12. In general, a reaction goes __ for values of ΔGo that are more negative than about -12 kJ/ mol.
nearly to completion
13. Two factors contribute to the change in free energy:
• the change in enthalpy and the change in entropy multipled by the temperature
• ΔGo= ΔHo-TΔS
• ΔGo= (free energy of products)-(free energy of reactants)
• ΔHo= (enthalpy of products)-(enthalpy of reactants)
• ΔSo= (entropy of products)-(entropy of reactants)
14. At low temps, the __ usually much larger than the __, and the __ is sometimes ignored.
• enthalpy term (ΔHo)
• entropy
• entropy term
15. The __ is the heat of reaction-- the amount of heat evolved or consumed in the course of a reaction, usually given in kj per mole. The __ is a measure of the relative __ in the products and reactants. Reactions tend to favor products with the __ (those with the __).
• change in enthalpy
• enthalpy change
• strength of bonding
• lowest enthalpy
• strongest bonds
16. If weaker bonds are broken and stronger bonds are formed, heat is evolved and the reaction is __. In an __ reaction, the __ term makes a favorable negative contribution to ΔGo.
• exothermic x2
• enthalpy
17. If stronger bonds are broken and weaker bonds are formed, then energy is consumed in the reaction, and the reaction is __. In an __ reaction, the __ term makes an unfavorable positive contribution to ΔGo.
• endothermic x2
• enthalpy
18. __ is often described as randomness, disorder, or freedom of motion. Reactions tend to favor products with the __.A __ value of the __ change (ΔSo), indicating that the products have more freedom of motion than the reactions, makes a favorable (negative) contribution to ΔGo.
• entropy
• greatest entropy
• positive
• entropy change
19. In many cases, the __ is much larger than the __, and the __ term dominates the equation for ΔGo. Thus, a __ value of ΔSo does not necessarily mean that the reaction has an __ value of ΔGo.
• enthalpy change
• entropy change
• enthalpy term
• negative
• unfavorable
20. The formation of strong bonds (the __) is usually the most important component in the driving force for a reaction.
change in enthalpy
21. The __ is the largest factor in the driving force for chlorination. This is the case in most organic reactions: The __ term is often small in relation to the __ term.
• enthalpy change
• entropy
• enthalpy
22. When discussing chemical reactions involving breaking and forming of bonds, we can use the values of the __, under the assumption that ΔGo=ΔHo. However, this may not always be the case because some may have larger changes in entropy and small changes in enthalpy.
enthalpy changes
 Author: DesLee26 ID: 237766 Card Set: Orgo Ch 4.4-4.6 Updated: 2013-10-01 02:21:45 Tags: CHM 201 Folders: Description: Price Show Answers: