Search found 26 matches
- Sat Mar 12, 2016 9:14 pm
- Forum: *Electrophiles
- Topic: General Question about Nucleophiles vs. Electrophiles
- Replies: 2
- Views: 1606
Re: General Question about Nucleophiles vs. Electrophiles
Generally, nucleophiles will also have lone pairs or double bonds as electron-rich regions. Electrophiles, on the other hand, will have open valences or be missing an electron, as they are electron-deficient.
- Sat Mar 12, 2016 4:27 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: N in Nernst Equation
- Replies: 1
- Views: 1407
Re: N in Nernst Equation
The n in the Nernst equation stands for the transfer of electrons that were used in both balanced half-reactions of the anode and cathode. For #3B of the 2011 Final, the balanced half-reaction of the anode is 4OH - + MnO 2 → MnO 4 2- + 2H 2 O + 2e - while the balanced half-reaction of the cathode co...
- Wed Mar 09, 2016 4:21 pm
- Forum: *Alcohols
- Topic: priority for naming
- Replies: 1
- Views: 738
Re: priority for naming
Ethers and halogens are not given priority as functional groups when numbering; however, alcohols still do have priority.
- Sun Mar 06, 2016 10:19 pm
- Forum: *Cycloalkenes
- Topic: Cycloalkenes as Substituents
- Replies: 1
- Views: 568
Cycloalkenes as Substituents
If a cycloalkene was a substituent off a parent chain, what would the name of the cycloalkene end in? For example, if cyclopentane becomes cyclopentyl as a substituent, would it become cyclopentenyl as a double-bonded substituent?
- Sun Mar 06, 2016 2:48 pm
- Forum: *Electrophilic Addition
- Topic: Intermediates
- Replies: 1
- Views: 470
Re: Intermediates
To my understanding, the number of intermediates refers to the actual number of intermediate molecules that are produced by the end of the first transition state. The amount of valleys only indicates the period where intermediates have been created.
- Sun Feb 28, 2016 8:58 pm
- Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
- Topic: Geometric Isomers
- Replies: 1
- Views: 682
Geometric Isomers
On page 17 of the Intro to Organic Chemistry textbook, how do you distinguish between the (E)-3,7-Dimethylocta-1,3,7-triene and (Z)-3,7-Dimethylocta-1,3,7-triene isomers? I'm thinking you start comparing at the 3 C double bond but don't know what to do beyond that? Thanks!
- Thu Feb 25, 2016 11:05 am
- Forum: *Alkanes
- Topic: Structures and Substituents
- Replies: 2
- Views: 481
Re: Structures and Substituents
Which carbon the substituent is coming off of is denoted by the number in front of the substituent in the IUPAC name. Which direction you start counting from to place the substituent doesn't matter so much when you are drawing the structure given the IUPAC name.
- Wed Feb 17, 2016 10:18 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Pseudo rate laws
- Replies: 3
- Views: 906
Re: Pseudo rate laws
Could someone also clarify what exactly a pseudo rate law is and what it is used for? Thanks!
- Mon Feb 15, 2016 5:15 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Energetically Favorable
- Replies: 1
- Views: 716
Re: Energetically Favorable
Energetically favorable reactions tend to have a negative ΔG because they decrease free energy. Being energetically favorable means the reaction releases energy and produces heat.
- Thu Feb 04, 2016 1:13 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Redox reactions
- Replies: 2
- Views: 701
Re: Redox reactions
Generally, a negative E° means the reaction is unfavorable. This is because in the equation ∆G°(redox)= -nFE°, a negative E° would yield a positive ∆G°. When ∆G° is positive, that means the reaction is not spontaneous and thereby unfavorable.
- Mon Feb 01, 2016 11:42 pm
- Forum: Balancing Redox Reactions
- Topic: Reducing and oxidizing agents
- Replies: 1
- Views: 613
Re: Reducing and oxidizing agents
Generally, atoms, ions, and molecules that have electron affinity tend to make strong oxidizing agents, such as non-metals. For example, F 2 is the strongest common oxidizing agent. Metals, on the other hand, lose electrons readily and are good reducing agents. In addition, the strengths of oxidizin...
- Sat Jan 23, 2016 5:26 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Homework problem 8.59
- Replies: 5
- Views: 2267
Re: Homework problem 8.59
The Nitrogen is disregarded because N2 is an example of a gas in its standard state, which means that its standard enthalpy of formation is 0. Other gases in standard state and with a ΔHf of 0 include O2, F2, Br2, H2, and Cl2.
- Mon Jan 18, 2016 3:55 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: molar heat capacity
- Replies: 2
- Views: 718
Re: molar heat capacity
Molecules with hydrogen bonding usually have higher molar heat capacities. Substances with strong hydrogen bonds, such as water or ammonia, take the absorbed thermal energy and store it as potential energy within the hydrogen bonds. Thus, it takes more energy to increase the kinetic energy (or incre...
- Sat Jan 09, 2016 1:20 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Enthalpy and internal energy
- Replies: 1
- Views: 478
Re: Enthalpy and internal energy
Enthalpy is the amount of heat released or absorbed in a thermodynamic system, or in other words, a change in energy in the form of heat. Internal energy, however, is the total amount of energy stored within a system, which involves both heat transferred to and work done by the system.
- Wed Dec 02, 2015 11:34 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Determining pH of aqueous KBr
- Replies: 2
- Views: 4500
Re: Determining pH of aqueous KBr
If you look at KBr, it gives off neither H+ ions nor OH- ions, because K+ does not act as an acid and Br- is a neutral conjugate base, causing KBr overall to be neutral.
- Mon Nov 23, 2015 10:38 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Disregarding the X?
- Replies: 1
- Views: 357
Re: Disregarding the X?
You can disregard x when K<10^-4.
- Wed Nov 18, 2015 8:15 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: How to find if you -x or +x for ICE
- Replies: 1
- Views: 406
Re: How to find if you -x or +x for ICE
One way would be if you are given the K value. If K is a large value or K>1 you can assume that the reaction favors the products since the products constitute the numerator in the K expression (a larger numerator compared to the denominator would mean a larger K value), and thus the reactants would ...
- Tue Nov 17, 2015 11:23 pm
- Forum: Ideal Gases
- Topic: Effects on Equilibrium constants
- Replies: 2
- Views: 645
Re: Effects on Equilibrium constants
An increase in temperature will cause an endothermic reaction to shift right and favor the product. This would create more product to make for a greater numerator in the equilibrium constant, thus, increasing the equilibrium constant. Likewise, in a forward exothermic reaction, increasing the temper...
- Fri Nov 13, 2015 2:41 pm
- Forum: Naming
- Topic: Ligand Definition
- Replies: 1
- Views: 334
Re: Ligand Definition
Yes, ligands are only applicable to transition metals. A bond between a nonmetal and a metal is an ionic bond, while a bond between nonmetals is covalent.
- Mon Nov 09, 2015 12:38 am
- Forum: Naming
- Topic: Ligands and Transition Metal Bonding
- Replies: 2
- Views: 625
Re: Ligands and Transition Metal Bonding
Are there any distinguishing characteristics of coordinate covalent bonds, aside from being a bond between a transition metal and ligand? For example, are they stronger or more stable than other types of bonds?
- Fri Oct 30, 2015 3:59 pm
- Forum: Dipole Moments
- Topic: polarity question
- Replies: 1
- Views: 526
Re: polarity question
If there is only one lone pair, the molecule should be polar. The lone pair creates asymmetry within the molecule's shape because it is more localized than bonding electrons, creating an uneven distribution of electrons and subsequently changing the overall molecular dipole moment.
- Thu Oct 22, 2015 3:24 pm
- Forum: Lewis Structures
- Topic: Bonds
- Replies: 1
- Views: 478
Re: Bonds
I believe quadruple bonds are possible; however, they usually require the elements to be in the d-orbital to form, such as transition metals.
- Wed Oct 14, 2015 11:38 am
- Forum: Properties of Electrons
- Topic: Rydberg Formula Derivation and Units for Quiz #1
- Replies: 1
- Views: 635
Re: Rydberg Formula Derivation and Units for Quiz #1
I was told only to use the equation E{n}=-\frac{hR}{n^2} . However, you can use the simplified form as long as you show how you derived it from the original equation. You should use the simplified form if you are confident in your calculations, otherwise I would suggest using the original E{n}=-\fra...
- Wed Oct 14, 2015 11:22 am
- Forum: SI Units, Unit Conversions
- Topic: Sig figs when problem only gives you "n" values [ENDORSED]
- Replies: 1
- Views: 665
Re: Sig figs when problem only gives you "n" values [ENDORSED]
Yes, you should use as many sig figs as are in the constants you use.
- Fri Oct 09, 2015 3:57 pm
- Forum: Significant Figures
- Topic: How often to round sf in multi-step calculations
- Replies: 1
- Views: 779
Re: How often to round sf in multi-step calculations
Personally, for a problem like this, I would actually rearrange the equation c=λv into v=c/λ and then plug the rearranged equation into E=hv for v in order to avoid any rounding errors. However, if you were to do it with multiple steps, my TA actually told me to round the first answer at least 2 sig...
- Mon Oct 05, 2015 12:01 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg Indeterminacy Equation
- Replies: 1
- Views: 388
Re: Heisenberg Indeterminacy Equation
Someone elaborate or correct me if I am wrong, but I believe the 4pi has to do with the ways one can express frequency. This equation specifically involves the number of cycles per second (as in Hz) but can also be considered as the number of radians covered per second so the 4pi must be involved in...