Search found 22 matches

by Aya Ghoneum 1H
Tue Mar 08, 2016 2:43 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: 1.26, 28, and 29
Replies: 2
Views: 372

Re: 1.26, 28, and 29

To clarify, for naming an organic compound with a double bond and indicating “E” or “Z”, there will always be a longest chain on each side of the double bond. Alternatively, you may be naming “E” or “Z” with a functional group on either side of the double bond, be sure to look up a list priorities o...
by Aya Ghoneum 1H
Wed Mar 02, 2016 2:26 pm
Forum: *Alkanes
Topic: is HI a nucleophile or electrophile
Replies: 1
Views: 2240

is HI a nucleophile or electrophile

Hello! Is the molecule HI considered a nucleophile or an electrophile? I- is a nucleophile, I is an electrophile, and HI has lone pairs, so shouldn't it be a nucleophile? However HBr (a similar molecule) is an electrophile so should HI be an electrophile?
by Aya Ghoneum 1H
Tue Mar 01, 2016 12:22 pm
Forum: *Alkanes
Topic: Identifying substituents in the molecular formula
Replies: 3
Views: 445

Re: Identifying substituents in the molecular formula

Hello, double bonds take priority over alkanes, so you would need to start on the side of the molecule that would get you to number the double bond first. It doesn’t matter if the double bond is part of the main chain or just a substituent, you still need to start numbering so that you can get to it...
by Aya Ghoneum 1H
Tue Feb 23, 2016 3:42 pm
Forum: *Alkanes
Topic: Naming Clarification
Replies: 3
Views: 531

Re: Naming Clarification

When naming a non-cyclic organic compound, the first thing you should do is determine your base chain. This is the longest possible chain from head to tail (the structure and the way it is drawn can mislead you from picking the longest chain though). Then, you determine which side of your base chain...
by Aya Ghoneum 1H
Thu Feb 18, 2016 1:38 pm
Forum: Second Order Reactions
Topic: Units for Second Order
Replies: 2
Views: 850

Re: Units for Second Order

The units of k can be really helpful in a problem because they can tell you what overall order of reaction you have without even knowing any other information! For any order reaction, the units of k will always be such that the rate of the reaction equals “mol/(L*sec)” or concentration/time. So for ...
by Aya Ghoneum 1H
Thu Feb 11, 2016 7:35 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: q=?
Replies: 2
Views: 432

Re: q=?

I’ve seen that you commonly use the equation q=C(deltaT) when you are calculating the heat for a calorimeter (qcal=C(deltaT)). It’s also important to remember that qcal=-qsystem. Most other times, you use q=mC(deltaT) or q=nC(deltaT), depending if you are given heat capacities in g or moles. I hope ...
by Aya Ghoneum 1H
Wed Feb 03, 2016 3:04 pm
Forum: Balancing Redox Reactions
Topic: Half-Reactions
Replies: 3
Views: 483

Re: Half-Reactions

You will have to balance your own half reactions sometimes without being able to look them up in an Appendix. Here is a set of rules for balancing redox reactions. For balancing in an acidic solution: 1. Divide the equation into two half reactions. 2. Balance any atom other than O or H first. 3. Bal...
by Aya Ghoneum 1H
Wed Jan 27, 2016 4:58 pm
Forum: Phase Changes & Related Calculations
Topic: Quick significant figures question
Replies: 4
Views: 644

Re: Quick significant figures question

I think you only base significant figures on the values used in your calculations. (So if you didn’t actually use the value 4.2g in any of your calculations, you wouldn’t use it for determining the amount of sig figs in your answer). Additionally, it is helpful to know that you go through your entir...
by Aya Ghoneum 1H
Wed Jan 20, 2016 10:33 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Degeneracy equation
Replies: 2
Views: 476

Re: Degeneracy equation

In order to find the molar residual entropy of a system, you must use the equation S=kB ln W, where S is the molar residual entropy of the system, kB is Boltzman’s constant (1.3806 x10^-23 J/K), and W is the degeneracy of the system. I like to think of W as the number of microstates possible for the...
by Aya Ghoneum 1H
Thu Jan 14, 2016 7:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: QUIZ 1 Material
Replies: 7
Views: 963

QUIZ 1 Material

Hello,

I was wondering if Chapter 11 material (assigned in the syllabus) would be part of Quiz 1 material? Thank you very much!
by Aya Ghoneum 1H
Wed Jan 13, 2016 2:21 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.73 Bond Enthalpy of Benzene
Replies: 4
Views: 4217

Re: 8.73 Bond Enthalpy of Benzene

For Problem 8.73 and any other problem involving calculating reaction enthalpy using bond enthalpies, you need to look up tables (Table 8.7 in this case) for the bond enthalpies of the bonds being broken and formed. The total reaction enthalpy will be equal to all of the bonds being broken subtracte...
by Aya Ghoneum 1H
Wed Jan 13, 2016 2:18 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Mean Bond Enthalpy
Replies: 2
Views: 684

Re: Mean Bond Enthalpy

You’re right, there is only one mole of water molecules in the reaction, however each water molecule is made up of TWO H-O bonds (think about the Lewis structure). That is why you need to multiply the bond enthalpy for the H-O bond by 2. I hope this helps!
by Aya Ghoneum 1H
Wed Jan 06, 2016 3:38 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy values
Replies: 2
Views: 500

Re: Enthalpy values

Hello, In order to find the enthalpy of a reaction using bond enthalpies, you will need to have a chart of all bond enthalpies at hand (something like Tables 8.6 or 8.7 on Page 300 of our textbook). Then, it is important to know that the enthalpy of the reaction will be the difference between the bo...
by Aya Ghoneum 1H
Tue Dec 01, 2015 6:26 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Using the formula
Replies: 2
Views: 644

Re: Using the formula

For answering questions regarding acids/bases, I have memorized these equations. It is true that Kw=1.0*10^-14 at 25C. Additionally, you will have to be given at least one other piece of information specific to the question in order to correctly solve the other variables, such as pH, pOH, pKa, pKb, ...
by Aya Ghoneum 1H
Mon Nov 23, 2015 3:02 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Strong Acid/Base
Replies: 2
Views: 378

Re: Strong Acid/Base

Also, strong acids have higher Ka values, so they dissociate almost 100%, while weak acids have very low Ka values, which makes them only partially dissociate in solution.
by Aya Ghoneum 1H
Wed Nov 18, 2015 8:26 pm
Forum: Ideal Gases
Topic: Question about Kp vs Kc
Replies: 2
Views: 644

Re: Question about Kp vs Kc

Hello, this is true. And another thing that may be useful to mention here is a way to convert Kc to Kp (or vice versa). To do this, you use the equation given in the textbook on Page 438, where Kp= [ (cRT/P)^(delta n) ] *Kc. I hope this helps!
by Aya Ghoneum 1H
Wed Nov 11, 2015 10:38 pm
Forum: Biological Examples
Topic: Other Biologically Important Coordination Compounds
Replies: 1
Views: 500

Other Biologically Important Coordination Compounds

I was wondering what other coordination compounds are important in biological systems? For example, in our course reader, Dr. Lavelle talks about the heme molecule being an iron-based coordination compound. Also, I found on-line that Vitamin B is also a coordination compound with a cobalt metal cent...
by Aya Ghoneum 1H
Tue Nov 03, 2015 3:09 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm 2011 question 6B
Replies: 2
Views: 805

Re: Midterm 2011 question 6B

In order to rank compounds in terms of their relative ionic character, one needs to first understand the spectrum of covalent and ionic comounds. Covalent compounds share electrons, and the closer together two atoms’ electronegativities are, the better they will share their electrons. Similarly, the...
by Aya Ghoneum 1H
Sat Oct 31, 2015 7:33 am
Forum: Limiting Reactant Calculations
Topic: Limiting Reactants & Limiting Reagents [ENDORSED]
Replies: 7
Views: 2702

Re: Limiting Reactants & Limiting Reagents [ENDORSED]


Limiting Reactant.m4v [ 15.79 MiB | Viewed 2676 times ]



I have made one educational chemistry video about the limiting reactant calculation. Thank you very much. -Aya Ghoneum
by Aya Ghoneum 1H
Wed Oct 28, 2015 4:22 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: OF+
Replies: 2
Views: 5292

Re: OF+

The bond order and magnetism (paramagnetic or diamagnetic) found through molecular orbital theory is not always reflected in the Lewis structure for a molecule. Lewis structures are strictly based on valence electrons and the octet rule. They give a generic understanding of the molecule, mainly help...
by Aya Ghoneum 1H
Thu Oct 22, 2015 8:13 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs Nonpolar
Replies: 3
Views: 3483

Re: Polar vs Nonpolar

One easy way to differentiate if a molecule is polar would be that any molecules with at least one lone pair on the central atom is polar. If there are no lone pairs on the central atom and all of the surrounding atoms are equivalent, then the molecule is non-polar. If there are nonequivalent atoms ...
by Aya Ghoneum 1H
Mon Oct 05, 2015 3:05 pm
Forum: DeBroglie Equation
Topic: Atomic Spectra and Rydberg Question
Replies: 1
Views: 436

Atomic Spectra and Rydberg Question

For the homework question 1.15, "In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and ending energy levels of the electron during the emission of energy that leads to this spectral line." can I assume that the ending ...

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