Search found 33 matches

by Daniel Minassian 2D
Sat Mar 12, 2016 5:21 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Most stable conformation of 1-chloro-1-ethylcyclohexane
Replies: 2
Views: 624

Re: Most stable conformation of 1-chloro-1-ethylcyclohexane

However, on the Winter 2014 Final #7E, for the Newman projection the most stable conformation has a Chlorine atom staggered next to a nitrile group whereas it is the trihydroxy group that is farthest away for the most stability. Chlorine is bigger than oxygen but there are more atoms in the trihydro...
by Daniel Minassian 2D
Sat Mar 12, 2016 5:14 pm
Forum: *Alcohols
Topic: Phenol example
Replies: 3
Views: 1318

Re: Phenol example

In reading over this thread I had a question: If we were given something that looked like a benzene ring (including phenols but also not phenols) and asked to name functional groups would we not be able to call the benzene double bonds alkene functional groups because they are in resonance?
by Daniel Minassian 2D
Sat Mar 12, 2016 5:09 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Winter 2015 Final Q7B
Replies: 1
Views: 376

Re: Winter 2015 Final Q7B

Draw out the reaction profile and on it write everything you know (including up/down arrows like they are drawn in example problems). Then you will notice that the reverse activation energy will be going from Products all the way to the top of the hump in the middle of the graph. This is composed of...
by Daniel Minassian 2D
Sat Mar 12, 2016 4:54 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Winter Practice Final 2015 9B
Replies: 3
Views: 486

Re: Winter Practice Final 2015 9B

The functional group gets first priority consideration. The longest chain rule would only apply in this case if there was no functional group present.
by Daniel Minassian 2D
Sat Mar 12, 2016 9:48 am
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Winter 2013 Q. 8C
Replies: 1
Views: 384

Winter 2013 Q. 8C

How do we know what conformation a Newman projection indicates? The question shows the chair conformation of cyclohexane. How would the boat conformation look like, drawn using a Newman projection? If I wanted to add substituents, such as a methyl group or halogen, where would they go for the most s...
by Daniel Minassian 2D
Sat Mar 12, 2016 9:43 am
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Most stable conformation of 1-chloro-1-ethylcyclohexane
Replies: 2
Views: 624

Most stable conformation of 1-chloro-1-ethylcyclohexane

If you have a halogen and an ethyl substituent attached to the same carbon on cyclohexane, would you seek to make the halogen equatorial or the ethyl group equatorial. The halogen will take up more space but the ethyl has multiple atoms.
by Daniel Minassian 2D
Tue Mar 08, 2016 10:29 pm
Forum: *Alcohols
Topic: Homework 2.48- Systematic or Common
Replies: 1
Views: 344

Re: Homework 2.48- Systematic or Common

I would agree with you except, since the numbering can be either 2,5 or 5,2 (and these numbers do not signify the position of the alcohol which is assumed to be attached to carbon atom 1), I believe it should be 2-methylethyl-5-methylcyclohexanol so that the lower number appears first (this rule onl...
by Daniel Minassian 2D
Mon Feb 29, 2016 8:54 pm
Forum: *Alkanes
Topic: Condensed Structural formula vs. structural formula
Replies: 1
Views: 424

Condensed Structural formula vs. structural formula

How can you tell when the species in parenthesis in the structural/condensed structural formula are part of the main chain or are explicitly substituents, as the questions do not differentiate between structural and condensed structural formula?
by Daniel Minassian 2D
Sat Feb 27, 2016 1:10 pm
Forum: *Organic Reaction Mechanisms in General
Topic: How Catalysts Lower the standard entropy of activation
Replies: 1
Views: 354

How Catalysts Lower the standard entropy of activation

How is it that a catalyst makes the standard entropy of activation less negative by bringing the reactants together before reaction and placing them in the correct orientation. Doesn't this result in less randomness in the system? In that case, wouldn't it only make this value more negative?
by Daniel Minassian 2D
Thu Feb 25, 2016 10:38 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Significance of (S) and (R) isomer in intermediates
Replies: 1
Views: 292

Significance of (S) and (R) isomer in intermediates

This question is with respect to pg. 156 in the Intro to Organic Chemistry Book. In this page it shows two isomers of butan-2-ylium. I do not understand why there are two isomers as it seems the molecule is simply rotated around. I was under the impression from the lectures that flipping around a li...
by Daniel Minassian 2D
Mon Feb 22, 2016 9:09 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Order of Catalyzed Reactions
Replies: 1
Views: 394

Order of Catalyzed Reactions

Seeing how 15.67 is solved in the solutions manual, is there a general assumption made that reactions that are catalyzed are first-order reactions?
by Daniel Minassian 2D
Thu Feb 18, 2016 3:38 pm
Forum: First Order Reactions
Topic: Rate Law Units
Replies: 1
Views: 419

Re: Rate Law Units

This really depends on what the units given in the problem are and if they ask for any specific units. As long as your units are consistent you can report in the values you like. There is no rule mandating that k always be reported in seconds, though this may or may not be the norm. I would imagine ...
by Daniel Minassian 2D
Tue Feb 09, 2016 4:39 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Going from Reaction to Cell Diagram
Replies: 1
Views: 329

Going from Reaction to Cell Diagram

This question refers to Example 14.7 on page 584 of the textbook. Why does the cell diagram include H+(aq) on both sides? It is not being reduced or oxidized. Why is it included in the cell diagram? Also regarding the order of things inside the cell diagram: I know that anode is on the left and cath...
by Daniel Minassian 2D
Tue Feb 09, 2016 4:31 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing a Cell Reaction from Cell Diagram
Replies: 1
Views: 382

Writing a Cell Reaction from Cell Diagram

This question refers to Example 14.4 on page 576 of the textbook. I am asked to write a reaction for the cell Pt(s)|H 2 (g)|HCl(aq)|Hg 2 Cl 2 (s)|Hg(l). None of the half-reactions provided by the cell include HCl. I understand that it would be dissociated but the only dissociated Cl- in the example ...
by Daniel Minassian 2D
Thu Feb 04, 2016 10:14 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: physical diagram
Replies: 1
Views: 251

Re: physical diagram

The salt bridge and porous disk carry out the same function. They prevent charge buildup by allowing the shuttling of ions from one side to the other. As the anode becomes more and more positive, the negative ions that don't participate in the reaction (I believe they are called spectator ions) move...
by Daniel Minassian 2D
Sun Jan 31, 2016 12:00 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Writing Equation and K value from Partial Pressure
Replies: 1
Views: 287

Writing Equation and K value from Partial Pressure

This question refers to #89 in Ch.11 HW. I understand most of the problem. What I do not understand is the value of each partial pressure is divided by 100.
by Daniel Minassian 2D
Wed Jan 27, 2016 7:49 pm
Forum: Phase Changes & Related Calculations
Topic: CONSTANT TEMPERATURE?
Replies: 2
Views: 414

Re: CONSTANT TEMPERATURE?

During a phase change all the energy that is applied goes towards breaking up the bonds/forces keeping the substance together in its current state.
by Daniel Minassian 2D
Tue Jan 19, 2016 4:29 pm
Forum: Phase Changes & Related Calculations
Topic: Specific Heat Capacity in Different Phases
Replies: 1
Views: 685

Re: Specific Heat Capacity in Different Phases

No, this is not true of all substances. In fact, water is the best example of this. The specific heat capacity of water in its liquid state is higher than the specific heat of water in solid form and in vapor form.
by Daniel Minassian 2D
Sun Jan 17, 2016 1:36 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Relationships of Enthalpy with Change in Internal Energy
Replies: 1
Views: 291

Relationships of Enthalpy with Change in Internal Energy

The textbook states that if there is a net change in moles of gas in a reaction then the enthalpy of the reaction is not the same as the change in internal energy of the system because work is done. If the reaction is done under constant volume, then can the change in internal Energy be said to be e...
by Daniel Minassian 2D
Sat Jan 16, 2016 8:33 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Stability of Benzene from Bond Enthalpy vs. Delocalization
Replies: 1
Views: 557

Stability of Benzene from Bond Enthalpy vs. Delocalization

This question is in reference to #77 on the Homework. The added bond enthalpies for 6 C-C bonds with resonance is greater than that of 3 C=C bonds and 3 C-C single bonds. Why does this imply that Benzene is more stable with resonance than without it? I thought the delocalization of electrons on the ...
by Daniel Minassian 2D
Thu Jan 14, 2016 10:39 pm
Forum: Phase Changes & Related Calculations
Topic: Isothermal Reversible Work Calculation Clarifications
Replies: 3
Views: 546

Re: Isothermal Reversible Work Calculation Clarifications

You are given an initial Pressure, Temperature, and Volume. You cannot use final volume with initial Pressure and initial Temperature in the same equation. It wouldn't make sense. Use initial volume with the rest of the "initials" and then you will find the initial number of moles of gas (...
by Daniel Minassian 2D
Fri Jan 08, 2016 7:41 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Intensive properties
Replies: 2
Views: 1989

Re: Intensive properties

It is important to note that heat capacity in itself is an extensive property, that is, the value of this property depends on the amount of substance present. It is also important to note that (according to pg.269 in the textbook): C s *m = C. You can see from this equation that heat capacity is ext...
by Daniel Minassian 2D
Tue Dec 01, 2015 8:56 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Both Species of a Buffer System being present as salts
Replies: 1
Views: 332

Both Species of a Buffer System being present as salts

This question is in reference to HW problem #19 for Ch. 13, specifically part b and c. What is the difference between NaH 2 PO 4 and Na 2 HPO 4 as the acid/conjugate base pair in the buffer system as opposed to the "plain species" (i.e. without the sodium atoms) ? In the other problems, th...
by Daniel Minassian 2D
Fri Nov 27, 2015 7:35 pm
Forum: Identifying Acidic & Basic Salts
Topic: Identification
Replies: 1
Views: 435

Re: Identification

Those are good ions to remember. However, keep in mind as a general rule that cations of BOTH Group 1 and Group 2 metals, plus other cations with a +1 charge are too large or have too low a charge to significantly polarize the water molecules they are surrounded by and thus do not affect pH. With re...
by Daniel Minassian 2D
Mon Nov 16, 2015 4:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Using Equilibrium Partial Pressure to find Volume
Replies: 1
Views: 264

Using Equilibrium Partial Pressure to find Volume

This question refers to #66 in the homework for Ch. 11. My question is why does Dalton's law of partial pressures not need to be used to calculate the volume of the container inside which an equilibrium reaction involving gases takes place? Why is it that the volume can be calculated using only one ...
by Daniel Minassian 2D
Fri Nov 13, 2015 3:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Dissociation of a diatomic molecule over time
Replies: 1
Views: 377

Dissociation of a diatomic molecule over time

This question refers to homework #7 in Ch. 11. How do I know which flask represents equilibrium? Also, why is mole fraction necessary when calculating K for decomposition?
by Daniel Minassian 2D
Thu Nov 05, 2015 1:23 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Can oxalate ion be monodentate?
Replies: 1
Views: 517

Can oxalate ion be monodentate?

This is in reference to HW # 17.33. I see how due to the Lewis structure of the oxalate ion this molecule can be bidentate. However, given that the carbonate ion can be either monodentate or bidentate, why is it that the oxalate ion is primarily bidentate? What decides whether it can be bidentate vs...
by Daniel Minassian 2D
Fri Oct 30, 2015 2:35 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Why are names of a few chemical species reversed in struct?
Replies: 1
Views: 301

Why are names of a few chemical species reversed in struct?

In the coordination compound [NiCl2(NH3)4] why are the names of two ammonia molecules attached to Ni written backwards? Is there anything different implied by this: H3N?
by Daniel Minassian 2D
Sun Oct 25, 2015 12:06 pm
Forum: Octet Exceptions
Topic: Radical Lewis Diagram 3.59a
Replies: 2
Views: 524

Re: Radical Lewis Diagram 3.59a

I am also confused with regards to this lewis structure. Also, Cl does have access to the d orbital because it is in the 3rd period of the periodic table. Notable atoms with access to expanded octets would include S, P, and Cl. It says the same thing in the course reader pg. 72
by Daniel Minassian 2D
Fri Oct 23, 2015 11:48 am
Forum: Octet Exceptions
Topic: Why does Sulfur accommodate expanded octet?
Replies: 2
Views: 3764

Why does Sulfur accommodate expanded octet?

Why is it that Oxygen, which is in the same group as Sulfur, cannot accommodate an expanded octet but Sulfur can?
by Daniel Minassian 2D
Fri Oct 09, 2015 10:06 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Orbitals
Replies: 1
Views: 294

Re: Orbitals

Mathematically speaking, the angular momentum quantum number increases as you move from s, p, d, to f. This translates to the s orbital being able to penetrate the inner shells (i.e. the s electrons can go very close to the nucleus). The higher angular momentum quantum numbers for the other orbitals...
by Daniel Minassian 2D
Fri Oct 09, 2015 9:52 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Thorium
Replies: 1
Views: 474

Re: Thorium

I had the same question. However, if it makes any difference, it was announced on the website that 2.45 (D) on the HW, which corresponds to your question should be skipped.
by Daniel Minassian 2D
Thu Oct 01, 2015 10:29 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Determining correct values for n in the Rydberg Equation
Replies: 1
Views: 4220

Determining correct values for n in the Rydberg Equation

Problem #15 in the Chapter 1 exercises of the textbook states: "In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line."...

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