Search found 32 matches

by Edris Saadat 1A
Fri Mar 11, 2016 10:24 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: What is A in the Arrhenius equation?
Replies: 2
Views: 454

What is A in the Arrhenius equation?

Do we just assume 1 or do we need to solve for it?
by Edris Saadat 1A
Sun Mar 06, 2016 9:55 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Staggered vs eclipsed
Replies: 3
Views: 578

Staggered vs eclipsed

Can someone clarify the differences between these two?
by Edris Saadat 1A
Mon Feb 29, 2016 3:18 pm
Forum: *Electrophilic Addition
Topic: How many intermediates are there in electrophilic additions?
Replies: 5
Views: 746

How many intermediates are there in electrophilic additions?

Is it always 1 intermediate or can there be more than one?
by Edris Saadat 1A
Sun Feb 28, 2016 1:42 pm
Forum: *Alkanes
Topic: How to choose longest carbon chain?
Replies: 1
Views: 260

How to choose longest carbon chain?

When a problem has two carbon chains with equal lengths, how do we choose which carbon chain to use? Does it matter or do we just go with the chain that gives the most substituents?
by Edris Saadat 1A
Sat Feb 27, 2016 12:25 pm
Forum: *Alkenes
Topic: Can we draw line structures in multiple ways?
Replies: 2
Views: 382

Can we draw line structures in multiple ways?

Is there only one way to draw a line structure or is there multiple ways to draw the same molecule? Such as problem 1.13 C.
by Edris Saadat 1A
Thu Feb 25, 2016 6:38 pm
Forum: *Alkanes
Topic: Parenthesis around some carbons?
Replies: 2
Views: 379

Parenthesis around some carbons?

What does it mean when there is a parenthesis around a carbon chain? Like problem 1.12 B:

CH3CH2C(CH3)2CCH

Why does the CH3 have parenthesis around it? Does it mean its a substituent or does it have no meaning?
by Edris Saadat 1A
Tue Feb 23, 2016 1:53 pm
Forum: Second Order Reactions
Topic: Rate of reaction when given total time
Replies: 1
Views: 270

Rate of reaction when given total time

On Tuesdays quiz 2 #5C, what equation do we use to find the rate of the reaction? The question asks

"If the spectrometer were run for a total of 20 minutes, what is the rate of the rxn when you retrieve the sample from the instrument?"
by Edris Saadat 1A
Tue Feb 23, 2016 1:50 pm
Forum: Second Order Reactions
Topic: Overall rate constant
Replies: 1
Views: 1334

Overall rate constant

From Tuesday quiz 2 #7: "Suppose you somehow synthesized an unknown compound X from 3 reactants (A/B/C). The chemical eqn is given: A+B+C->X. The three plots below show the relationship between concentrations of each reactant vs time given that the other two reactants are in large excess. Find ...
by Edris Saadat 1A
Thu Feb 18, 2016 6:00 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Effect of cell size and precipitation on potential
Replies: 1
Views: 321

Effect of cell size and precipitation on potential

From the midterm q8:

"What would be the effect on the potential of this cell if sodium sulfide was added to the Cd2+ half cell and CdS were percipitatd? Why?"

"What would be the effect on the potential of the cell if he size of the silver electrode were doubled? Why?"
by Edris Saadat 1A
Mon Feb 15, 2016 1:08 pm
Forum: First Order Reactions
Topic: Initial Rate
Replies: 1
Views: 302

Initial Rate

When an initial rate doubles, do you always assume its a first order reaction?
by Edris Saadat 1A
Mon Feb 08, 2016 4:51 pm
Forum: Balancing Redox Reactions
Topic: 2009 Mid term #7
Replies: 1
Views: 309

2009 Mid term #7

Balance the following redox rxn that occurs under acidic conditions.

Cr2O72-(aq) + H2(g) --> Cr3+(aq)

Im having trouble following the steps for balancing redox reactions. Can someone explain the basic steps for balancing the reaction?
by Edris Saadat 1A
Sun Feb 07, 2016 6:48 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Mid term 2011 #6
Replies: 2
Views: 354

Mid term 2011 #6

How exactly are we supposed to determine the largest voltage for the problem? Do we pick the two extreme values or is there another way to determine it?
by Edris Saadat 1A
Thu Feb 04, 2016 2:50 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sign of entropy
Replies: 1
Views: 272

Sign of entropy

From the quiz one preparation, what is the answer supposed to be for 8C. The question asks "What is the sign on \Delta S for the following reactionss: NaCl(s) -> Na + (aq) + Cl - (aq). Explain why." I wrote that delta S would increase, but I got marked wrong. Im assuming my explanation was...
by Edris Saadat 1A
Sun Jan 24, 2016 6:20 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Higher molar heat capacity
Replies: 1
Views: 215

Higher molar heat capacity

Without looking at reference tables, how can you determine which molecule would have a higher molar heat capacity? Would the number of bonds effect the molar heat capacity?
by Edris Saadat 1A
Tue Jan 19, 2016 5:22 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond enthalpy vs mean bond enthalpy
Replies: 2
Views: 317

Bond enthalpy vs mean bond enthalpy

When are we supposed to use a bond enthalpy or mean bond enthalpy? What is the difference between the two?
by Edris Saadat 1A
Tue Jan 19, 2016 4:32 pm
Forum: Phase Changes & Related Calculations
Topic: Quiz 1 Prep Winter 2014 #4
Replies: 2
Views: 455

Quiz 1 Prep Winter 2014 #4

Consider the following numbered processes:

1) 2A+B ->3C+E

2) 2B ->A+D+E

3) E ->3B+C

How would I find H for 2A+D ->C? I dont know where I am supposed to start on this problem.
by Edris Saadat 1A
Sun Jan 10, 2016 5:35 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Molar heat capacity
Replies: 1
Views: 274

Molar heat capacity

Can someone clarify the difference between the molar heat capacity of a gas at constant volume and a gas at constant pressure?
by Edris Saadat 1A
Tue Dec 01, 2015 10:23 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7951
Views: 1212546

Re: Chemistry Jokes

What do you call cheese infused in sodium bicarbonate?

NaCHO3 Cheese
by Edris Saadat 1A
Sat Nov 28, 2015 12:41 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Naming shape of compounds
Replies: 2
Views: 523

Naming shape of compounds

How would you name the shape of [Fe(dien)2]2+? Other than drawing it out, how would we determine the shape?
by Edris Saadat 1A
Sun Nov 22, 2015 8:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Midterm question 4B
Replies: 2
Views: 381

Re: Midterm question 4B

I did not realize the solutions were posted online, thank you!
by Edris Saadat 1A
Sun Nov 22, 2015 6:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Midterm question 4B
Replies: 2
Views: 381

Midterm question 4B

Can someone explain why each shape has the shape that it does from this years midterm?
by Edris Saadat 1A
Sun Nov 22, 2015 6:09 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Base Strength
Replies: 1
Views: 546

Base Strength

How would you place bases in order of strength? From question 12.42, it asks: Place the following bases in order of increasing strength CN-, (C2H5)3N, N2H4, BrO-. Is there a trend in how you determine strength?
by Edris Saadat 1A
Wed Nov 18, 2015 10:32 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressures and Equilibrium
Replies: 2
Views: 418

Partial Pressures and Equilibrium

From question 10 of the fall 2013 prep quiz: Bromine chloride, bromine, and chlorine gases have reached equilibrium in a container at 500K according to the rxn, 2BrCl(g)<->Br 2 (g)+Cl 2 (g). Equilibrium partial pressures are 1.08 bar(BrCl), 4.9 bar(Br 2 ), and 7.6 bar(Cl 2 ). Half of the BrCl is rem...
by Edris Saadat 1A
Thu Nov 12, 2015 8:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium constants for different reactions
Replies: 1
Views: 234

Equilibrium constants for different reactions

From quiz 3 prep 3013 question 8: If the equilibrium constant for the rxn Ni(s)+4CO(g) -> Ni(CO) 4 (g) is 2.72 at a certain temperature, what is the equilibrium constant for the following rxn at the same temperature? Ni(CO) 4 (g) -> Ni(s)+4CO(g) I am confused on how exactly we are supposed to do the...
by Edris Saadat 1A
Tue Nov 03, 2015 3:12 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: HOMO and LUMO for molecules with 11 electrons
Replies: 1
Views: 284

HOMO and LUMO for molecules with 11 electrons

There isnt a specific example I have but just a general question about HOMO and LUMO for a molecules with 11 electrons. In this case, only Pi*px has an electron and Pi*py does not. The HOMO would be Pi*px, but what would the LUMO be? I was thinking its still Pi*py but Im not sure.
by Edris Saadat 1A
Sat Oct 31, 2015 4:46 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm 2011 question 6B
Replies: 2
Views: 777

Midterm 2011 question 6B

I am struggling with how exactly one should determine whether one compound is more ionic than the other. The question asks which compound is more ionic, then lists off compounds such as Chlorine Monoxide or Sodium Oxide, Antimony Trichloride or Indium Trichloride, Lithium Hydride or Hydrochloric aci...
by Edris Saadat 1A
Sun Oct 25, 2015 5:09 pm
Forum: Sigma & Pi Bonds
Topic: Valence electron configurations
Replies: 4
Views: 770

Re: Valence electron configurations

Im not sure. What about paramagnetic and diamagentic molecules, bond order, and the Molecular Orbital Theory?
by Edris Saadat 1A
Sun Oct 25, 2015 3:38 pm
Forum: Sigma & Pi Bonds
Topic: Valence electron configurations
Replies: 4
Views: 770

Valence electron configurations

On quiz 2 preparation(2014) questions 6 and 7 ask to find the valence electron configuration of molecular chlorine and He 2 . How exactly do we solve this? Must we do the lewis structure, find the correct shape, and then place sigma/pi bonds? Or do we place the sigma/pi bonds in their respective ene...
by Edris Saadat 1A
Thu Oct 22, 2015 11:35 am
Forum: Hybridization
Topic: Clarification on hybridization
Replies: 1
Views: 548

Clarification on hybridization

Im confused on how exactly we are supposed to find the hybridization of an atom. For example from the quiz 2 prep (2013), question 8 asks for the hybridization of the central atom of BeH 2 . Also, what are the hybrid orbitals in question 2? Where it asks for the hybrid orbitals used in the underline...
by Edris Saadat 1A
Sun Oct 11, 2015 4:03 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula of a hydrocarbon
Replies: 1
Views: 459

Empirical Formula of a hydrocarbon

On the preparatory quiz #1 from the workbook, I am having trouble on number 1 of the fall 2013 quiz. The question is "What is the empirical formula of a hydrocarbon which produces 2.703 g CO2 and 1.108 g H2O when combusted?" So far I have attempted to find the mass percentage of each atom ...
by Edris Saadat 1A
Sun Oct 11, 2015 3:52 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg problem
Replies: 2
Views: 347

Re: Heisenberg problem

I actually found this problem somewhere online trying to find extra practice problems.
by Edris Saadat 1A
Sat Oct 10, 2015 8:01 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg problem
Replies: 2
Views: 347

Heisenberg problem

Hello, I am having trouble with a Heisenberg equation problem. I dont know how to start this problem. Use the uncertainty principle to estimate the ground state energy of Hydrogen. I understand how to get the mass but I do not know how to get the velocity/position. Any help would be appreciated.

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