Search found 32 matches
- Fri Mar 11, 2016 10:24 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: What is A in the Arrhenius equation?
- Replies: 2
- Views: 620
What is A in the Arrhenius equation?
Do we just assume 1 or do we need to solve for it?
- 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: 977
Staggered vs eclipsed
Can someone clarify the differences between these two?
- Mon Feb 29, 2016 3:18 pm
- Forum: *Electrophilic Addition
- Topic: How many intermediates are there in electrophilic additions?
- Replies: 5
- Views: 1128
How many intermediates are there in electrophilic additions?
Is it always 1 intermediate or can there be more than one?
- Sun Feb 28, 2016 1:42 pm
- Forum: *Alkanes
- Topic: How to choose longest carbon chain?
- Replies: 1
- Views: 437
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?
- Sat Feb 27, 2016 12:25 pm
- Forum: *Alkenes
- Topic: Can we draw line structures in multiple ways?
- Replies: 2
- Views: 619
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.
- Thu Feb 25, 2016 6:38 pm
- Forum: *Alkanes
- Topic: Parenthesis around some carbons?
- Replies: 2
- Views: 1043
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?
CH3CH2C(CH3)2CCH
Why does the CH3 have parenthesis around it? Does it mean its a substituent or does it have no meaning?
- Tue Feb 23, 2016 1:53 pm
- Forum: Second Order Reactions
- Topic: Rate of reaction when given total time
- Replies: 1
- Views: 433
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?"
"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?"
- Tue Feb 23, 2016 1:50 pm
- Forum: Second Order Reactions
- Topic: Overall rate constant
- Replies: 1
- Views: 3131
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 ...
- 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: 537
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?"
"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?"
- Mon Feb 15, 2016 1:08 pm
- Forum: First Order Reactions
- Topic: Initial Rate
- Replies: 1
- Views: 508
Initial Rate
When an initial rate doubles, do you always assume its a first order reaction?
- Mon Feb 08, 2016 4:51 pm
- Forum: Balancing Redox Reactions
- Topic: 2009 Mid term #7
- Replies: 1
- Views: 491
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?
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?
- 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: 523
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?
- Thu Feb 04, 2016 2:50 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Sign of entropy
- Replies: 1
- Views: 406
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...
- Sun Jan 24, 2016 6:20 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Higher molar heat capacity
- Replies: 1
- Views: 350
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?
- 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: 532
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?
- Tue Jan 19, 2016 4:32 pm
- Forum: Phase Changes & Related Calculations
- Topic: Quiz 1 Prep Winter 2014 #4
- Replies: 2
- Views: 757
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.
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.
- Sun Jan 10, 2016 5:35 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Molar heat capacity
- Replies: 1
- Views: 460
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?
- Tue Dec 01, 2015 10:23 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3657745
Re: Chemistry Jokes
What do you call cheese infused in sodium bicarbonate?
NaCHO3 Cheese
NaCHO3 Cheese
- Sat Nov 28, 2015 12:41 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Naming shape of compounds
- Replies: 2
- Views: 711
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?
- Sun Nov 22, 2015 8:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Midterm question 4B
- Replies: 2
- Views: 516
Re: Midterm question 4B
I did not realize the solutions were posted online, thank you!
- Sun Nov 22, 2015 6:14 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Midterm question 4B
- Replies: 2
- Views: 516
Midterm question 4B
Can someone explain why each shape has the shape that it does from this years midterm?
- Sun Nov 22, 2015 6:09 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: Base Strength
- Replies: 1
- Views: 728
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?
- Wed Nov 18, 2015 10:32 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Partial Pressures and Equilibrium
- Replies: 2
- Views: 687
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...
- Thu Nov 12, 2015 8:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium constants for different reactions
- Replies: 1
- Views: 374
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...
- 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: 494
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.
- Sat Oct 31, 2015 4:46 pm
- Forum: Ionic & Covalent Bonds
- Topic: Midterm 2011 question 6B
- Replies: 2
- Views: 1647
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...
- Sun Oct 25, 2015 5:09 pm
- Forum: Sigma & Pi Bonds
- Topic: Valence electron configurations
- Replies: 4
- Views: 1227
Re: Valence electron configurations
Im not sure. What about paramagnetic and diamagentic molecules, bond order, and the Molecular Orbital Theory?
- Sun Oct 25, 2015 3:38 pm
- Forum: Sigma & Pi Bonds
- Topic: Valence electron configurations
- Replies: 4
- Views: 1227
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...
- Thu Oct 22, 2015 11:35 am
- Forum: Hybridization
- Topic: Clarification on hybridization
- Replies: 1
- Views: 772
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...
- Sun Oct 11, 2015 4:03 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical Formula of a hydrocarbon
- Replies: 1
- Views: 623
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 ...
- Sun Oct 11, 2015 3:52 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg problem
- Replies: 2
- Views: 470
Re: Heisenberg problem
I actually found this problem somewhere online trying to find extra practice problems.
- Sat Oct 10, 2015 8:01 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg problem
- Replies: 2
- Views: 470
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.