CHEMISTRY COMMUNITY

Edris Saadat 1A

Do we just assume 1 or do we need to solve for it?

Edris Saadat 1A

Can someone clarify the differences between these two?

Edris Saadat 1A

Is it always 1 intermediate or can there be more than one?

Edris Saadat 1A

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?

Edris Saadat 1A

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.

Edris Saadat 1A

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?

Edris Saadat 1A

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?"

Edris Saadat 1A

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 ...

Edris Saadat 1A

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?"

Edris Saadat 1A

When an initial rate doubles, do you always assume its a first order reaction?

Edris Saadat 1A

Balance the following redox rxn that occurs under acidic conditions.

Cr₂O₇^2-(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?

Edris Saadat 1A

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?

Edris Saadat 1A

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...

Edris Saadat 1A

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?

Edris Saadat 1A

When are we supposed to use a bond enthalpy or mean bond enthalpy? What is the difference between the two?

Edris Saadat 1A

Consider the following numbered processes:

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

2) 2B ->A+D+E

3) E ->3B+C

How would I find $\Delta$ H for 2A+D ->C? I dont know where I am supposed to start on this problem.

Edris Saadat 1A

Can someone clarify the difference between the molar heat capacity of a gas at constant volume and a gas at constant pressure?

Edris Saadat 1A

What do you call cheese infused in sodium bicarbonate?

NaCHO₃ Cheese

Edris Saadat 1A

How would you name the shape of [Fe(dien)2]²⁺? Other than drawing it out, how would we determine the shape?

Edris Saadat 1A

I did not realize the solutions were posted online, thank you!

Edris Saadat 1A

Can someone explain why each shape has the shape that it does from this years midterm?

Edris Saadat 1A

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?

Edris Saadat 1A

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...

Edris Saadat 1A

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...

Edris Saadat 1A

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.

Edris Saadat 1A

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...

Edris Saadat 1A

Im not sure. What about paramagnetic and diamagentic molecules, bond order, and the Molecular Orbital Theory?

Edris Saadat 1A

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...

Edris Saadat 1A

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...

Edris Saadat 1A

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 ...

Edris Saadat 1A

I actually found this problem somewhere online trying to find extra practice problems.

Edris Saadat 1A

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.

CHEMISTRY COMMUNITY

Search found 32 matches

What is A in the Arrhenius equation?

Staggered vs eclipsed

How many intermediates are there in electrophilic additions?

How to choose longest carbon chain?

Can we draw line structures in multiple ways?

Parenthesis around some carbons?

Rate of reaction when given total time

Overall rate constant

Effect of cell size and precipitation on potential

Initial Rate

2009 Mid term #7

Mid term 2011 #6

Sign of entropy

Higher molar heat capacity

Bond enthalpy vs mean bond enthalpy

Quiz 1 Prep Winter 2014 #4

Molar heat capacity

Re: Chemistry Jokes

Naming shape of compounds

Re: Midterm question 4B

Midterm question 4B

Base Strength

Partial Pressures and Equilibrium

Equilibrium constants for different reactions

HOMO and LUMO for molecules with 11 electrons

Midterm 2011 question 6B

Re: Valence electron configurations

Valence electron configurations

Clarification on hybridization

Empirical Formula of a hydrocarbon

Re: Heisenberg problem

Heisenberg problem