Search found 27 matches

by ssendhil
Thu Mar 10, 2016 10:06 am
Forum: Van't Hoff Equation
Topic: Finding Entropy using Van't Hoff Eq
Replies: 1
Views: 598

Finding Entropy using Van't Hoff Eq

Question 11.82 asks: 1.1 mMol of SO2 + 2.2 mMol O2 gas in 250 mL container. It's heated to 500 K and allowed to reach equilibrium. Which way will the equilibrium shift if it is then cooled to 298 K. By manipulating the variables in the Van't Hoff Equation we can find the standard H and tell which wa...
by ssendhil
Mon Mar 07, 2016 11:13 pm
Forum: *Calculations Using ΔG° = -RT ln K
Topic: Anti/Gauche Equilibrium Constants
Replies: 1
Views: 690

Anti/Gauche Equilibrium Constants

Self Test 3.3B on page 109 of the Organic book asks "Do you expect the equilibrium constant for 1-iodobutane to be larger or smaller for the gauche, anti inter-conversion? Explain.

What is the answer?
by ssendhil
Sun Mar 06, 2016 8:07 pm
Forum: *Ethers
Topic: Ether/Ester mix up
Replies: 1
Views: 636

Ether/Ester mix up

In the the Ether section of the organic book it says "as a result of limited hydrogen bonding ability, esters are less soluble in water than acohols ans carboxylic acids with similar molar masses" do they mean ether instead of ester? Same with this: "Esters are unable to form intermol...
by ssendhil
Sat Mar 05, 2016 9:16 pm
Forum: *Alkanes
Topic: Naming is Confusing
Replies: 1
Views: 326

Naming is Confusing

When naming organic compounds, when does atomic number get priority over alphabetical order naming? Thanks.
by ssendhil
Mon Feb 29, 2016 10:24 pm
Forum: *Electrophiles
Topic: Memory Tips
Replies: 8
Views: 1203

Re: Memory Tips

For me this is where the whip and nae nae come into play. Not necessarily the whip but NAE helps me remember N-ucleophiles A-ttack E-lectrophiles. Hope this helps.
by ssendhil
Sun Feb 28, 2016 2:29 pm
Forum: *Cycloalkenes
Topic: Naming Priorities (Organic Book 1.21 part B)
Replies: 1
Views: 371

Naming Priorities (Organic Book 1.21 part B)

If we use naming priorities for the second part I believe we should get: 1,6-dimethylcyclohexa-1,3-diene but the answer in the book is: 1,2-dimethylcyclohexa-1,4-diene The book's answer seems to prioritize the methyls over the double bonds which I thought we were not supposed to do. If anyone could ...
by ssendhil
Wed Feb 24, 2016 2:02 am
Forum: *Alkenes
Topic: Functional groups
Replies: 1
Views: 346

Functional groups

When naming alkenes or alkanes or alkynes are functional groups given priorities to the bonds?
by ssendhil
Mon Feb 15, 2016 3:35 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Unique Rxn Rate
Replies: 1
Views: 514

Unique Rxn Rate

Question 15.3c asks about the unique reaction rate but what does it mean to have a unique rate?
by ssendhil
Tue Feb 09, 2016 5:22 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Standard cell potential vs cell potential
Replies: 3
Views: 781

Re: Standard cell potential vs cell potential

When we find the half reactions and add the E knot values we get E knot of the cell. E values are usually given by the problem for the purposes of calculating Q (or concentrations) in the formula E= E,knot - (RT/nF)•lnQ . Usually if they do not give you the E value then they give you enough informat...
by ssendhil
Sun Feb 07, 2016 2:37 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Interpreting Cell Notation (Ch14 Q 15c)
Replies: 1
Views: 1411

Interpreting Cell Notation (Ch14 Q 15c)

The answer for this question is: Cd(s) | Cd(OH)2 | KOH || Ni(OH)3 | Ni(OH)2 | Ni(s) But I have a few questions: 1. How do you know when to use something like Pt(s) as the anode? 2. How do you know when to use something like Pt(s) as the cathode? 3. Can I replace Cd(s) with Pt(s) if I wanted to? 4. W...
by ssendhil
Mon Feb 01, 2016 12:04 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8205
Views: 1433345


People asked me if I rushed this quarter but the only thing I rushed was that last quiz.
by ssendhil
Tue Jan 26, 2016 1:52 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy Units
Replies: 2
Views: 478

Entropy Units

Are entropy units interchangable? Meaning are 15 J/ mol•K = 15 J/ g•Celcius?
by ssendhil
Mon Jan 25, 2016 12:37 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Isothermal and Reversible Processes
Replies: 1
Views: 313

Isothermal and Reversible Processes

Should we always assume that isothermal implies reversible? I believe in the book they make the assumption sometimes unless otherwise stated.
by ssendhil
Mon Jan 18, 2016 5:05 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Enthalpy of Formation Error
Replies: 1
Views: 512

Enthalpy of Formation Error

It appears that 8.59 from the book uses the Enthalpy of formation of H3O+ instead of H2O(l). Was I supposed to use the enthalpy of H3O+? The equation was 4HNO3(l) + 5N2H4(l) => 7N2(g) + 12H2O(l) .
by ssendhil
Mon Jan 18, 2016 3:41 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Heat Release Quantities
Replies: 1
Views: 311

Heat Release Quantities

In Question 8.51 of the Homework, the end value of for the Heat(rxn) is +23.9 * 10^3KJ but I calculated -23.9*10^3. The heat is being released and the answer key specifies this in italics but I don't understand why they make the value positive if they indicate that heat is being released.
by ssendhil
Mon Jan 11, 2016 10:33 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Positive/Negative Energy Values
Replies: 1
Views: 494

Positive/Negative Energy Values

Are Joules or KiloJoules the SI unit for energy? Also is the energy quantity positive or negative when heat is "absorbed" (when breaking a bond).
by ssendhil
Wed Jan 06, 2016 11:10 am
Forum: Phase Changes & Related Calculations
Topic: Vaporization Heat Transfer
Replies: 3
Views: 680

Vaporization Heat Transfer

Is Vaporization an endothermic or exothermic process?
by ssendhil
Sat Dec 05, 2015 12:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Doubling/Tripling/Quadrupling [ ] and finding their new Q
Replies: 1
Views: 349

Doubling/Tripling/Quadrupling [ ] and finding their new Q

On the third quiz, there was a question that asked what happens if you double the [ ] of both reactants and quadruple the [ ] of the products. If you do this with respect to Q, the concentrations would cancel out and there would be no change from the initial Q that was calculated. But, suppose that ...
by ssendhil
Mon Nov 23, 2015 11:09 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Square Planar Shape
Replies: 2
Views: 572

Square Planar Shape

How do you know whether or not the shape is square planar or tetrahedral when there are 4 ligand bonding sites to one Transition Metal?
by ssendhil
Mon Nov 16, 2015 10:39 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating Partial Pressure
Replies: 1
Views: 498

Calculating Partial Pressure

Question: Bromin chloride, bromine, and chlorine gases have reached equilibrium in a container at 500K according to the reaction 2BrCl (g) <-> Br2 (g) + Cl2 (g). Equilibrium partial pressures are 1.08 bar BrCl, 4.9 bar Br2, and 7.6 bar Cl2. Half the BrCl is removed from the container and equilibrium...
by ssendhil
Fri Nov 13, 2015 12:05 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Full M.O. Diagram
Replies: 1
Views: 333

Full M.O. Diagram

When I give the full M.O. Diagram why is it that the 1s added to the formula for Bond Order is the same as when I calculate the bond order for just the valence diagram? Logically it should be the same but I have trouble understanding how it works.
by ssendhil
Tue Nov 03, 2015 1:14 pm
Forum: Octet Exceptions
Topic: SO2 Best Lewis Structure
Replies: 2
Views: 2691

SO2 Best Lewis Structure

In the course reader Midterm Fall 2012, one of the questions asks us to draw the structure for SO2 and asks questions based of that structure. The answer key uses a lewis model that is not the best in terms of lowest formal charge. In my answer, I used the "best" one (two double bonds) rat...
by ssendhil
Sun Nov 01, 2015 7:24 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: (2013) Practice Quiz#2 Problem #10
Replies: 1
Views: 529

Re: (2013) Practice Quiz#2 Problem #10

For that part, the question is just asking whether the molecule is paramagnetic or diamagnetic. If the molecule has unpaired electorns, then it is paramagnetic and if it has no unpaired electorns then it is diamagnetic. O2 has two unpaired electrons as seen from its MO diagram, so it is paramagnetic.
by ssendhil
Fri Oct 23, 2015 10:14 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Order of orbitals
Replies: 1
Views: 381

Order of orbitals

When writing the ground state of an element is it wrong to order something as 4s2, 3d10 instead of 3d10, 4s2? I know 4s2 is filled in first but the answers to problems always seem to have them switched.
by ssendhil
Tue Oct 13, 2015 12:43 am
Forum: Significant Figures
Topic: Sig Figs in Quantum Questions
Replies: 2
Views: 574

Sig Figs in Quantum Questions

Hi everyone, I recently encountered a problem that gave the orbital n values for an electron and asked to find the wavelength. Because the only values given in the question were n=4 and n=5, how do I know how many sig figs to use for my answer?
by ssendhil
Thu Oct 08, 2015 11:30 pm
Forum: Einstein Equation
Topic: Wavelength/Frequency/Energy
Replies: 1
Views: 477


One of the questions in the book asked if energy would decrease if the frequency decreases. I said yes, but the answer key said no. I asked my TA and she agreed. Possible answer key error?
by ssendhil
Thu Oct 01, 2015 9:15 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Finding number of atoms, formula units and moles
Replies: 4
Views: 21198

Re: Finding number of atoms, formula units and moles

In regards to writing the formula, we know that magnesium has a charge of 1+ and sulfate, SO4, has a charge of 1-. Sulfate is a polyatomic ion so the charge of the whole thing is (SO4)1-. When you combine them you end up with MgSO4 and the "heptahydrate" is seven water molecules. ("He...

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