## Search found 21 matches

Tue Mar 08, 2016 3:55 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Torsional strain (Eclipsed to gauche)
Replies: 2
Views: 453

### Re: Torsional strain (Eclipsed to gauche)

When I was looking at it, I think that the torsional strain causes for the CH3 to be eclipsed again after the gauche conformation (force, or torsional strain was applied after the molecule had reached gauche formation). Consequently, the torsional strain would make it eclipsed again. However, after ...
Sun Feb 28, 2016 8:06 pm
Forum: *Electrophiles
Topic: nucleophiles vs electrophiles
Replies: 2
Views: 489

### Re: nucleophiles vs electrophiles

I do not believe that it is necessary or even most efficient to simply memorize all of the electrophiles and nucleophiles presented in the course reader. Rather, it would be more beneficial in my opinion to know the definition behind each (Nucleophile wants to go to the positive stuff, Electrophile ...
Tue Feb 16, 2016 3:56 pm
Forum: Second Order Reactions
Topic: 15.35
Replies: 1
Views: 333

### Re: 15.35

Essentially in this problem you are manipulating the equations to achieve your answer. First you start with the half life reaction where T1/2 = 1/k[A]o. From there you would solve for k to obtain the rate constant so that you can employ it in the second order reaction equation. The part where you mi...
Tue Feb 16, 2016 3:48 pm
Forum: General Rate Laws
Replies: 2
Views: 468

Hello! I have a general equation about how to perform a half life calculation. If we were given a table where we were given original concentration of a molecule [A], but were asked to convert the data into 1/[A] (second order reaction), would you use the [A] initial concentration or the 1/[A] concen...
Sun Feb 07, 2016 3:09 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Question about 14.55 (cathode/anode rxn)
Replies: 1
Views: 587

### Question about 14.55 (cathode/anode rxn)

Hello, The question reads: A 1.0M NiSO4 (aq) solution was electrolyzed by using inert electrodes. Write (a) the cathode reaction; (b) the anode reaction I know that for the cathode reaction it would involve the Ni molecule ( Ni2+ + 2e --> Ni) However, I am not understanding why the anode reaction in...
Thu Feb 04, 2016 1:42 pm
Forum: Balancing Redox Reactions
Topic: Question about 14.11 part D
Replies: 1
Views: 169

### Re: Question about 14.11 part D

I was looking through past posts, and read that in cell notations, the left side is always the anode and the right side will always be the cathode. Is this why the right side of the cell notation is flipped? Is this always the case?
Thu Feb 04, 2016 1:38 pm
Forum: Balancing Redox Reactions
Topic: Question about 14.11 part D
Replies: 1
Views: 169

### Question about 14.11 part D

Hello the question reads: Write the half reactions and balanced equation for the cell reaction for the following galvanic cell: Pt(s) | O2(g) | H+(aq) || OH-(aq) | O2(g) | Pt(s) My first question is would we have been given a table of half reactions on the midterm to choose the correct half reaction...
Sun Jan 31, 2016 8:23 pm
Forum: Balancing Redox Reactions
Topic: Balancing Redox Reactions
Replies: 2
Views: 446

### Re: Balancing Redox Reactions

I believe the oxidation state of ozone would be 0 since it is a tri-atomic form of oxygen. Since it is not paired with anything in specific, it would have an oxidation state of 0. Even though it is a very reactive substance I believe, since it is by itself and is not paired in a particular compound,...
Sun Jan 24, 2016 3:53 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Question on 8.65
Replies: 2
Views: 617

### Question on 8.65

The question states to calculate the standard enthalpy of formation of dinitrogen pentoxide from the following data, 2NO + O2 --> 2NO2 where deltaH = -114.1 kJ 4NO2 + O2 --> 2N2O5 where delta H = -110.2 kJ and from the standard enthalpy of formation of nitric oxide, NO (see appendix 2A) When I looke...
Sun Jan 17, 2016 11:28 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Clarification on First Law of Thermodynamics
Replies: 1
Views: 255

### Clarification on First Law of Thermodynamics

The first law of thermodynamics states that the internal energy of an isolated system will be constant. the equation is deltaU = q + w When looking at this equation, will the value of deltaU be 0 due to the fact that the internal energy has to be constant? Do the heat and work cancel out with each o...
Sun Jan 10, 2016 8:26 pm
Forum: Phase Changes & Related Calculations
Topic: Isolated systems
Replies: 3
Views: 484

### Re: Isolated systems

Yes the person above has a great answer to the question, and I would like to add a bit more just for memorization's sake. For a bomb calorimeter, you should always assume that it is an isolated system, because that is how the contraption is created. It does not want to release any heat and expose th...
Sun Dec 06, 2015 12:30 pm
Forum: Identifying Acidic & Basic Salts
Topic: Salt acidic or basic?
Replies: 3
Views: 2066

### Re: Salt acidic or basic?

Yes the person above has the correct idea! I can offer an example to further clarify the details as well. So say that you react CH3COOH with NaOH to form Na+CH3OO- and water. The salt in this case would be Na+CH3OO- where CH3COO- would be the conjugate base of the acid. Now look when the salt dissoc...
Sun Dec 06, 2015 12:25 pm
Forum: *Titrations & Titration Calculations
Topic: pH Sig figs
Replies: 2
Views: 551

### Re: pH Sig figs

When my TA was explaining the concept of sig figs in regards to pH she said that you would begin counting the sig figs after the decimal point. So say that you have a pH = 2.37, you would have two significant figures in the answer because you begin counting after the decimal. I hope this helped!
Thu Dec 03, 2015 9:47 pm
Forum: Calculating the pH of Salt Solutions
Topic: 2010 Final Q7B neutralization reaction
Replies: 2
Views: 619

### Re: 2010 Final Q7B neutralization reaction

As the person above said, a neutralization reaction is basically just a fancy way of saying a reaction between an acid and base to make a salt and water. You should know that a neutralization reaction will always make water, so that is a good indicator to see if something is a neutralization reactio...
Sat Nov 28, 2015 7:32 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Question about Buffers and Use of a Salt
Replies: 4
Views: 678

### Question about Buffers and Use of a Salt

Hello! When talking about buffers, I noticed that the usage of a salt was employed for the weak acid (conjugate base in form of salt), and for the weak base (conjugate acid in form of salt). Is the salt employed because it does not drastically fluctuate the pH, and you want to get the pH of the solu...
Tue Nov 17, 2015 4:45 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Question regarding significant figures in equilibrium calc.
Replies: 1
Views: 407

### Question regarding significant figures in equilibrium calc.

Hello! In the last Quiz 3 preparation quizzes, question 6 provides the equilibrium constant as 2.1 x 10^-3 but also gives the concentration of initial I2 to be 3.18 x 10^-4. I was wondering whether the final answer would retain the same amount of significant figures as the equilibrium constant (beca...
Sun Nov 01, 2015 8:52 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Question behind Molecular Orbital Theory
Replies: 1
Views: 248

### Question behind Molecular Orbital Theory

Hello! I was just wondering if there was a molecule like N2- if you would use the modified molecular orbital diagram that Lavelle used for z < 8. Since there is an extra electron, would you have to use the z > or equal to 8 one? I am thinking that since only an electron is added and the nuclear char...
Sun Oct 25, 2015 11:02 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability vs Increasing Polarizing Power
Replies: 1
Views: 749

### Polarizability vs Increasing Polarizing Power

Hello Community!

I am wondering what the difference is between polarizability and increasing polarizing power. I saw that they had opposite trends and was a bit confused on how that worked. What are the fundamental differences between the two?

Thank you!
Tue Oct 13, 2015 4:00 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Principle Quantum Level
Replies: 5
Views: 962

### Re: Principle Quantum Level

Hello!

@Chem_Mod , I believe that you said that DeltaE is equal to the Energy Initial - Energy Final. However, in the course reader, I saw that the Delta Energy was equal to Energy Final - Energy Initial.

I am a bit confused on this part, would you mind clarifying?

Thank you!!!
Sun Oct 11, 2015 11:20 pm
Forum: Trends in The Periodic Table
Topic: Electronegativity vs Electron Affinity
Replies: 1
Views: 448

### Electronegativity vs Electron Affinity

Hello! I was wondering what the significant differences were between electronegativity and electron affinity. I think they follow the same general trend of increasing to the right of the period and up a column. However, I do not know what the difference is between the two terms and get mixed up. Ele...
Sun Oct 04, 2015 1:09 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Confused on Problem 1.57 (regarding the Balmer Series)
Replies: 9
Views: 2344

### Confused on Problem 1.57 (regarding the Balmer Series)

Hello! The question reads "Lines in the Balmer series of the hydrogen spectrum are observed at 656.3, 486.1, 434.0, and 410.2 nm. What is the wavelength of the next line in the series?" ^^^ I have tried using Professor Lavelle's method from his Course Reader where En = -hR/n , but cannot s...