## Search found 29 matches

Sat Mar 12, 2016 10:01 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Strongest Oxidizing/Reducing Agents
Replies: 1
Views: 287

### Strongest Oxidizing/Reducing Agents

What is the rule for determining a strong oxidizing agent or a strong reducing agent? Thanks!
Fri Mar 11, 2016 12:50 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Cv and Cp
Replies: 4
Views: 696

### Re: Cv and Cp

If it does not specify, then use Cv! I saw a problem that didn't say anything about pressure, but temperature and volume changed. In the solution, you first calculate the change in entropy associated with the volume change, and then assuming constant volume, calculate the entropy change associated w...
Fri Mar 11, 2016 12:42 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy and Stability
Replies: 1
Views: 4988

### Gibbs Free Energy and Stability

In my notes I was reading that if dG is negative, then the compound is more stable and is dG is positive, then the compound is less stable. I am confused since a negative dG corresponds to spontaneity, and if a process is spontaneous, wouldnt it be less stable?
Thanks!
Thu Mar 10, 2016 10:36 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Cv and Cp
Replies: 4
Views: 696

### Re: Cv and Cp

For that equation you use specific heat capacity. For instance, water's specific heat capacity is 4.184J/g(C). Cv and Cp only apply to monatomic ideal gases. Cv is 3/2R while Cp is 5/2R. Hope that helps!
Wed Mar 02, 2016 9:31 pm
Replies: 2
Views: 384

### Re: Electrophilic Addition and Intermediates

Wouldn't there be only one intermediate since in the reaction profile graph there is only one dip because it is only a two step reaction?
Wed Mar 02, 2016 6:55 pm
Forum: *Alkanes
Topic: Halogen Numbering
Replies: 1
Views: 315

### Halogen Numbering

When deciding how to number multiple halogens on an alkane, (for instance bromo and iodo) which halogen should get the lower number? Is the numbering of halogens based on alphabetical order or another factor such as electronegativity? Thanks!
Thu Feb 25, 2016 12:18 pm
Forum: *Alkanes
Topic: Tert-butyl vs. Neopentyl
Replies: 1
Views: 714

### Tert-butyl vs. Neopentyl

Tert-butyl and Neo-pentyl look almost identical when connected to a compound. How can we tell the difference in between the two? Thanks!
Wed Feb 17, 2016 8:50 pm
Forum: General Rate Laws
Topic: Pseudo Rate Law
Replies: 2
Views: 1269

### Pseudo Rate Law

In class, we went over pseudo first order and pseudo second order reactions. I dont really understand what these are for or why they are important. Could someone please explain? Thanks!
Tue Feb 09, 2016 10:27 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Midterm 2013 #7
Replies: 3
Views: 550

### Re: Midterm 2013 #7

If you use the equation Ecathode - Eanode, you dont flip the sign of the anode, you leave it positive. If you flip the sign of the anode, then you should add the two cell potentials.
Tue Feb 09, 2016 10:11 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Mercury as an Electrode
Replies: 1
Views: 253

### Mercury as an Electrode

Can liquid mercury act as an electrode? I have seen some instances where mercury is used as an electrode, but how is that possible if it is in a liquid state? Thanks!
Thu Feb 04, 2016 11:55 am
Forum: Balancing Redox Reactions
Topic: Oxidation Numbers for O2 and O3
Replies: 1
Views: 6295

### Oxidation Numbers for O2 and O3

Why is the oxidation number 0 for molecules in their natural forms, such as H2 gas or O2 gas? Also, what is the oxidation number of ozone? Thanks!
Tue Jan 26, 2016 9:42 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Balancing Equations
Replies: 1
Views: 321

### Balancing Equations

When balancing our equations for calculating standard molar entropy/enthalpy or Gibbs, should we be multiplying by whole numbers or fractions? For instance, #9 in Quiz 1 Winter 2014, I initially balanced the reaction HgO ---> Hg + O2 by multiplying O2 by (1/2). When I did this, I got half of the val...
Sun Jan 24, 2016 3:18 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Rigidity and Entropy
Replies: 1
Views: 790

### Rigidity and Entropy

Upon doing homework problems, I find that many answers to which compound would have higher entropy is one that is less rigid. What determines rigidity of a compound and how is it measured? Also, what would play a bigger role in determining entropy, the number of atoms in the molecule or its rigidity...
Tue Jan 19, 2016 11:11 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Homework 8.27
Replies: 1
Views: 266

### Re: Homework 8.27

A reversible process is one that takes place when internal and external pressures are roughly equal and any infitesimally small change in pressure can reverse the process. Isothermal refers to the absence in change of temperature. An irreversible process refers to one that differs in external from i...
Wed Jan 13, 2016 11:06 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Constant Volume and Bomb Calorimeter
Replies: 1
Views: 419

### Constant Volume and Bomb Calorimeter

How is work done in a bomb calorimeter if technically no work is done at constant volume since work measures the change in volume times pressure?
Thu Jan 07, 2016 11:47 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Breaking/Forming Bonds to find Reaction Enthalpy
Replies: 1
Views: 260

### Re: Breaking/Forming Bonds to find Reaction Enthalpy

Both ways work equally. If you are unsure of which bonds form or break or which would cancel out, then it would be best to complete work for all bonds and add/subtract each separate bond enthalpy. It does help your understanding if you try the method which requires to only focus on the bonds that br...
Tue Dec 01, 2015 12:16 am
Forum: Biological Examples
Topic: Drawing Possible Structure of Dimercaprol
Replies: 1
Views: 727

### Drawing Possible Structure of Dimercaprol

On the past final exam question in 2014 number 4, students are asked to draw a possible structure of dimercaprol (2, 3-dimercapto-1-propanol) bound eto Hg2+. How do you know what the structure looks like? What is the importance of the numbers in (2, 3-dimercapto-1-proponal)? Also, why does the struc...
Wed Nov 25, 2015 5:15 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Using the formula
Replies: 2
Views: 671

### Re: Using the formula

The other variables, Ka and Kb represent acidity and basicity constants. Ka is the acid ionization constant and represents equilibrium for reactions of weak acids. Kb is the base ionization constant and represent equilibrium for reactions of weak bases. The Ka and Kb values for many weak acids and b...
Tue Nov 17, 2015 10:00 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Fall 2009 Quiz 3 Prep #9
Replies: 3
Views: 590

### Re: Fall 2009 Quiz 3 Prep #9

I think for increasing concentration you look at the coefficients as the number of moles for the gases. Since there is only one mole of gas on the left and two on the right, increasing concentration would cause a shift to the left, where less moles of gas are present.
Tue Nov 17, 2015 9:54 pm
Forum: Naming
Topic: -ide ending on anions
Replies: 1
Views: 394

### Re: -ide ending on anions

The cl2 molecule has a negative charge, so it is chloride. This is different than just a regular chlorine atom.
Tue Nov 17, 2015 9:48 pm
Forum: Naming
Topic: Naming for NO2-
Replies: 1
Views: 333

### Naming for NO2-

Would NO2- be nitro or nitrito? I have seen it both ways and was wondering which would be most correct. Thank you!
Wed Nov 11, 2015 10:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pg 53 green workbook #10, converting to atm
Replies: 1
Views: 358

### Re: pg 53 green workbook #10, converting to atm

You would convert the x by using the equation PV = nRT.
Wed Nov 11, 2015 10:03 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Shape of Coordination Compounds
Replies: 1
Views: 424

### Re: Shape of Coordination Compounds

For coordination compounds, the only shapes you will most likely see are tetrahedral, and octahedral. Square planar would probably not come up, but you can check by counting valence electrons and drawing out the structure. The book differentiates square planar from tetrahedral by describing tetrahed...
Wed Oct 28, 2015 4:27 pm
Forum: Electronegativity
Topic: electronegativity and formal charge
Replies: 1
Views: 1297

### Re: electronegativity and formal charge

The more desirable resonance structures are those which there is no formal charge on the central atom. Thus, the resonance structure was not included in the answer because the other four would contribute more to the hybrid. And you are completely right about the nitrogen possessing the single electr...
Wed Oct 21, 2015 11:05 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Homework 4.23 C
Replies: 1
Views: 703

### Homework 4.23 C

When I drew the shape of IO2F2-, I drew it with Iodine double bonded to one of the Oxygen atoms with a lone pair, resulting in a formal charge of zero. However, in the answer book, the Iodine atom is single bonded to all atoms in the molecule and Iodine does not have a formal charge of zero. Which s...
Tue Oct 13, 2015 2:43 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Outer shell of Cr 2+
Replies: 1
Views: 456

### Re: Outer shell of Cr 2+

Chromium is one of those exceptions where the d orbital is filled before the s orbital. Since the valence electron configuration for chromium is 3d5 4s1, taking away two electrons will result in the same valence electron configuration as titanium, which has 3d2 4s2, which adds up to 4 valence electr...
Thu Oct 08, 2015 3:03 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Applied Wavefunction
Replies: 1
Views: 323

### Re: Applied Wavefunction

The trough of the wave function is called a node, where the probability density, or probability of finding an electron is zero.
Thu Oct 01, 2015 10:23 pm
Forum: Balancing Chemical Reactions
Topic: Writing an Equation for the Reaction
Replies: 9
Views: 2460

### Re: Writing an Equation for the Reaction

When an element or molecule combusts, you must add O2 gas.
Thu Oct 01, 2015 10:21 pm
Forum: Balancing Chemical Reactions
Topic: Clarifying the State of the Reactants and Products
Replies: 4
Views: 758

### Re: Clarifying the State of the Reactants and Products

It is important to write the clarification of the element's state on every equation. It demonstrates how the molecules undergo chemical and physical change, such as when a precipitate forms. Most professors mark down when equations lack the clarifications.