## Search found 14 matches

Mon Feb 09, 2015 10:25 pm
Forum: General Science Questions
Topic: Sigfigs for temperature
Replies: 1
Views: 925

### Sigfigs for temperature

Question 3A for the 14B Midterm 2014 is as follows: Charmander is battling Squirtle in an epic Pokemon battle! Squirtle has a protective outer shell with a heat capacity of 500. x 10^6 kJ/C. For Charmander to deal a critical hit to Squirtle, the temperature of Squirtle's shell must attain a temperat...
Tue Feb 03, 2015 6:48 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Concentration and direction of reaction
Replies: 2
Views: 590

### Concentration and direction of reaction

Question 99 asks that a) If you were to construct a concentration cell in which one half-cell contains 1.0 M CrCl3 and the other half-cell 0.0010 M CrCl3, and both electrodes were chromium, at which electrode would reduction spontaneously take place? This would be the side with the highest concentra...
Sun Feb 01, 2015 6:55 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Which half-reaction to use?
Replies: 1
Views: 355

### Which half-reaction to use?

Problem 17 asks to write the balanced half-reactions for the redox reaction of an acidified solution of potassium permanganate and iron(II) chloride. I found out the half-reaction of permanganate in the standard potential chart at the back of the book, MnO4 + 8H+ 5e- -> Mn2+ + 4H2O (E = 1.51) becaus...
Wed Jan 21, 2015 11:28 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Which value of R? Question 105
Replies: 2
Views: 1506

### Which value of R? Question 105

Part a) asks to calculate the work that must be done against the atmosphere for the expansion of the gaseous products in the combustion of 1.00 mol C6H6 (l) at 25C and 1.00 bar. If you write out the equation, you get C6H6+15/2 O2 -> 6CO2 + 3H20. To calculate work I used the ideal gas law so that w=-...
Sun Jan 11, 2015 4:14 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: What to use each value of R
Replies: 1
Views: 3497

### What to use each value of R

I'm confused on what values of the gas constant to use for different equations, particularly 8.314 J/Kmol and 8.206x10^-2 Latm/Kmol. What is the difference between them?
Thu Dec 11, 2014 11:18 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Bond order and ionization energy
Replies: 1
Views: 2030

### Bond order and ionization energy

For 4C in the 2011 exam, why does F2+ have the highest ionization energy? What is the relationship between ionization energy and bond order?
Tue Dec 09, 2014 7:14 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Buffer Solution Problem (12.22)
Replies: 1
Views: 400

### Buffer Solution Problem (12.22)

For part d, the question asks what volume of .200M K2CO2 must be added to 100mL of .100 M KHCO3 to prepare a buffer solution with a pH of 11.00. I know that the chemical reaction is HCO3- + H20 -> CO3 2- + H30 +, and that the ratio of concentrations of CO3 2- and HCO3 - is 5.6, but I can't seem to f...
Wed Nov 26, 2014 9:56 am
Forum: Bronsted Acids & Bases
Topic: Lewis structure of SO2?
Replies: 1
Views: 690

### Lewis structure of SO2?

Question 17 in the textbook asks to write the Lewis structure of each reactant, identify the Lewis acid and base, and then write the Lewis structure of the product. The reactants side given is Cl- + SO2. I know that Cl- is a Lewis base, which means that SO2 must be a Lewis acid because Cl- donates i...
Tue Nov 25, 2014 5:19 pm
Forum: Bronsted Acids & Bases
Topic: J11 Question
Replies: 1
Views: 413

### J11 Question

The question for J11 asks to write the chemical equation for the proton transfer reaction of the given cation/anion with water, provided that the anion/cation is a weak acid/base. The compounds given are NaC 6 H 5 O, KClO, C 5 H 5 NHCl, and NH 4 Br. The equation for the first question was NaC 6 H 5 ...
Mon Nov 03, 2014 10:36 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Atom arrangement of CH2Cl2
Replies: 1
Views: 2191

### Atom arrangement of CH2Cl2

When predicting whether or not CH2Cl2 is polar or nonpolar, the atom arrangement is a Carbon atom in the middle with 2 Hydrogen and 2 Chlorine on the four sides. For example, in a Lewis structure diagram, a chlorine would be at the 12 o'clock position (or vice versa), with another chlorine at the 3 ...
Mon Nov 03, 2014 10:29 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angle length for CH3-
Replies: 1
Views: 9937

### Bond angle length for CH3-

For other molecules, for example IO3- and XeO3, which all contain a single lone pair, their electron configuration is tetrahedral and their molecular shape is trigonal pyramidal. Because the lone pair's electron are more diffuse, this causes the bond angles of these two molecules to be a bit less th...
Sun Oct 26, 2014 12:09 am
Forum: Octet Exceptions
Replies: 1
Views: 456

For the radical molecule ClO, why is Chlorine assigned seven valence electrons while oxygen is assigned eight? What dictates that this configuration is not the other way around?
Sat Oct 18, 2014 9:06 pm
Forum: Trends in The Periodic Table
Topic: Trends in Atomic and Ionic Radius
Replies: 2
Views: 546

### Trends in Atomic and Ionic Radius

(I had originally wanted to post a picture of the question, but I wasn't able to find the "upload attachment" button, so I'll describe it as best as I can.) (#129 in the textbook, page 54) The picture showed the reaction between a sodium and chlorine atom, with a large circle labeled 'A' a...
Sun Oct 12, 2014 4:48 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Online Module Atomic Spectoroscopy Question
Replies: 1
Views: 465

### Online Module Atomic Spectoroscopy Question

For the online module titled "Atomic Spectra and the Bohr Frequency Condition," there are two corresponding questions that ask what one line represents on an atomic absorption spectrum and what one line represents on an atomic emission spectrum. I narrowed down the two answer choices for b...