Search found 26 matches

by Katie Clark 3B
Fri Mar 11, 2016 8:09 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Determining n in nernst equation
Replies: 1
Views: 4196

Determining n in nernst equation

How do you determine what n is in the Nernst equation? For example, if you had the equation 2Cr3+ + 3HClO2 + 4H20 -> CrO72- + 3HClO + 8H+ , how would you determine what to use for n in the equation E= Estandard - (.05916V)/n logQ
by Katie Clark 3B
Mon Mar 07, 2016 9:29 pm
Forum: *Cyclopropanes and Cyclobutanes
Topic: Determining direction of axial and equatorial bonds
Replies: 1
Views: 368

Determining direction of axial and equatorial bonds

For the various conformations (butterfly, envelope, chair, and boat), how do you know which axial bonds are up or down? I know that it alternates which up and down and does the same for equatorial. I'm wondering where you should start the axial up. For example, on the envelope conformation, how do y...
by Katie Clark 3B
Sun Mar 06, 2016 1:46 pm
Forum: *Alcohols
Topic: Types of alcohols
Replies: 1
Views: 416

Types of alcohols

In problem 20 of chapter 2 in the organic chemistry textbook, they ask to draw 2-methyl-2-butanol and then name what type of alcohol it is. The answer given is tertiary alcohol? How do you know it is tertiary? How can you tell?
by Katie Clark 3B
Sun Feb 28, 2016 4:45 pm
Forum: *Alkanes
Topic: Sec- structure
Replies: 1
Views: 281

Sec- structure

Can someone describe the basic structure of a substituent with the common name prefix sec-? I was not able to copy down the different structures that the guest lecturer showed on her powerpoint with the sec- structures on it. Or could you tell me where I would find this information in the textbook?
by Katie Clark 3B
Fri Feb 19, 2016 4:41 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Sign for Standard Reduction Potentials
Replies: 1
Views: 403

Sign for Standard Reduction Potentials

I'm wondering when the sign of standard E changes. On question 8 on the midterm, the oxidation half reaction was Cd->Cd 2+ + 2e - . In the formula sheets we are given, the standard E=-0.40 V for Cd 2+ +2e - ->Cd. However, in the answer key, the standard E for the half reaction is 0.40 V. Why is this?
by Katie Clark 3B
Sat Feb 13, 2016 1:33 pm
Forum: General Rate Laws
Topic: How to solve for time, given k and concentrations
Replies: 1
Views: 336

How to solve for time, given k and concentrations

How do you solve for time given k and the concentrations. For example, in the Winter 2014 Quiz 2 Prep #9, the question is: A reaction has k=8.39 M-1s-1. How long does it take for the reactant concentration to drop from 0.0840 M to 0.0220 M?
by Katie Clark 3B
Sat Feb 06, 2016 3:53 pm
Forum: Balancing Redox Reactions
Topic: Potential difference vs. cell potential
Replies: 1
Views: 186

Potential difference vs. cell potential

Can someone explain what potential difference actually is? Not the formula, but the definition. And what is the difference between potential difference and cell potential?
by Katie Clark 3B
Sat Jan 30, 2016 5:19 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electromotive force
Replies: 1
Views: 371

Electromotive force

Can someone explain what the electromotive force is? And what is its relation to the maximum potential difference?
by Katie Clark 3B
Sat Jan 23, 2016 5:49 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: How to find enthalpy of rxn using enthalpies of formation?
Replies: 2
Views: 344

How to find enthalpy of rxn using enthalpies of formation?

On the homework problem 8.51, the reaction is 4C 7 H 5 N 3 O 6 +21O 2 -> 28CO 2 + 10H 2 O+6N 2 . It is also given that the enthalpy of formation for TNT is -67 kJ per mol. Can someone explain why the solutions manual only used the enthalpies of formation for TNT, H 2 O and CO 2 to find the enthalpy ...
by Katie Clark 3B
Thu Jan 21, 2016 5:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz #1
Replies: 3
Views: 480

Quiz #1

For quiz #1, what topics will be covered? More specifically which lectures will be covered on the quiz?
by Katie Clark 3B
Sat Jan 16, 2016 9:15 pm
Forum: Calculating Work of Expansion
Topic: Work equation
Replies: 2
Views: 585

Work equation

Why is there a negative in the work equation w=-PΔV?
by Katie Clark 3B
Fri Jan 08, 2016 5:35 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Different heat capacities
Replies: 1
Views: 313

Different heat capacities

What is the difference between heat capacity, specific heat capacity, and molar heat capacity?
by Katie Clark 3B
Sat Dec 05, 2015 9:40 pm
Forum: *Titrations & Titration Calculations
Topic: Find the final pH of the final solution in a titration
Replies: 1
Views: 466

Find the final pH of the final solution in a titration

I couldn't understand how to solve for the final pH of the final solution in a titration. For example, in problem 13.23, the question is, what is the pH of the final solution for the titration of 5.00 mL 0.010 M NaOH with 0.005 M HCl. In the problem, we also had to find the initial pH and the pH at ...
by Katie Clark 3B
Fri Dec 04, 2015 12:30 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Solving for x in Problem 12.59 a
Replies: 1
Views: 342

Solving for x in Problem 12.59 a

When calculating the pH and pOH of 0.057 M NH 3 , I am confused about an approximation that the solution manual made when solving for x in the K b equation. The chemical equation was NH 3(aq) +H 2 0 (l) =NH 4(aq) + +OH - (aq) . I did an ice box and had that K b =x 2 /...
by Katie Clark 3B
Sat Nov 28, 2015 5:37 pm
Forum: Lewis Acids & Bases
Topic: Lewis vs. bronsted
Replies: 1
Views: 336

Lewis vs. bronsted

Can someone explain the difference between the Lewis definition and Brosted definition for acids and bases?
by Katie Clark 3B
Thu Nov 19, 2015 11:25 am
Forum: Naming
Topic: Naming complexes
Replies: 3
Views: 398

Re: Naming complexes

So if there the complex only had one (en), would the name still contain bis- since (en) is polydentate?
by Katie Clark 3B
Wed Nov 18, 2015 11:52 pm
Forum: Naming
Topic: Writing chemical formulas
Replies: 1
Views: 580

Writing chemical formulas

For potassium tetracyanonickelate (II), could someone explain where you incorporate the oxidation number when writing the formula. The answers never include a charge on the coordination complex which confuses me since we often write the names of these complexes and they were given to us with a negat...
by Katie Clark 3B
Wed Nov 18, 2015 11:47 pm
Forum: Naming
Topic: Naming complexes
Replies: 3
Views: 398

Naming complexes

Can someone explain to me why the name of [Cr(en) 2 (H 2 O)Cl]Cl 2 is aquachlorobis(ethylenediamine)chromium (III) chloride. I understand all of it except the bis(ethylenediamine) part. I know that the bis- is there because ethylenediamine is bidentate. But what I don't understand is why there isn't...
by Katie Clark 3B
Tue Nov 17, 2015 10:38 pm
Forum: Naming
Topic: Naming Coordinate Compounds
Replies: 2
Views: 378

Re: Naming Coordinate Compounds

You put it in alphabetical order using the A in aqua.
by Katie Clark 3B
Sat Nov 14, 2015 12:57 pm
Forum: Naming
Topic: Determining if a ligand is polydentate
Replies: 1
Views: 227

Determining if a ligand is polydentate

Can someone explain to me how to determine if a ligand is polydentate just by looking at its molecular formula? I am not sure how to identify them unless I write out the lewis structure. For example, HN(CH2CH2NH2)2.
by Katie Clark 3B
Fri Nov 06, 2015 3:04 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Molecular Orbital Theory
Replies: 2
Views: 345

Re: Molecular Orbital Theory

Use the molecular orbital diagram for whichever atom has the lower atomic number. For example if you had CO, you would use the molecular orbital diagram for Z<8 since carbon has an atomic number less than 8.
by Katie Clark 3B
Fri Oct 30, 2015 9:45 pm
Forum: Ionic & Covalent Bonds
Topic: Dissociation energy
Replies: 1
Views: 261

Dissociation energy

Can someone explain how to determine which bond has a greater dissociation energy? For example, which has a greater dissociation energy, O-H or S-H?
by Katie Clark 3B
Fri Oct 23, 2015 6:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Confusion on Homework Problem 4.13 Part A
Replies: 1
Views: 222

Confusion on Homework Problem 4.13 Part A

I am confused as to why the shape of the molecule I 3 - is linear. I got the correct Lewis structure for the molecule. The central atom had five regions of electron density. Why then is the shape linear? Wouldn't the three lone pairs of electrons affect the shape? Could someone please explain this t...
by Katie Clark 3B
Thu Oct 15, 2015 6:35 pm
Forum: Photoelectric Effect
Topic: Question 10 on Quiz 1 Preparation Fall 2013 in the Workbook
Replies: 1
Views: 321

Question 10 on Quiz 1 Preparation Fall 2013 in the Workbook

I have reworked question 10 and still cannot get the correct answer. The question reads, "If molybdenum is irradiated with light of wavelength of 294 nm, what is the maximum possible kinetic energy of the emitted electrons?". I got the correct answer for the first part of the question, &qu...
by Katie Clark 3B
Fri Oct 09, 2015 4:23 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Chapter 1 #15 HW problem
Replies: 2
Views: 462

Re: Atomic Spectra Chapter 1 #15 HW problem

I solved for the frequency using the given wavelength. I then pugged that value and n=1 into the equation from the book: \nu =R(\frac{1}{n_{f}^{2}}-\frac{1}{n_{i}^{2}}) . I plugged in n=1 to the first n in the equation. I then solved for the second n and found it to be equal to 3. Hope this ...
by Katie Clark 3B
Thu Oct 01, 2015 4:17 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Confusion on Worked Example in Course Reader
Replies: 1
Views: 288

Confusion on Worked Example in Course Reader

I have the Fall 2015 course reader for Chem 14A with Lavelle. On page 46 there is a worked example. The question is: "Calculate the frequency of light emitted by a hydrogen atom when an electron makes a transition from the fourth to the second principal quantum level." I understand how the...

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