## Search found 20 matches

Tue Mar 15, 2016 6:54 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Predicting the sign of S Without Math
Replies: 2
Views: 1191

### Re: Predicting the sign of S Without Math

Since the moles of gas goes from 3 to 2, doesn't the entropy decrease?
Wed Feb 24, 2016 11:04 pm
Forum: *Cycloalkanes
Topic: Ring Substituents
Replies: 1
Views: 414

### Re: Ring Substituents

Yes, it is possible for a cyclic structure to have another cyclic structure as a substituent. An example of this is cyclopentylcyclodecane, whose line structure looks like this: http://chemwiki.ucdavis.edu/@api/deki/files/1885/=drawing4.gif?revision=1&size=bestfit&width=155&height=84"onc...
Wed Feb 24, 2016 10:51 pm
Forum: *Alkanes
Topic: Drawing Structures
Replies: 4
Views: 417

### Re: Drawing Structures

Are you referring to the number we put in front of the substituent? If you are, you always want the number to be as low as possible. So, if numbering from the right of the molecule gives the number 5 for the substituent while numbering from the left gives the number 3 for the substituent, you should...
Thu Feb 18, 2016 5:11 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Determining slow v fast reaction?
Replies: 3
Views: 3294

### Re: Determining slow v fast reaction?

In the textbook problems, it already states which reactions are fast and which reactions are slow. The quiz will most likely give that information as well!
Sun Feb 14, 2016 10:09 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Calculating Cell Potential
Replies: 3
Views: 994

### Re: Calculating Cell Potential

As you mentioned, there are two ways to approach this calculation. The two ways are: 1. We can add together the cell potential of the oxidation half-reaction and the cell potential of the reduction half-reaction. Since the cell potentials given to us on the cheat sheets are always in the form of a r...
Fri Feb 05, 2016 8:27 am
Forum: Administrative Questions and Class Announcements
Topic: Workbook
Replies: 1
Views: 352

### Re: Workbook

The workbook is supposed to be turned in before every quiz we take (with the practice test filled in), so it's unlikely that you'll find a cheaper one that hasn't been written in already. I'm not sure if you can buy the workbook without the course reader, but they're sold at Course Reader Material (...
Mon Feb 01, 2016 11:05 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Internal energy
Replies: 1
Views: 337

### Re: Internal energy

When the temperature is constant (isothermal process)
Wed Jan 20, 2016 6:37 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Q vs. Enthalpy?
Replies: 1
Views: 308

### Re: Q vs. Enthalpy?

Heat is the transfer of energy, while enthalpy is basically a measure of how much energy a system contains. ΔH is the change in that amount of energy. ΔH is equal to heat (q) when either the volume or the pressure is constant.
Mon Jan 11, 2016 1:13 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Pistons
Replies: 1
Views: 252

### Re: Pistons

The dictionary definition for a piston is, "A solid cylinder or disk that fits snugly into a hollow cylinder and moves back and forth under the pressure of a fluid, as in many engines, or moves or compresses a fluid, as in a pump or compressor."
Mon Jan 11, 2016 1:08 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy and Entropy
Replies: 3
Views: 483

### Re: Enthalpy and Entropy

The first response on this website explained it really well for me: http://socratic.org/questions/what-is-the-difference-between-entropy-and-enthalpy"onclick="window.open(this.href);return false; Conceptually: "Enthralled- H, is the sum of internal energy of a system and the product of the pres...
Fri Nov 27, 2015 2:22 pm
Forum: Photoelectric Effect
Topic: Video- The Photoelectric Effect
Replies: 3
Views: 803

### Video- The Photoelectric Effect

This video goes over the conceptual and mathematical aspects of the photoelectric effect.
Thank you for watching!
(Made by Justine Aziz (1J), Marla Dimetrios (1K), and Marina Habib (1K)
Sat Nov 21, 2015 8:04 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Sig figs
Replies: 1
Views: 350

### Re: Sig figs

From what I've been told by TA's, we should never truncate the value until the very end.
Sat Nov 14, 2015 10:27 pm
Forum: Naming
Topic: Naming Coordination Compounds?
Replies: 2
Views: 619

### Re: Naming Coordination Compounds?

For most anionic ligands, we can get the name by taking the element (in this case bromine), removing the end of the word, and attaching "-ido" (bromido). In order to find the oxidation number of cobalt, we have to figure out the oxidation number of the rest of the compound: - NH3 has no ch...
Sat Nov 14, 2015 10:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Videos
Replies: 2
Views: 654

### Re: Chemistry Videos

I believe Dr. Lavelle mentioned that it will only make up for the participation points we missed
Sat Nov 14, 2015 9:57 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelating Ligands
Replies: 3
Views: 552

### Re: Chelating Ligands

If you draw out the structure of the formula that is given and see that a ring has been formed with the ligand in it, then there is a chelating ligand.
Sat Nov 14, 2015 9:51 pm
Forum: Ideal Gases
Topic: Decrease in volume
Replies: 1
Views: 407

### Decrease in volume

For the equation:
2HCl(g) + I(s) --> 2HI(g) + Cl2(g)

why does the number of moles of HCl increase when the volume in the container decreases?
Sat Oct 31, 2015 10:53 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: H2SiO
Replies: 1
Views: 3743

### Re: H2SiO

I am not sure what you mean by "H's and Br's" canceling out since Br is not in the molecule. But, the lewis structure for H2SiO has a trigonal planar shape with Si as the central atom. In order for a molecule with the trigonal planar shape to be non polar, all three of the surrounding elem...
Fri Oct 23, 2015 10:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 2
Views: 358

### Polarity

How do we determine if the lone pairs in a molecule cancel out to make the entire molecule non polar?
Fri Oct 09, 2015 9:16 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Quantum Numbers
Replies: 1
Views: 258

### Re: Quantum Numbers

For every orbital (s,p,d,f), there is an l value. So, in your example, 3d corresponds to l = 2. As stated in the course reader, ml=-l,...,l. So, if l = 2, ml = -2, -1, 0, 1, 2.
s --> l = 0
p --> l = 1
d --> l = 2
f --> l = 3