## Search found 16 matches

Thu Mar 16, 2017 8:47 pm
Forum: *Alkenes
Topic: Naming Convention for Double Bonds
Replies: 1
Views: 660

### Naming Convention for Double Bonds

When we name an organic molecule with a double bond, do we always have to identify where the double bond is located?
Wed Mar 08, 2017 10:47 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8017
Views: 1403314

### Re: Post All Chemistry Jokes Here Tue Feb 14, 2017 3:41 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Winter 2013 Midterm #7: Which Nernst Equation to Use?
Replies: 2
Views: 380

### Winter 2013 Midterm #7: Which Nernst Equation to Use?

#7 of the Winter 2013 practice midterm uses the Nernst equation E = E˚ - \frac{0.05916V}{n} logQ to solve for K. Why isn't the other equation E = E˚ - \frac{RT}{nF} lnQ used? When I used the second equation, the answer wasn't the same as when I used the first. How do you know when to use which equat...
Sat Feb 11, 2017 5:25 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Quiz One - #5 Calculating Heat
Replies: 2
Views: 351

### Re: Quiz One - #5 Calculating Heat

I think we have the same quiz--melting a -55˚C block of ice into 25˚C water? When you first melt ice from -55˚to 0˚, you use the specific heat capacity of ice in the equation q = mc∆T. During the phase change from ice to water (at 0˚), you use the heat of fusion in the equation q = n∆H fus (note tha...
Thu Jan 26, 2017 11:03 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Quiz 1 Prep Question 3
Replies: 4
Views: 689

### Re: Quiz 1 Prep Question 3

Since both pressure and volume are changing (implying constant temp), you would use the equation W = -nRT. For all reversible reactions, ∆U = 0. You can use these two equations to solve for w, q, and ∆U.
Wed Jan 25, 2017 12:12 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Molar Heat Capacity for Phase Change of Water
Replies: 1
Views: 297

### Molar Heat Capacity for Phase Change of Water

At constant pressure, why is Cp (s) > Cp (l) > Cp (g) for the phase change of water?
Mon Jan 16, 2017 12:09 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8017
Views: 1403314

### Re: Post All Chemistry Jokes Here

Organic chemistry is difficult. Those who study it have alkynes of trouble.
Sat Dec 03, 2016 7:49 pm
Forum: *Titrations & Titration Calculations
Topic: Weak Acid Titration Equilibrium Table Equation? [ENDORSED]
Replies: 1
Views: 603

### Weak Acid Titration Equilibrium Table Equation?[ENDORSED]

When you're trying to find the pH at the stoichiometric point of a titration of a weak acid and a strong base, why do you use the reaction between the salt and H 2 O as the chemical equation for the equilibrium table? Why don't you use the reaction between the weak acid and strong base? For example,...
Tue Nov 15, 2016 12:42 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Fall 2014 Quiz Prep #8
Replies: 1
Views: 313

### Re: Fall 2014 Quiz Prep #8

You don't need to use PV=nRT for this problem! :) Just use the ICE table Since you already set the equilibrium constant expression, I'm assuming you got: K p = P NH3 (P H2S ) = 0.11 Using the ICE table, you would ignore NH 4 HS (because it's a solid) and just focus on NH 3 & H 2 S Initial partia...
Sat Nov 12, 2016 2:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Clarification on R and P Calculations
Replies: 2
Views: 312

### Re: Clarification on R and P Calculations

The brackets indicate the molar concentrations of the R and P, not molar masses.
Kp measures equilibrium for gas pressures, so you use the partial pressures of R and P.

Solids and liquids aren't included in the equilibrium calculations because their molar concentrations don't change in a reaction.
Sat Nov 12, 2016 1:48 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: What is a Ligand?
Replies: 3
Views: 949

### What is a Ligand?

I'm not sure what exactly a ligand is. Is it just any atom attached to a central atom of a molecule? Or is a ligand specifically a transition metal, polyatomic ion, etc?

Thank you!
Tue Oct 25, 2016 12:22 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Workbook: Quiz 2 Prep #4
Replies: 3
Views: 499

### Workbook: Quiz 2 Prep #4

For the electron configuration of Cl - using noble gas abbreviation, should it be [Ne] 3s 2 3p 6 or simply [Ar]? My high school AP chem teacher taught me the first is the correct configuration and the second is not quite correct. Should the configuration be using [Ne] or are both correct? Thank you!
Fri Oct 21, 2016 4:09 pm
Forum: Lewis Structures
Topic: Lewis Structure regarding the angles
Replies: 2
Views: 403

### Re: Lewis Structure regarding the angles

In class, Dr. Lavelle used the example of BF 3 for a trigonal planar structure. For your case, let's say one of the F atoms is Cl. Since Cl is a bigger atom than F (thus more repulsion), it would cause the angle between the Cl and F atoms to become bigger. Knowing that the angle between atoms of a t...
Tue Oct 11, 2016 3:27 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Question about Uncertainty in Velocity [ENDORSED]
Replies: 1
Views: 356

### Question about Uncertainty in Velocity[ENDORSED]

When a problem says that ∆v is ± ____ m/s, why do you multiply the ∆v value by 2 when you're solving the uncertainty equation?
Mon Oct 10, 2016 4:09 pm
Forum: Photoelectric Effect
Topic: Ch. 1 HW #33c
Replies: 1
Views: 344

### Re: Ch. 1 HW #33c

The answer you found for part b, E = 1.66 x 10 -17 J, is the work function (threshold energy). In part c, you're trying to find the energy of the photon, which is: E photon = work function (threshold energy) + E k Plug in the answer from part b in to the the work function, and plug in the mass and v...
Sat Oct 01, 2016 11:23 am
Forum: Molarity, Solutions, Dilutions
Topic: Clarification for G.7
Replies: 2
Views: 426

### Clarification for G.7

You need to prepare 510. g of an aqueous solution containing 5.45% KNO3 by mass. Describe how you would prepare the solution and what mass of each component you would use. Is the question saying that there is 510. g of substance that is dissolved into solution? Or is 510. g of solution is measured o...