Search found 21 matches

Sun Mar 19, 2017 12:01 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: cell potential equations
Replies: 3
Views: 388

cell potential equations

For the equation E= E -RT/nF lnQ and E=E- 0.05916/n logQ, I get different answers. Is one preferred over the other? Or will both answers be accepted?
Sat Mar 18, 2017 11:59 pm
Forum: General Rate Laws
Topic: pre equilibrium
Replies: 4
Views: 634

pre equilibrium

Hi,
What is the general purpose of the pre equilibrium approach? When do we use it?

Thanks
Sat Mar 11, 2017 10:03 am
Topic: number of steps [ENDORSED]
Replies: 2
Views: 763

number of steps[ENDORSED]

Hi, so is electrophilic addition always 2 steps and SN2 reactions always 1 step?

Thanks
Sun Mar 05, 2017 12:01 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: rate determining and rate limiting step [ENDORSED]
Replies: 1
Views: 413

rate determining and rate limiting step[ENDORSED]

Hi,
Is the rate determining step (which is the slow step) the same as rate limiting step?

Thanks
Sun Feb 26, 2017 12:55 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: pre equilibrium approach
Replies: 2
Views: 391

pre equilibrium approach

When do we know to use the pre equilibrium approach?
Thanks
Sat Feb 18, 2017 11:59 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: First order, second order reactions [ENDORSED]
Replies: 6
Views: 984

First order, second order reactions[ENDORSED]

What is an easy way to remember how to determine if a reaction is first order or second order?
Thanks
Sun Feb 12, 2017 8:07 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy w/ Diagram
Replies: 2
Views: 453

Bond Enthalpy w/ Diagram

In a complex diagram of a reaction, how can you tell which bonds are broken and which are formed?
Sat Feb 04, 2017 8:45 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8034
Views: 1407983

Re: Post All Chemistry Jokes Here

Why are chemists great for solving problems?
A: They have all the solutions!
Fri Jan 27, 2017 8:04 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Vant Hoff Equation
Replies: 1
Views: 352

Vant Hoff Equation

In the course reader it says that ln (K2/k1)=delta H/RT2 + delta H/Rt1 and that we can assume that delta S is constant. Why can we assume that delta S is constant?
Fri Jan 20, 2017 7:13 pm
Forum: Phase Changes & Related Calculations
Topic: Q [ENDORSED]
Replies: 1
Views: 410

Q[ENDORSED]

From a problem, how can you tell whether to use q=mc delta t or q=nc delta t?

Thanks
Fri Jan 13, 2017 4:54 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: standard enthalpy
Replies: 1
Views: 281

standard enthalpy

In the course reader it says that when finding standard enthalpy, we have to make sure everything is in standard state. What does it mean by "standard state"? Can you give an example?
Thanks
Fri Dec 02, 2016 7:39 pm
Forum: Empirical & Molecular Formulas
Topic: mmol and mol
Replies: 1
Views: 639

mmol and mol

In a molecular formula problem, we are given the mg of each atom, and in the answers they do not convert it to g but leave it as mg, therefore using mmol. Is there a difference if we converted the mg to g and mmol to mol? Which is preferred?
Fri Nov 25, 2016 11:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Change of K [ENDORSED]
Replies: 1
Views: 284

Change of K[ENDORSED]

Why does change in temperature cause K value to change but not change in pressure or volume?
Thu Nov 17, 2016 7:08 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: NO +2 Orbital
Replies: 1
Views: 316

NO +2 Orbital

If I were to do a MO diagram for NO +2, would I take away 1 e- from O and 1 e- from N or would I take away 2 e- from just O?

Thanks
Sun Nov 13, 2016 3:22 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: e- configuration with pi & sigma bonds
Replies: 1
Views: 358

e- configuration with pi & sigma bonds

Is there a difference between (pi,2p)^4 and (pi,2px)^2(pi,2py)^2?

Thanks
Fri Nov 04, 2016 5:07 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Paramagnetic vs Diamagnetic
Replies: 2
Views: 367

Paramagnetic vs Diamagnetic

Is the only way to figure out if a material is paramagnetic or diamagnetic is to draw out the molecular orbital energy diagrams?

Thanks
Wed Oct 26, 2016 7:55 pm
Forum: Lewis Structures
Topic: "best" lewis structure
Replies: 3
Views: 547

"best" lewis structure

When drawing the "best" lewis structure, do the most electronegative atom always receive the charge in ionic bonds?

Thanks
Fri Oct 21, 2016 4:49 pm
Forum: Trends in The Periodic Table
Topic: Determining electro negativity
Replies: 1
Views: 304

Determining electro negativity

Is there a way to figure out the electro negativity of atoms? Or would the electro negativity values be given?

Thanks
Fri Oct 14, 2016 11:22 am
Forum: Properties of Light
Topic: Emit Light
Replies: 3
Views: 571

Emit Light

When light is emitted, does it always mean that the change in energy is going to be negative?

Thanks
Mon Oct 03, 2016 12:34 pm
Forum: Empirical & Molecular Formulas
Topic: Workbook: Quiz 1 2015 #5 Find empirical formula [ENDORSED]
Replies: 1
Views: 493

Workbook: Quiz 1 2015 #5 Find empirical formula[ENDORSED]

6.40 g of a compound was burned in the air and produced 8.80 g CO2 and 7.20 g H2O. Find the empirical formula of the compound. The answer says it is CH4O, but I did all the steps and checked multiple times but I keep getting CH2O. What did I do wrong? https://mail.google.com/mail/u/0/?ui=2&ik=94...
Thu Sep 29, 2016 4:07 pm
Forum: Limiting Reactant Calculations
Topic: Steps for Limiting Reactant Problems
Replies: 4
Views: 3184

Steps for Limiting Reactant Problems

Hi, so I just want to make sure I am correct, the general steps for limit reactant calculations is: 1. Balance Equation 2. Calculate molar mass of each reactant 3. Calculate # of moles of each 4. Compare how much of a reactant is needed according to the balanced reaction. Please comment if I missed ...