## Search found 25 matches

Tue Mar 14, 2017 10:49 pm
Forum: Balancing Redox Reactions
Topic: Winter 2016 Midterm, Question 6
Replies: 2
Views: 369

### Re: Winter 2016 Midterm, Question 6

Thank you!
Tue Mar 14, 2017 8:53 pm
Forum: Balancing Redox Reactions
Topic: Winter 2016 Midterm, Question 6
Replies: 2
Views: 369

### Winter 2016 Midterm, Question 6

For this problem we have to write and the balance reduction and oxidation half reactions in part a & b for H + (aq)+Cr 2 O 7 2- (aq)+C 2 H 5 OH(aq)-->Cr 3+ +C 2 H 4 )(aq)+H 2 O(l) In part A, there is 2 electrons in the oxidation half reaction. Why is it 2 electrons instead of 1 if C goes from 2-...
Tue Mar 07, 2017 8:13 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Transition State and Psuedo-Equilibrium Rate Constant
Replies: 1
Views: 253

### Transition State and Psuedo-Equilibrium Rate Constant

I'm a bit confused about pages 85 and 86 in the course reader. On page 85, how can we tell that step 1 has a higher energy barrier? On page 86, what exactly is the psuedo-equilibrium constant and when/how is it used?
Thu Mar 02, 2017 5:46 pm
Forum: *Electrophiles
Topic: Neither electrophile nor nucleophile
Replies: 2
Views: 1844

### Neither electrophile nor nucleophile

What is an example of something that is neither an electrophile nor a nucleophile? Does such exist?
Mon Feb 20, 2017 10:12 pm
Forum: General Rate Laws
Topic: Rates
Replies: 1
Views: 290

### Rates

What is the difference between average rate and instantaneous rate?
Sun Feb 12, 2017 1:04 am
Forum: Balancing Redox Reactions
Topic: Midterm 2013, Q7
Replies: 5
Views: 396

### Re: Midterm 2013, Q7

Anyone here know if we will need to balance out the hydrogen and oxygen the half reactions for the midterm?
Thu Feb 09, 2017 3:42 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: equations
Replies: 1
Views: 243

### equations

There are various ways to calculate the work of an isobaric reaction such as w=-P(deltaV), w=-nR(deltaT), and w=-(deltan)RT. This also goes for calculating change in entropy, enthalpy, and heat. I am aware that some equations are listed but not all of them are. Will we be given the different equatio...
Wed Feb 01, 2017 11:31 pm
Forum: Administrative Questions and Class Announcements
Replies: 130
Views: 13392

### Re: Quiz 1 Preparation Answers

#8 on Quiz 1 Preparation says, "For reaction: 2C+2H2=C2H4, DeltaH= +52.3 kJ/mol and DeltaS= -53.07 J/K*mol at 298 K. At what temperature will this reaction be spontaneous?" Initially, I thought the formula needed to solve for the temperature was DeltaG= DeltaH - T*DeltaS but then I saw th...
Wed Feb 01, 2017 5:38 pm
Forum: Administrative Questions and Class Announcements
Replies: 130
Views: 13392

### Re: Quiz 1 Preparation Answers

For #11, do the units not have to cancel out?
Wed Jan 25, 2017 11:08 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Integral
Replies: 1
Views: 267

### Integral

When taking the negative integral from the initial volume to the final volume, why is PEX the integrand instead of PINT? found on page 22 of the course reader
Thu Jan 19, 2017 8:18 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Chapter 8, Problem 61
Replies: 5
Views: 518

### Re: Chapter 8, Problem 61

How do you know when you have to reverse the equation?
Thu Jan 19, 2017 7:57 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Chapter 8, Problem 61
Replies: 5
Views: 518

### Chapter 8, Problem 61

Calculate the reaction enthalpy for the synthesis of hydrogen bromide gas, H 2 (g)+Br 2 (l) -> 2HBr. The problem gives you 3 equations and their enthalpies but how do you use the three equations to obtain the reaction enthalpy for H 2 (g)+Br 2 (l) -> 2HBr. I tried to combine the equations like I did...
Sun Jan 15, 2017 5:12 pm
Forum: Phase Changes & Related Calculations
Topic: CLOSED vs ISOLATED
Replies: 3
Views: 326

### CLOSED vs ISOLATED

What is the difference between the two? How does the energy exchange with the surroundings?
Wed Nov 30, 2016 2:06 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Hydronium and Hydroxide
Replies: 2
Views: 319

### Hydronium and Hydroxide

Why do we use H2O and H3O+ when writing out equations?
Wed Nov 23, 2016 1:47 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE TABLE
Replies: 1
Views: 287

### ICE TABLE

Can someone please explain how to use the ice table and how to find the change in molar concentration (-x, x, 2x, etc...)?

Thank you!
Tue Nov 15, 2016 4:37 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: #4 in Quiz Prep 3 2015 [ENDORSED]
Replies: 1
Views: 317

### #4 in Quiz Prep 3 2015[ENDORSED]

For [Fe(Cl)4(en)]2- I got a coordination number of 5 because of the 4 Chlorine and the one ethelynediammine but the answer is 6. Am I supposed to count en as 2 bonds?
Tue Nov 08, 2016 10:36 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Cholorophyll Example in Course Reader
Replies: 1
Views: 228

### Cholorophyll Example in Course Reader

How is the MO Theory applied in the chlorophyll example on page 112 of the course reader?
Fri Nov 04, 2016 11:29 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 900446

### Re: Post All Chemistry Jokes Here

Anyone know any jokes about sodium?
.
.
.
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Na
Mon Oct 24, 2016 12:13 pm
Forum: Trends in The Periodic Table
Topic: CH 2, #61 [ENDORSED]
Replies: 2
Views: 341

### CH 2, #61[ENDORSED]

Which member of each pair has the smaller first ionization energy:
a) Ca or Mg; b) Mg or Na; c) Al or Na

How do you determine which is smaller? Should you refer to the periodic table? Also, does the "first ionization energy" just imply Ca+ and Mg+ or is it something different?

Thank you!
Tue Oct 18, 2016 9:35 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Aufbau's Principle [ENDORSED]
Replies: 3
Views: 415

### Re: Aufbau's Principle[ENDORSED]

Is this always the case or does it depend on the atom?
Mon Oct 17, 2016 3:51 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Aufbau's Principle [ENDORSED]
Replies: 3
Views: 415

### Aufbau's Principle[ENDORSED]

I'm not sure if someone already asked this but I'm still a bit confused. According to Aufbau's Principle 4s comes before 3d, but in the course reader for Scandium, 3d goes before 4s. Is Scandium an exception?
Fri Oct 14, 2016 10:36 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 900446

### Re: Post All Chemistry Jokes Here

What do you get when you cut an avocado into 6.0x10^23 pieces?

Guacamole!
Wed Oct 05, 2016 3:47 pm
Forum: *Shrodinger Equation
Topic: psi
Replies: 1
Views: 385

### psi

Is psi basically equal to the amplitude? And how can you find an electron with psi^2?
Wed Sep 28, 2016 4:39 pm
Forum: General Science Questions
Topic: Memorizing Constants
Replies: 2
Views: 559

### Memorizing Constants

Are we expected to have constants like Avagadro's Number and Planck's constant memorized or will they always be given?
Mon Sep 26, 2016 7:49 pm
Forum: Significant Figures
Topic: Easy Way to Calculate Sigfigs
Replies: 6
Views: 809

### Re: Easy Way to Calculate Sigfigs

So in other words,"trailing zeroes" are counted as significant figures if a decimal in present? Or am I interpreting that video wrong...?