Search found 58 matches

by rkusampudi
Sun Mar 18, 2018 6:46 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: complex molecules
Replies: 8
Views: 380

Re: complex molecules

The more the molecular complexity, the more the disorder, and thus the more the entropy.
by rkusampudi
Sun Mar 18, 2018 6:41 pm
Forum: Calculating Work of Expansion
Topic: Final Question W18: Reversible vs. Irreversible External Pressure
Replies: 4
Views: 232

Re: Final Question W18: Reversible vs. Irreversible External Pressure

I further defined a reversible
process as one that can be reversed by an infinitely small change in a variable
by rkusampudi
Sun Mar 18, 2018 6:34 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: State Functions
Replies: 4
Views: 285

Re: State Functions

I believe that the 4 points for the question indicated 4 answer choices that were correct.
by rkusampudi
Sun Mar 18, 2018 6:29 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Adiabatic Process
Replies: 4
Views: 271

Re: Adiabatic Process

An adiabatic process indicates that q=0.
by rkusampudi
Sun Mar 18, 2018 3:32 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 882470

Re: Post All Chemistry Jokes Here

The name's Bond. Ionic Bond. Taken, not shared.
by rkusampudi
Sun Mar 18, 2018 3:31 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 882470

Re: Post All Chemistry Jokes Here

A photon checks into a hotel and is asked if he needs any help with his luggage. He says, "No, I'm traveling light."
by rkusampudi
Sun Mar 18, 2018 3:27 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 882470

Re: Post All Chemistry Jokes Here

Making bad chemistry jokes because all the good ones Argon
by rkusampudi
Sun Mar 18, 2018 3:26 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 882470

Re: Post All Chemistry Jokes Here

Did you know that you can cool yourself to -273.15˚C and still be 0k?
by rkusampudi
Sun Mar 18, 2018 3:25 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 882470

Re: Post All Chemistry Jokes Here

Don't trust atoms, they make up everything.
by rkusampudi
Wed Mar 07, 2018 5:10 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 15.47
Replies: 1
Views: 79

Re: 15.47

On the tests they are usually given.
by rkusampudi
Wed Mar 07, 2018 5:10 pm
Forum: Zero Order Reactions
Topic: Units of K based on the order
Replies: 3
Views: 241

Re: Units of K based on the order

This is a useful equation to figure out the units:

K = M^-n+1 x s^-1
M = mol/liter
n = total reaction order
by rkusampudi
Wed Mar 07, 2018 4:50 pm
Forum: First Order Reactions
Topic: First Order Integrated Rate Law
Replies: 3
Views: 160

Re: First Order Integrated Rate Law

They seem to be interchangeable, but I'm not sure
by rkusampudi
Sun Mar 04, 2018 12:28 am
Forum: General Rate Laws
Topic: 15.39a
Replies: 3
Views: 140

Re: 15.39a

Perhaps because it is looking at the concentration and not the number of moles.
by rkusampudi
Sun Mar 04, 2018 12:25 am
Forum: First Order Reactions
Topic: half life
Replies: 2
Views: 116

Re: half life

Im assuming that you would treat each element individually in that case.
by rkusampudi
Sun Mar 04, 2018 12:23 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: 15.55 a
Replies: 3
Views: 108

Re: 15.55 a

A large equilibrium constant means that the products are favored.
by rkusampudi
Wed Feb 21, 2018 12:37 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: voltage
Replies: 1
Views: 87

Re: voltage

The units for voltage is joules per coulomb. The unit for Farraday's constant is coulombs per volt. Multiplying these and the number of moles together leaves joules per mol which is the unit of Gibbs free energy.
by rkusampudi
Wed Feb 21, 2018 12:26 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calculating K
Replies: 3
Views: 138

Re: Calculating K

Of the equations you listed, only the first two equations allow for you to calculate K, the last equation is Q which is the reaction quotient not the equilibrium constant.
by rkusampudi
Tue Feb 13, 2018 5:10 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Useful Table of Thermodynamic definitions!!
Replies: 2
Views: 277

Re: Useful Table of Thermodynamic definitions!!

This is so helpful!
I think one good thing to add would be that reversible work occurs under ideal conditions and is very rare in real life.
by rkusampudi
Tue Feb 13, 2018 5:06 pm
Forum: Van't Hoff Equation
Topic: Derivation
Replies: 5
Views: 280

Derivation

Will we be tested on the derivation of this equation?
by rkusampudi
Tue Feb 13, 2018 5:05 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Problem 9.47
Replies: 1
Views: 98

Problem 9.47

For part A is it also possible to use the work equation?
As in: q/T = -w/T

How would that work?
by rkusampudi
Tue Feb 06, 2018 8:13 pm
Forum: Balancing Redox Reactions
Topic: Basic vs. Acidic
Replies: 6
Views: 168

Re: Basic vs. Acidic

I would add that if OH- and H+ ions are on the same side, then they are written as water.
by rkusampudi
Tue Feb 06, 2018 8:07 pm
Forum: Balancing Redox Reactions
Topic: Transition Metals
Replies: 4
Views: 136

Transition Metals

Because the transition metals have variable oxidation states, which ones are we expected to memorize or will they be given?
by rkusampudi
Tue Feb 06, 2018 8:02 pm
Forum: Balancing Redox Reactions
Topic: Water in Redox reaction
Replies: 1
Views: 73

Water in Redox reaction

In today's (Wednesday week 5) lecture, Dr. Lavelle put water in the half-reaction for reduction. Is there a reason to do so?
by rkusampudi
Tue Jan 30, 2018 5:15 pm
Forum: Phase Changes & Related Calculations
Topic: Hw #8.49 standard state
Replies: 4
Views: 215

Re: Hw #8.49 standard state

Because it doesn't say otherwise and because all the given information assumes a standard state, it is a safe assumption to make.
by rkusampudi
Tue Jan 30, 2018 5:13 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: 9.25
Replies: 3
Views: 161

Re: 9.25

I think the simplest approach is to look at the shape of the molecule as well as the number of different elements involved (e.g. switching the positions of two oxygens doesn't count as a different arrangement). Here there are four atoms around the central sulfur atom and they are of two types
by rkusampudi
Tue Jan 30, 2018 5:08 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 9.13
Replies: 7
Views: 220

Re: 9.13

I think using nR allows us to cancel out the moles in the denominator but I am not sure.
by rkusampudi
Wed Jan 24, 2018 4:48 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 2
Views: 177

Midterm

Will our midterm basically cover chapter 8,9, and 11?
by rkusampudi
Wed Jan 24, 2018 4:42 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 3 Test Topic is endorsed
Replies: 37
Views: 1805

Re: Week 3 Test Topic is endorsed

There are no calculations on heat and internal energy but you do have to understand the concepts.
by rkusampudi
Wed Jan 24, 2018 4:39 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 882470

Re: Post All Chemistry Jokes Here

If you're not part of the solution, you're part of the precipitate.
by rkusampudi
Wed Jan 24, 2018 4:39 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 882470

Re: Post All Chemistry Jokes Here

Q: Why does hamburger yield lower energy than steak?
A: Because it's in the ground state.
by rkusampudi
Wed Jan 24, 2018 4:37 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 882470

Re: Post All Chemistry Jokes Here

Did you know that you can cool yourself to -273.15˚C and still be 0k?
by rkusampudi
Wed Jan 17, 2018 6:42 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Equations for gases using R
Replies: 4
Views: 156

Re: Equations for gases using R

I think there are some homework problems that use those equations indirectly in order to derive other values. But I don't think those equations will be tested on directly because they were not touched on in a detailed manner in class.
by rkusampudi
Mon Jan 15, 2018 10:14 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Equations and formulas
Replies: 2
Views: 129

Equations and formulas

Will the formula and equation sheet be posted on the website like it is for Chem 14A?
by rkusampudi
Mon Jan 15, 2018 8:05 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework Problem 8.23
Replies: 1
Views: 93

Homework Problem 8.23

The solution indicates the use of the equation q=mC delta T. However the mass is not shown in the solution or indicated in the question. How do you solve this question without knowing the mass?
by rkusampudi
Mon Jan 08, 2018 7:56 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy and Volume of a System
Replies: 2
Views: 126

Re: Enthalpy and Volume of a System

From the textbook: The state function that allows us to keep track of energy changes at constant pressure is called the enthalpy, H: H = U + PV U, P, and V are the internal energy, pressure, and volume of the system With this being the case, I am assuming that the great the volume, the greater the e...
by rkusampudi
Mon Jan 08, 2018 7:51 pm
Forum: Phase Changes & Related Calculations
Topic: Topics covered for Test 1 [ENDORSED]
Replies: 1
Views: 151

Topics covered for Test 1 [ENDORSED]

Does anyone know what topics will be covered in Test 1? Is it only Chapter 8?
by rkusampudi
Mon Jan 08, 2018 5:30 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Strength of Interactions in a Solid
Replies: 3
Views: 149

Strength of Interactions in a Solid

In a conceptual paragraph in the textbook, it said that when a solid melts, the molecules can move more freely,
but the interactions between them remain as strong. Does anyone understand why this is true?
by rkusampudi
Sat Dec 09, 2017 7:30 pm
Forum: Identifying Acidic & Basic Salts
Topic: Salts
Replies: 3
Views: 442

Re: Salts

Just to make sure, salts will not be covered on the final exam due to the fires.
by rkusampudi
Tue Nov 28, 2017 8:32 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: change in temperature
Replies: 4
Views: 200

Re: change in temperature

A change in temperature will always favor the exothermic reaction whether it is an increase or decrease.
by rkusampudi
Tue Nov 28, 2017 8:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar or nonpolar
Replies: 1
Views: 131

Re: polar or nonpolar

Drawing the Lewis structures definitely helps because you are essentially looking at the symmetry of dipole moments in the molecule. If there is no one direction of electron density it is non-polar and if there is it's polar.
by rkusampudi
Sun Nov 26, 2017 8:43 pm
Forum: Naming
Topic: Cyano vs Cyanido
Replies: 1
Views: 125

Cyano vs Cyanido

The solution manual sometimes uses cyano but the table in the textbook that has the steps for naming uses cyanido. Are they interchangeable?
by rkusampudi
Sun Nov 26, 2017 8:40 pm
Forum: Naming
Topic: Charge of a Ligand
Replies: 2
Views: 132

Charge of a Ligand

Do we just have to memorize ligands and their charges, or is there a manner in which we can find them?
by rkusampudi
Tue Nov 14, 2017 5:10 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs and Bond Angle
Replies: 3
Views: 161

Lone Pairs and Bond Angle

Could someone clarify the relationship between lone pairs and bond angles? I understand that the bond angles are "strained" by the lone pairs but am not quite sure how to show that in our answers.
by rkusampudi
Tue Nov 14, 2017 5:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs Angular
Replies: 7
Views: 326

Bent vs Angular

Just to clarify, Dr.Lavelle uses the terminology "bent" when describing molecular shape while the textbook seems to use "angular" to mean the same thing. Are those terms interchangeable?
by rkusampudi
Sat Nov 11, 2017 9:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Resonance
Replies: 3
Views: 168

Resonance

Does resonance have an impact on the molecular shape? How do we decide which Lewis structure to base our VSEPR theory on?
by rkusampudi
Sat Nov 11, 2017 9:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angle Exceptions
Replies: 3
Views: 284

Bond Angle Exceptions

As I was reading the textbook, I noticed that many molecular shapes have bond angles that are different from what is expected of that shape. Is there any way to predict these exceptions or do they have to be memorized?
EX: the HOH bond angle
by rkusampudi
Wed Nov 01, 2017 1:13 pm
Forum: Coordinate Covalent Bonds
Topic: Coordinate Covalent Bonds - Lewis Acids and Bases [ENDORSED]
Replies: 1
Views: 241

Coordinate Covalent Bonds - Lewis Acids and Bases [ENDORSED]

In one of the answers on this forum, the moderator answered that an atom that donates two electrons is a Lewis base. I'm a little confused about the relationship between coordinate covalent bonds and Lewis Acids and Bases. Thank you for the help!
by rkusampudi
Wed Nov 01, 2017 1:05 pm
Forum: Trends in The Periodic Table
Topic: Noble Gas Electron Affinity
Replies: 3
Views: 439

Re: Noble Gas Electron Affinity

The trend in electron affinity is best applied to elements that do not have a full octet and thus benefit from additional electrons that allow them to be more stable. Thus the halogens have extremely high electron affinity because the only require one more electron to fulfill their octet, but the tr...
by rkusampudi
Tue Oct 24, 2017 10:43 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: f-block
Replies: 3
Views: 198

f-block

Could someone explain the layout of the f-block on the periodic table?
by rkusampudi
Tue Oct 24, 2017 10:42 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration writing
Replies: 8
Views: 339

Electron Configuration writing

I just have a pretty simple question about the manner in which we write electron configuration. In lectures in was written in order of the periodic table (putting 3d after 4s) but in my discussion, we were told to order it in terms of principal quantum number. Which way is correct?
by rkusampudi
Wed Oct 18, 2017 3:11 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Post Module Question #16
Replies: 2
Views: 153

Re: Post Module Question #16

The correct answer is C. The textbook says if one property is known the other cannot be known simultaneously.
by rkusampudi
Wed Oct 18, 2017 3:07 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: E-p distribution
Replies: 2
Views: 137

E-p distribution

During Wednesday's lectur of Week 3, can someone explain what Dr.Lavelle meant by the term e-p distribution?
by rkusampudi
Wed Oct 11, 2017 8:45 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Energy Level Series
Replies: 2
Views: 146

Re: Energy Level Series

I would like to add that there is also the Paschen series which has a lower energy level of n=3.
by rkusampudi
Wed Oct 11, 2017 8:41 pm
Forum: Limiting Reactant Calculations
Topic: Net moles produced (Test question)
Replies: 3
Views: 238

Net moles produced (Test question)

In one of the questions on our test, it asked for the net moles of gas produced. However, in the calculation, it added the total number of moles produced on the product side (including that of H2O which I assumed was in liquid form). When questions ask for net moles produced do we just include the m...
by rkusampudi
Tue Oct 10, 2017 5:55 pm
Forum: Limiting Reactant Calculations
Topic: Net moles produced (Test question) [ENDORSED]
Replies: 2
Views: 236

Net moles produced (Test question) [ENDORSED]

In one of the questions on our test, it asked for the net moles of gas produced. However, in the calculation, it added the total number of moles produced on the product side (including that of H2O which I assumed was in liquid form). When questions ask for net moles produced do we just include the m...
by rkusampudi
Mon Oct 02, 2017 11:45 pm
Forum: Balancing Chemical Reactions
Topic: Prep Quiz 2015 #7
Replies: 2
Views: 302

Re: Prep Quiz 2015 #7

All combustion reactions follow the basic setup of hydrocarbon + O2 (g) -> CO2 (g) + H2O (l).
You put the hydrocarbon in this set up and balance the equation as necessary.
by rkusampudi
Mon Oct 02, 2017 11:38 pm
Forum: Empirical & Molecular Formulas
Topic: How to tell if Empirical and Molecular Formula are the same? [ENDORSED]
Replies: 2
Views: 257

Re: How to tell if Empirical and Molecular Formula are the same? [ENDORSED]

I guess the quickest way is to estimate the molar mass of the empirical formula in your head without doing any calculation. and compare that to the given mass. If it is not close, you know that the molecular formula is a multiple of the empirical formula.

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