Search found 65 matches
- Wed Mar 13, 2019 7:38 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Catalyst Problems
- Replies: 1
- Views: 178
Catalyst Problems
Will we have any problems that involve catalysts? If so, what would they look like?
- Wed Mar 13, 2019 7:37 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Arrhenius Equation
- Replies: 1
- Views: 211
Arrhenius Equation
For the Arrhenius equation, is ln( k2/k1 ) = (Ea/R) * (1/T1 - 1/T2) the same as ln k= -ea/rt + ln A?
- Wed Mar 13, 2019 7:33 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Catalysts vs Intermediates
- Replies: 4
- Views: 442
Catalysts vs Intermediates
Today in lecture Lavelle explained the difference between catalysts and intermediates, but I still don't understand how you can decipher between the two?
- Tue Mar 05, 2019 6:55 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Finding Order for Each Reactant
- Replies: 4
- Views: 506
Finding Order for Each Reactant
When finding the order for each reactant to write the rate law, does the order of the concentrations matter when you compare experiments (for example, should it be rate 2/rate 1 or rate 1/rate 2)?
- Tue Mar 05, 2019 6:36 pm
- Forum: First Order Reactions
- Topic: First Order Integrated Law
- Replies: 3
- Views: 333
First Order Integrated Law
Why is the equation ln([A]t[A]0)=−kt also written as ln([A]0[A]t)=kt? Are they the same thing?
- Tue Mar 05, 2019 5:25 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Homework 15.17 6th Edition
- Replies: 1
- Views: 294
Homework 15.17 6th Edition
For problem 17 in the 6th edition, part a asks us to find the order for each reactant and the overall order of the reaction. When finding the order with respect to A, I assume that we need to look at experiments 2 and 4, but the concentrations for C are different. Is this a typo?
- Mon Feb 25, 2019 6:53 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: The Nernst Equation
- Replies: 1
- Views: 180
The Nernst Equation
In the 6th edition, the textbook goes over example 14.10: Using the Nernst Equation to find a Concentration. I don't understand where the ln Q= -0.42V/0.02593V came from. Can someone explain?
- Mon Feb 25, 2019 6:47 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation
- Replies: 2
- Views: 298
Nernst Equation
Does n in the Nernst equation represent the number of electrons?
- Mon Feb 25, 2019 6:11 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation
- Replies: 1
- Views: 234
Nernst Equation
In the 6th edition of the textbook, example 14.9 Using the Nernst equation to predict a cell potential sets the reaction quotient as Zn over Cu. Why is that?
- Mon Feb 25, 2019 5:31 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Redox Reactions
- Replies: 3
- Views: 368
Balancing Redox Reactions
When canceling excess H20 molecules, does it matter which side of the reaction your H2O molecules are in?
- Tue Feb 19, 2019 8:18 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Homework 9.65 6th Edition
- Replies: 2
- Views: 350
Homework 9.65 6th Edition
For 9.65 in the 6th edition, would you determine if compounds become less stable with respect to the elements as the temperature is raised by looking at their entropy? Or does it have to do with Gibbs free energy?
- Tue Feb 19, 2019 8:15 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: ΔG= ΔH -TΔS
- Replies: 2
- Views: 338
ΔG= ΔH -TΔS
Should you convert all the units into kJ/mol in the beginning of the problem or can you wait until the end when solving for ΔG with ΔG= ΔH -TΔS?
- Tue Feb 19, 2019 8:12 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Homework 6th Edition 9.63
- Replies: 3
- Views: 359
Homework 6th Edition 9.63
For 9.63, how would you determine which are stable with respect to the decomposition into their elements?
- Wed Feb 13, 2019 10:06 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Isobaric
- Replies: 12
- Views: 1612
Isobaric
I understand that isobaric means that pressure is constant and ΔP=0, but what equation does it play a role in?
- Wed Feb 13, 2019 10:04 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: ΔS=q/t
- Replies: 8
- Views: 906
ΔS=q/t
When looking at the equation ΔS=q/t, could we say that ΔS=nΔH/T as well?
- Wed Feb 13, 2019 10:03 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: ΔU= 3/2nRT
- Replies: 5
- Views: 731
ΔU= 3/2nRT
Will we ever need to use ΔU=3/2nrt?
- Wed Feb 06, 2019 6:24 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy as Temperature Increases
- Replies: 2
- Views: 350
Entropy as Temperature Increases
As temperature increases, ∆S decreases, and I know this is because temperature is the denominator of the equation ∆S= -∆H/T, but what is the conceptual reason for this?
- Wed Feb 06, 2019 6:20 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Entropy Change Due to Temperature Change
- Replies: 3
- Views: 336
Entropy Change Due to Temperature Change
When finding entropy changes due to a temperature change, I'm still confused as to when we are supposed to use Cv= 3/2R and Cp= 5/2. Can someone explain?
- Wed Feb 06, 2019 6:18 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: #25 Homework 6th Edition
- Replies: 1
- Views: 236
#25 Homework 6th Edition
For #25, I understand that there are 6 different positions or orientations for the molecule SO2F2, but how to we find what 6 is to the power of?
- Tue Jan 29, 2019 6:13 pm
- Forum: Phase Changes & Related Calculations
- Topic: Internal Energy
- Replies: 1
- Views: 256
Internal Energy
How is internal energy stored as both molecular kinetic and potential energy?
- Tue Jan 29, 2019 6:03 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy
- Replies: 4
- Views: 413
Enthalpy
Why is the change in enthalpy equal to heat absorbed or released? How does that work?
- Tue Jan 29, 2019 5:33 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Best Method
- Replies: 7
- Views: 788
Best Method
Lavelle mentioned in lecture that bond enthalpies were not very accurate when calculating reaction enthalpies. Out of the remaining 2 methods, which one gives you a more accurate number?
- Thu Jan 24, 2019 4:52 pm
- Forum: Phase Changes & Related Calculations
- Topic: Reversible and Irreversible Process
- Replies: 3
- Views: 330
Reversible and Irreversible Process
How do you tell when you are dealing with a reversible and irreversible process?
- Thu Jan 24, 2019 4:49 pm
- Forum: Phase Changes & Related Calculations
- Topic: ΔH and ΔU
- Replies: 2
- Views: 296
ΔH and ΔU
What is the relationship between ΔH and ΔU?
- Thu Jan 24, 2019 4:41 pm
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy and States
- Replies: 8
- Views: 749
Enthalpy and States
Does the state of matter affect the enthalpy?
- Wed Jan 16, 2019 6:41 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Homework 6th Edition #61
- Replies: 1
- Views: 145
Homework 6th Edition #61
This problem requires us to work backwards, how would I go about this problem?
- Wed Jan 16, 2019 6:35 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Percentage Ionization
- Replies: 4
- Views: 488
Percentage Ionization
Is percentage ionization the same as percentage deprotonation and protonation, as mentioned in the textbook?
- Wed Jan 16, 2019 6:34 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Polyprotic Acids and Bases
- Replies: 2
- Views: 277
Polyprotic Acids and Bases
How do we identify polyprotic acids and bases?
- Wed Jan 09, 2019 4:25 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Calculating the Equilibrium Composition in ATP Hydrolysis
- Replies: 4
- Views: 348
Calculating the Equilibrium Composition in ATP Hydrolysis
In today's lecture, Lavelle mentioned that in the example of the ATP hydrolysis, to calculate the change in molarity you need to subtract the equilibrium molarity from the initial molarity of the ATP. How did that number apply to the ADP and Pi equilibrium concentrations?
- Wed Jan 09, 2019 4:22 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Temperature and Equilibrium
- Replies: 3
- Views: 332
Temperature and Equilibrium
I understand that raising the temperature of an equilibrium will tend to shift its composition in the endothermic direction of the reaction, but how do you know which side of the reaction is endothermic and exothermic?
- Wed Jan 09, 2019 4:19 pm
- Forum: Ideal Gases
- Topic: Inert Gases
- Replies: 3
- Views: 462
Inert Gases
Does anyone know why increasing pressure by introducing an inert gas have no effect on the equilibrium composition?
- Sun Dec 02, 2018 5:31 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Biological Compounds
- Replies: 3
- Views: 312
Biological Compounds
Lavelle mentioned that biological compounds with N lone pair can act as a base. What about acids?
- Sun Dec 02, 2018 5:26 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: Bases
- Replies: 4
- Views: 676
Bases
Can someone explain what makes bases have a soapy feel again?
- Sun Dec 02, 2018 5:25 pm
- Forum: Bronsted Acids & Bases
- Topic: Calculations Involving Strong Acid (or Base)
- Replies: 3
- Views: 213
Calculations Involving Strong Acid (or Base)
Lavelle talked about calculations involving strong acids or bases. Can someone provide an example of one?
- Sun Dec 02, 2018 5:23 pm
- Forum: Bronsted Acids & Bases
- Topic: Bronsted and Lewis Acids and Bases
- Replies: 3
- Views: 198
Bronsted and Lewis Acids and Bases
I am still having a hard time figuring out the difference between brosted and Lewis acids and bases. Can someone explain?
- Sun Dec 02, 2018 5:22 pm
- Forum: Biological Examples
- Topic: Biological Importance of Coordination Compounds
- Replies: 3
- Views: 357
Biological Importance of Coordination Compounds
What kind of questions will be on the final in regards to the biological importance of coordination compounds?
- Mon Nov 26, 2018 6:07 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Oxidation Number
- Replies: 4
- Views: 348
Re: Oxidation Number
How do you figure out that CN has a -1 charge? I tried drawing out the lewis structure but did not get that answer.
- Mon Nov 26, 2018 1:27 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelating Ligands
- Replies: 1
- Views: 149
Chelating Ligands
Can someone explain why chelating ligands can bind cations tightly?
- Mon Nov 26, 2018 1:24 pm
- Forum: Dipole Moments
- Topic: Dipole Moments
- Replies: 4
- Views: 342
Dipole Moments
Do dipole moments have to do with whether or not something is polar only?
- Mon Nov 26, 2018 1:02 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Oxidation Number
- Replies: 4
- Views: 348
Oxidation Number
Today Lavelle mentioned that the oxidation state of Fe in the formula [Fe(CN6)]4- is +2. How did we conclude to that?
- Mon Nov 19, 2018 2:05 pm
- Forum: Hybridization
- Topic: Bonds and Hybridization
- Replies: 1
- Views: 57
Bonds and Hybridization
Lavelle mentioned that double bonds is treated as a region when you are trying to find hybridization. Is that the same for triple bonds?
- Mon Nov 19, 2018 1:57 pm
- Forum: Hybridization
- Topic: Hybridized vs. Unhybridized Orbitals
- Replies: 4
- Views: 4298
Hybridized vs. Unhybridized Orbitals
What is the difference between hybridized and unhybridized orbitals?
- Mon Nov 19, 2018 1:55 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma and Pi Bonds [ENDORSED]
- Replies: 2
- Views: 301
Sigma and Pi Bonds [ENDORSED]
I know that Lavelle went over sigma and pi bonds, but I am still confused as to what the difference is between them, and their significance. How would a problem involving sigma and pi bonds show up?
- Tue Nov 13, 2018 3:34 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: The A in the VSEPR Formula [ENDORSED]
- Replies: 4
- Views: 253
The A in the VSEPR Formula [ENDORSED]
I understand that there is no subscript for A when writing the VSEPR formula in the "AXE" form, but does it have a purpose for being included in the formula?
- Tue Nov 13, 2018 2:19 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles [ENDORSED]
- Replies: 2
- Views: 580
Bond Angles [ENDORSED]
For molecules with an octahedral shape, the bond angles can either be 90 or 180 degrees. How do you know which one to apply?
- Tue Nov 13, 2018 2:15 pm
- Forum: Lewis Structures
- Topic: VSEPR Model
- Replies: 2
- Views: 337
VSEPR Model
When doing VSEPR models, there are questions that require you to know whether a molecule is polar or nonpolar. How can you tell?
- Wed Nov 07, 2018 3:11 pm
- Forum: Dipole Moments
- Topic: Intermolecular Forces
- Replies: 2
- Views: 144
Intermolecular Forces
Why do stronger intermolecular forces causes things to become solid, while weaker intermolecular forces causes things to become liquid?
- Wed Nov 07, 2018 3:04 pm
- Forum: Bond Lengths & Energies
- Topic: Calculating Bond Lengths
- Replies: 4
- Views: 498
Calculating Bond Lengths
How do you calculate bond lengths? Do you add the given lengths with a fraction of the number of resonance structures?
- Wed Nov 07, 2018 2:58 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Cause and Effect of Electrons in a Molecule
- Replies: 2
- Views: 290
Cause and Effect of Electrons in a Molecule
So to clarify, more electrons causes a molecule to become more distorted and polarizable?
- Fri Nov 02, 2018 4:27 pm
- Forum: Electronegativity
- Topic: Electronegativity vs. Ionization Energy
- Replies: 3
- Views: 345
Electronegativity vs. Ionization Energy
I understand that both electronegativity and ionization energy play a role when drawing a lewis structure, but which is more important to consider?
- Fri Nov 02, 2018 4:24 pm
- Forum: Lewis Structures
- Topic: H Element
- Replies: 2
- Views: 248
H Element
Can someone explain why Hydrogen can't be the center of a lewis structure?
- Fri Nov 02, 2018 4:23 pm
- Forum: Ionic & Covalent Bonds
- Topic: Electronegativity Difference
- Replies: 6
- Views: 631
Electronegativity Difference
What happens when the electronegativity difference is between 1.5 and 2?
- Wed Oct 24, 2018 3:10 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Coulomb's Law
- Replies: 1
- Views: 155
Coulomb's Law
I'm not sure if we have went over Coulomb's law yet, but what exactly does it state?
- Wed Oct 24, 2018 3:06 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configurations for Chromium and Copper
- Replies: 2
- Views: 191
Electron Configurations for Chromium and Copper
Could someone explain again why Chromium and Copper have exceptions when it comes to writing their electron configurations? What happens to the electrons?
- Mon Oct 22, 2018 3:36 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg's Equation
- Replies: 1
- Views: 251
Rydberg's Equation
Is the equation En=-hR/n^2 the same as 1/λ= R(1/I^2-1/j^2), with I being the lower energy level and j being the higher energy level? If so, why isn't Planck's constant used in the second equation?
- Wed Oct 17, 2018 3:34 pm
- Forum: Photoelectric Effect
- Topic: Post Module Assessment #25
- Replies: 2
- Views: 367
Re: Post Module Assessment #25
I agree, E=hv has both energy, (E) and frequency (v) in the equation, so it solidifies their relationship.
- Wed Oct 17, 2018 3:28 pm
- Forum: DeBroglie Equation
- Topic: DeBroglie Equation
- Replies: 2
- Views: 195
DeBroglie Equation
With the DeBroglie equation, are you able to use it to find the wavelength of protons and neutrons as well? It is not limited to electrons?
- Wed Oct 17, 2018 3:24 pm
- Forum: DeBroglie Equation
- Topic: 1.33
- Replies: 1
- Views: 160
Re: 1.33
I have yet to solve this problem, but I do know that for part a, you will need to use the DeBroglie equation of wavelength= h/mv. First, you will need to convert units before inputting anything into the equation. The velocity has to change from km*s^-1 to m*s^-1, so multiply (3.6 *10^3 km*s^-1) by (...
- Sun Oct 14, 2018 1:20 am
- Forum: Properties of Light
- Topic: E=hv
- Replies: 13
- Views: 1030
Re: E=hv
I've also seen E=hf once, does anyone know if that is the same as E=hv?
- Wed Oct 10, 2018 2:42 pm
- Forum: Properties of Light
- Topic: Homework Question 1A15
- Replies: 3
- Views: 227
Re: Homework Question 1A15
^ I was also having trouble with this question.
- Wed Oct 10, 2018 2:35 pm
- Forum: Properties of Light
- Topic: Clarification on Rydberg's Constant
- Replies: 1
- Views: 98
Clarification on Rydberg's Constant
Today in lecture Lavelle went over Rydberg's constant. I understand that it has to do with hydrogen, but can someone explain exactly what it is used for?
- Wed Oct 10, 2018 2:25 pm
- Forum: Properties of Light
- Topic: Problem 1.9 6th Edition
- Replies: 2
- Views: 135
Problem 1.9 6th Edition
Problem 1.9 in the 6th edition mentions: A college student recently had a busy day. Each of the student’s activities on that day (reading, getting a dental x-ray, making popcorn in a microwave oven, and acquiring a suntan) involved radiation from a different part of the electromagnetic spectrum. Com...
- Thu Oct 04, 2018 12:37 am
- Forum: Balancing Chemical Reactions
- Topic: Net Ionic Equation?
- Replies: 2
- Views: 201
Re: Net Ionic Equation?
I was wondering the same thing as well, I do believe it is good review however.
- Tue Oct 02, 2018 7:20 pm
- Forum: Empirical & Molecular Formulas
- Topic: Rounding
- Replies: 6
- Views: 610
Re: Rounding
I like the idea of turning the decimal into a fraction, it helps me know exactly what I need to multiply by to get a whole number!
- Mon Oct 01, 2018 8:42 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical and Molecular Formulas Module Post-Assement
- Replies: 1
- Views: 2573
Empirical and Molecular Formulas Module Post-Assement
I was completing the post assessment for the Empirical and Molecular Formulas module, and I am having problems with this question: L-Dopa, a drug used for a treatment of Parkinson's disease, is 54.82% C, 5.62% H, 7.10% N, and 32.46% O, and has a molar mass of 197.19 g/mol. What is the molecular form...