## Search found 65 matches

Wed Mar 13, 2019 7:38 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalyst Problems
Replies: 1
Views: 78

### 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: 74

### 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: 151

### 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: 219

### 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: 122

### 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: 132

### 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: 80

### 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: 139

### 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: 124

### 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: 163

### 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: 130

### 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: 123

### 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: 129

### 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: 11
Views: 767

### 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: 435

### 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: 335

### 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: 130

### 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: 141

### 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: 89

### #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: 128

### 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: 178

### 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: 365

### 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: 139

### 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: 134

### 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: 311

### 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: 104

### Homework 6th Edition #61

Wed Jan 16, 2019 6:35 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Percentage Ionization
Replies: 4
Views: 211

### 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: 157

### 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: 146

### 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: 209

### 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: 181

### 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: 164

### 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: 448

### 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: 121

### 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: 99

### 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: 174

### 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: 110

### 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: 55

### 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: 194

### 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: 110

### 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: 26

### 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: 2047

### 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: 160

### 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: 98

### 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: 136

### 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: 179

### 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: 53

### 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: 221

### 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: 97

### 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: 170

### 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: 117

### 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: 325

### 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: 88

### 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: 78

### 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: 106

### 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: 183

### 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: 90

### 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: 91

### 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: 550

### 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: 133

### 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: 60

### 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: 62

### 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: 93

### 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: 339

### 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: 1006

### 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...