Search found 63 matches

by Kimberly 1H
Tue Mar 12, 2019 4:06 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Homework 15.63
Replies: 2
Views: 54

Re: Homework 15.63

Don't forget that in the form ln()=()-)


to use T1-T2 not T2-T1
by Kimberly 1H
Tue Mar 12, 2019 12:46 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Frequency Factor
Replies: 1
Views: 23

Frequency Factor

In class, Lavelle explained that the frequency factor of H+H-->H2 is 1 since the electron configuration is 1s, giving it a spherical shape. Are frequency factors solely dependent on orbital shapes?
by Kimberly 1H
Tue Mar 12, 2019 12:00 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6th edition 14.97
Replies: 1
Views: 44

6th edition 14.97

Use the data in Appendix 2B and the fact that, for the half-reaction F 2 (g)+2H + (aq)+2e - -->2HF(aq), E=3.03 V, to calculate the value of Ka for HF. The answer key shows that you're supposed to take the square root when you find K of the reaction in order to get K a , but I'm not sure I understand...
by Kimberly 1H
Mon Mar 11, 2019 10:32 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Typo In Reduction Potential of Water (6th Edition)
Replies: 1
Views: 115

Typo In Reduction Potential of Water (6th Edition)

In the homework section for electrolysis, it's given that the reduction of water:
2H2O(l)+2e--->H2(g)+2OH- E=-.42V at pH 7
but in appendix B it lists the reduction potential E=-.83.
Am I missing something or is this a typo?
by Kimberly 1H
Mon Mar 04, 2019 11:58 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Elementary Reactions and Reaction Mechanisms
Replies: 2
Views: 52

Elementary Reactions and Reaction Mechanisms

Can someone please explain how elementary reactions relate to reaction mechanisms? And how do the two terms explain the decomposition of O3 to O2?
by Kimberly 1H
Mon Mar 04, 2019 11:52 pm
Forum: General Rate Laws
Topic: Overall Order
Replies: 3
Views: 51

Overall Order

What is the purpose of knowing the overall order of a reaction?
by Kimberly 1H
Mon Mar 04, 2019 11:44 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: K
Replies: 2
Views: 59

K

Is the value of K determined by experimental data using the initial rate/molar concentration?
by Kimberly 1H
Wed Feb 27, 2019 5:14 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Electrochemical Series
Replies: 2
Views: 63

Electrochemical Series

Can someone please explain what the electrochemical series is and what it has to do with a redox couple?
by Kimberly 1H
Wed Feb 27, 2019 5:09 pm
Forum: Balancing Redox Reactions
Topic: 14.17 6th Edition [ENDORSED]
Replies: 2
Views: 74

14.17 6th Edition [ENDORSED]

Is the reason why potassium in potassium permanganate and chloride in iron(iii) chloride not included in the balanced redox reaction because they are spectator ions?
by Kimberly 1H
Wed Feb 27, 2019 5:01 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.15 6th Edition
Replies: 1
Views: 31

14.15 6th Edition

Can someone please explain why for part c the answer key says that KOH(aq) is included in the cell diagram?
by Kimberly 1H
Wed Feb 20, 2019 11:59 pm
Forum: Balancing Redox Reactions
Topic: Oxidation Numbers
Replies: 2
Views: 40

Oxidation Numbers

What are some exceptions/special rules we should memorize for the oxidation numbers of molecules in order to balance the redox reactions?
by Kimberly 1H
Wed Feb 20, 2019 11:57 pm
Forum: Van't Hoff Equation
Topic: When Delta S is constant
Replies: 1
Views: 41

When Delta S is constant

Can someone please re-explain what Lavelle meant when he said S isn't actually constant but S is?
by Kimberly 1H
Wed Feb 20, 2019 11:55 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge/Porous Disk
Replies: 5
Views: 81

Salt Bridge/Porous Disk

I'm not sure I caught what the purpose of these two are.
by Kimberly 1H
Sun Feb 17, 2019 1:17 pm
Forum: Van't Hoff Equation
Topic: Different Constants of Eqn
Replies: 3
Views: 85

Different Constants of Eqn

Would we use the original Van't Hoff Equation: lnK=- for constant temperatures?
by Kimberly 1H
Sun Feb 17, 2019 1:17 pm
Forum: Van't Hoff Equation
Topic: Different Constants of Eqn
Replies: 2
Views: 70

Different Constants of Eqn

Would we use the original Van't Hoff Equation: lnK=- for constant temperatures?
by Kimberly 1H
Sun Feb 17, 2019 1:09 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Calculating G if H and S are gven
Replies: 3
Views: 59

Calculating G if H and S are gven

Can someone please explain why we assume G is 0 when H and S are given?
by Kimberly 1H
Sun Feb 17, 2019 1:07 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Midterm Question
Replies: 8
Views: 141

Midterm Question

On the midterm, the last questions asked for the change in entropy of nitrogen gas that went through a change in temperature and volume. Did it matter if we used the C value of an ideal gas or of nitrogen itself?
by Kimberly 1H
Thu Feb 07, 2019 9:04 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Molar Heat Capacity
Replies: 3
Views: 57

Molar Heat Capacity

Why is molar heat capacity of an ideal gas greater at a constant pressure greater than at a constant volume?
by Kimberly 1H
Thu Feb 07, 2019 8:55 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Definitions of Heat Capacities
Replies: 2
Views: 34

Definitions of Heat Capacities

What's the difference between heat capacity, specific heat capacity, and molar heat capacity?
by Kimberly 1H
Thu Feb 07, 2019 8:53 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy
Replies: 4
Views: 53

Bond Enthalpy

Why are bond enthalpies always positive?
by Kimberly 1H
Wed Jan 30, 2019 9:53 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Forms of U Equations
Replies: 3
Views: 68

Forms of U Equations

How can you tell when to use U=w vs U=w+q vs U=q?
by Kimberly 1H
Wed Jan 30, 2019 9:42 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Problem 8.11 6th Edition
Replies: 1
Views: 34

Problem 8.11 6th Edition

Why does the reversible process do more work than the non-reversible process?
by Kimberly 1H
Wed Jan 30, 2019 9:24 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Internal Energy
Replies: 1
Views: 30

Internal Energy

Why can't the total internal energy of a system be measured?
by Kimberly 1H
Thu Jan 24, 2019 9:43 pm
Forum: Phase Changes & Related Calculations
Topic: Why steam at 100 C burns more than liquid at 100 C
Replies: 2
Views: 43

Re: Why steam at 100 C burns more than liquid at 100 C

To add onto it, steam condensing to liquid releases over 40 kJ of heat while liquid freezing into a solid releases around 5 kJ of heat.
by Kimberly 1H
Thu Jan 24, 2019 9:33 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: H and Q
Replies: 4
Views: 54

H and Q

What's the difference between H and Q?
by Kimberly 1H
Wed Jan 23, 2019 8:41 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6th Edition Problem 69 part B
Replies: 1
Views: 129

6th Edition Problem 69 part B

When finding the pH of .055M of AlCl3, the balanced chemical equation shows that there are 6 water molecules attached to Al and the overall charge is +3 on the reactants side. How come it can't be balanced with just 3 water molecules?
by Kimberly 1H
Wed Jan 16, 2019 5:34 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Superacids and Superbases
Replies: 1
Views: 69

Superacids and Superbases

What are some examples of superacids and superbases and what makes them have such a high concentration of H3O+ or OH?
by Kimberly 1H
Wed Jan 16, 2019 5:30 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pure Solids and Pure Liquids
Replies: 4
Views: 77

Re: Pure Solids and Pure Liquids

Consider the activities of pure solids and liquids as 1. Even when you include them in the calculation for equilibrium constant, they doesn't affect the result.
by Kimberly 1H
Wed Jan 16, 2019 5:25 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Catalysts
Replies: 7
Views: 110

Catalysts

Why don't catalysts affect the equilibrium composition of a reaction mixture?
by Kimberly 1H
Sat Jan 12, 2019 3:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Values of K
Replies: 2
Views: 46

Values of K

For values of K which are less than 10-3, the reaction favors the reactants and for K larger than 103 a reaction favors the product. But could someone help me clarify what "not strongly favored" means for intermediate values?
by Kimberly 1H
Sat Jan 12, 2019 3:28 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Example in Class
Replies: 7
Views: 131

Example in Class

In class, there was an example with N2, H2, and NH3. Lavelle explained that taking away the product would increase product yield, but I'm not sure if I understand why.
by Kimberly 1H
Sat Jan 12, 2019 3:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Liquids and Solids
Replies: 3
Views: 29

Liquids and Solids

Why aren't reactants and products in the liquid and solid phases not included when calculating K?
by Kimberly 1H
Wed Dec 05, 2018 2:29 pm
Forum: Amphoteric Compounds
Topic: Question about the Outline
Replies: 1
Views: 52

Question about the Outline

What should we know in order to "describe the chemical properties of amphoteric compounds"? And how would we draw these compounds if they act as both acids and bases?
by Kimberly 1H
Wed Dec 05, 2018 2:08 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Terminology
Replies: 2
Views: 36

Terminology

Is the term "chelating agent" only used to refer to chelates that remove metal ions out of solutions?
by Kimberly 1H
Wed Dec 05, 2018 12:27 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Square Planar Complex
Replies: 1
Views: 66

Square Planar Complex

Why is it that the TM with an electron configuration of d8 have ligands arranged in a square planar configuration?
by Kimberly 1H
Sat Dec 01, 2018 8:55 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination #
Replies: 2
Views: 43

Coordination #

Does the coordination number also refer to the total number of ligands in a compound and what is the significance of finding the coordination number?
by Kimberly 1H
Sat Dec 01, 2018 8:52 pm
Forum: Naming
Topic: With Respect to the Final
Replies: 9
Views: 172

With Respect to the Final

Will we be required to know how to name the compound or is it more important to know what the compound is made up of from the formula for the final? To what extent will this material be tested on the final?
by Kimberly 1H
Tue Nov 27, 2018 4:59 pm
Forum: Hybridization
Topic: Hybrid Orbitals Notation?
Replies: 2
Views: 71

Hybrid Orbitals Notation?

Each hybrid orbital is formed by the linear combinations of x amount of orbitals, but I don't understand the way they're denoted. In the textbook it lists the one of the 3 sp2 orbitals as:
h1= s+21/2py
by Kimberly 1H
Sat Nov 24, 2018 9:13 pm
Forum: Sigma & Pi Bonds
Topic: Sigma Bonds
Replies: 2
Views: 53

Sigma Bonds

Is it impossible to have more than one sigma bond in a set of bonds? Why or why not?
by Kimberly 1H
Sat Nov 24, 2018 9:08 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: Visualizing a Dimer
Replies: 1
Views: 62

Visualizing a Dimer

Are dimers, pairs of identical molecules, only be linked by hydrogen bonds? Or can the other intermolecular forces bind them?
by Kimberly 1H
Sat Nov 24, 2018 9:06 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: Van Der Waals Forces
Replies: 1
Views: 42

Van Der Waals Forces

The textbook states that intermolecular interactions depending on the inverse 6th power of separation between molecules are considered van der Waal forces, but are they also under the larger umbrella of london forces?
by Kimberly 1H
Sun Nov 18, 2018 12:04 pm
Forum: Hybridization
Topic: Conceptual Question
Replies: 2
Views: 58

Conceptual Question

What is the significance of learning about hybridization and sigma vs. pi bonds? Does it affect the chemical or physical properties of the molecule in any way?
by Kimberly 1H
Sun Nov 18, 2018 12:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Geometry and Lone Pairs
Replies: 1
Views: 19

Geometry and Lone Pairs

Do all see-saw shaped molecules only have one lone pair of electrons?
by Kimberly 1H
Wed Nov 14, 2018 8:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape
Replies: 6
Views: 127

Re: Molecular Shape

If the lone pair-lone pair electron repulsions are the strongest, then why can't the two pairs be situated opposite each other, as in a trigonal bipyramidal shape? One lone pair on top and one on the bottom? Wouldn't this result in a molecular geometry of a trigonal planar shape?
by Kimberly 1H
Sat Nov 10, 2018 11:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar and Nonpolar Molecules
Replies: 4
Views: 103

Polar and Nonpolar Molecules

Why do polar and nonpolar molecules not mix well, such as oil and water? Does it have to do with having different shapes or dipole/no dipole moments?
by Kimberly 1H
Sat Nov 10, 2018 11:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pair Repulsion
Replies: 1
Views: 127

Lone Pair Repulsion

How can Schrodinger's equation be used to predict the distortion of a bond angle caused by a lone pair of electrons?
by Kimberly 1H
Sat Nov 10, 2018 11:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Geometric Shape and Bond Angle
Replies: 3
Views: 192

Geometric Shape and Bond Angle

Is a molecule's geometric shape always determined by the degree of its bond angle? And what some examples of molecules whose bond angle are not "fixed by symmetry"?
by Kimberly 1H
Sun Nov 04, 2018 3:45 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration for Tungsten
Replies: 1
Views: 46

Electron Configuration for Tungsten

Why is the correct electron configuration for tungsten: [Xe]4f145d46s2 instead of [Xe]4f145d56s1? Why shouldn't the d orbital be filled halfway in this instance?
by Kimberly 1H
Sat Nov 03, 2018 5:45 pm
Forum: Resonance Structures
Topic: ????
Replies: 2
Views: 95

????

"Broadly speaking, the wavefunction that describes the resonance structure is a more accurate description of the electronic structure of the molecule than the wavefunction for any single structure alone, and the more accurate the wavefunction, the lower the corresponding energy." I have no...
by Kimberly 1H
Sat Nov 03, 2018 5:25 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge Exceptions
Replies: 2
Views: 59

Formal Charge Exceptions

A formal charge of 0 indicates a low energy structure, however the textbook also states that in some cases, the structure with the lowest formal charge is not the most likely. What are some factors that may contribute to this?
by Kimberly 1H
Fri Nov 02, 2018 1:12 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Test Question 1a
Replies: 2
Views: 125

Test Question 1a

The question follows: In an unusual situation, one nitrogen gas molecule is trapped in an alveoli sac. Alveoli are tiny sacs in the lungs whose average diameter is 1.5x10^-4m. Find the uncertainty in velocity of the nitrogen molecule within the sac. I substituted 1.5x10^-4m into the equation for x, ...
by Kimberly 1H
Sat Oct 27, 2018 8:09 pm
Forum: Trends in The Periodic Table
Topic: Inert Pair
Replies: 1
Views: 64

Inert Pair

I'm not sure I understand why a pair of low energy s-valence electrons being more difficult to remove during ion formation would result in an ion 2 units lower charge than expected.
by Kimberly 1H
Sat Oct 27, 2018 7:59 pm
Forum: Trends in The Periodic Table
Topic: Diagonal Relationships
Replies: 2
Views: 77

Diagonal Relationships

Are diagonal neighbor elements as similar to properties of elements in the same group?
by Kimberly 1H
Sat Oct 27, 2018 7:55 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Spin Number
Replies: 5
Views: 122

Magnetic Spin Number

If it's not possible for 2 electrons to have the same set of quantum numbers, how do parallel electrons exist in the same orbital?
by Kimberly 1H
Thu Oct 18, 2018 6:08 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Equation
Replies: 6
Views: 143

Equation

What is the significance of h/4 in Heisenberg's uncertainty equation?
by Kimberly 1H
Thu Oct 18, 2018 6:01 pm
Forum: *Particle in a Box
Topic: Shape of Wavefunction
Replies: 2
Views: 311

Shape of Wavefunction

What is the difference between describing a particle by its wavefunction (and most likely being found in the center of the box) versus (found in regions between the center and the walls)?
by Kimberly 1H
Thu Oct 18, 2018 1:04 am
Forum: Einstein Equation
Topic: Question 1.25
Replies: 1
Views: 52

Question 1.25

1.25 Sodium vapor lamps, used for public lighting, emit yellow light of wavelength 589 nm. How much energy is emitted by (a) an excited sodium atom when it generates a photon; (b) 5.00 mg of sodium atoms emitting light at this wavelength; (c) 1.00 mol of sodium atoms emitting light at this wavelengt...
by Kimberly 1H
Thu Oct 11, 2018 10:38 pm
Forum: Photoelectric Effect
Topic: Kinetic Energy of Electrons
Replies: 2
Views: 77

Kinetic Energy of Electrons

Why is it that the kinetic energy of ejected electrons increases linearly with the frequency of radiation?
by Kimberly 1H
Thu Oct 11, 2018 10:26 pm
Forum: Quantum Numbers and The H-Atom
Topic: Rydberg's Constant
Replies: 1
Views: 75

Rydberg's Constant

How was this constant empirically derived? Why is it 3.29x10^15 Hz to be exact, and how does it relate to the hydrogen spectrum?
by Kimberly 1H
Thu Oct 11, 2018 10:11 pm
Forum: Properties of Light
Topic: Intensity
Replies: 2
Views: 42

Intensity

I understand that intensity is the brightness of radiation and you calculate it by squaring the amplitude, but I'm not sure what units these are measured in.
by Kimberly 1H
Wed Oct 03, 2018 11:08 pm
Forum: Balancing Chemical Reactions
Topic: Extensive v. Intensive Property [ENDORSED]
Replies: 6
Views: 236

Re: Extensive v. Intensive Property [ENDORSED]

Extensive properties are dependent on size whereas intensive properties are independent of size. For example, mass and volume are affected by size. However, a substance's freezing point, temperature, or density doesn't change with size.
by Kimberly 1H
Wed Oct 03, 2018 10:42 pm
Forum: Balancing Chemical Reactions
Topic: Concept Question for #M15
Replies: 2
Views: 82

Re: Concept Question for #M15

Yes, the 2 represents the ratio of product that can be formed. In order to find out how much product you end up with, you multiply the ratio of product:reactant, in this case, 2:3.
by Kimberly 1H
Tue Oct 02, 2018 10:21 pm
Forum: Molarity, Solutions, Dilutions
Topic: Question G23
Replies: 3
Views: 98

Question G23

I'm not sure how to start solving this problem: In medicine, it is sometimes necessary to prepare solutions with a specific concentration of a given ion. A lab technician has made up a 100.0-mL solution containing 0.50 g of NaCl and 0.30 g of KCl, as well as glucose and other sugars. What is the con...

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