to use T1-T2 not T2-T1
Search found 63 matches
- Tue Mar 12, 2019 4:06 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Homework 15.63
- Replies: 2
- Views: 138
Re: Homework 15.63
Don't forget that in the form ln(
)=(
)
-
)
to use T1-T2 not T2-T1
to use T1-T2 not T2-T1
- Tue Mar 12, 2019 12:46 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Frequency Factor
- Replies: 1
- Views: 88
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?
- 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: 90
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...
- 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: 343
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?
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?
- Mon Mar 04, 2019 11:58 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Elementary Reactions and Reaction Mechanisms
- Replies: 2
- Views: 141
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?
- Mon Mar 04, 2019 11:52 pm
- Forum: General Rate Laws
- Topic: Overall Order
- Replies: 3
- Views: 174
Overall Order
What is the purpose of knowing the overall order of a reaction?
- Mon Mar 04, 2019 11:44 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: K
- Replies: 2
- Views: 191
K
Is the value of K determined by experimental data using the initial rate/molar concentration?
- Wed Feb 27, 2019 5:14 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Electrochemical Series
- Replies: 2
- Views: 153
Electrochemical Series
Can someone please explain what the electrochemical series is and what it has to do with a redox couple?
- Wed Feb 27, 2019 5:09 pm
- Forum: Balancing Redox Reactions
- Topic: 14.17 6th Edition [ENDORSED]
- Replies: 2
- Views: 174
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?
- 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: 83
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?
- Wed Feb 20, 2019 11:59 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation Numbers
- Replies: 2
- Views: 133
Oxidation Numbers
What are some exceptions/special rules we should memorize for the oxidation numbers of molecules in order to balance the redox reactions?
- Wed Feb 20, 2019 11:57 pm
- Forum: Van't Hoff Equation
- Topic: When Delta S is constant
- Replies: 1
- Views: 135
When Delta S is constant
Can someone please re-explain what Lavelle meant when he said S isn't actually constant but
S is?
- 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: 245
Salt Bridge/Porous Disk
I'm not sure I caught what the purpose of these two are.
- Sun Feb 17, 2019 1:17 pm
- Forum: Van't Hoff Equation
- Topic: Different Constants of Eqn
- Replies: 3
- Views: 199
Different Constants of Eqn
Would we use the original Van't Hoff Equation: lnK=-
for constant temperatures?
- Sun Feb 17, 2019 1:17 pm
- Forum: Van't Hoff Equation
- Topic: Different Constants of Eqn
- Replies: 2
- Views: 166
Different Constants of Eqn
Would we use the original Van't Hoff Equation: lnK=-
for constant temperatures?
- 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: 206
Calculating G if H and S are gven
Can someone please explain why we assume
G is 0 when H and S are given?
- Sun Feb 17, 2019 1:07 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Midterm Question
- Replies: 8
- Views: 352
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?
- Thu Feb 07, 2019 9:04 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Molar Heat Capacity
- Replies: 3
- Views: 194
Molar Heat Capacity
Why is molar heat capacity of an ideal gas greater at a constant pressure greater than at a constant volume?
- Thu Feb 07, 2019 8:55 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Definitions of Heat Capacities
- Replies: 2
- Views: 165
Definitions of Heat Capacities
What's the difference between heat capacity, specific heat capacity, and molar heat capacity?
- 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: 183
Bond Enthalpy
Why are bond enthalpies always positive?
- Wed Jan 30, 2019 9:53 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Forms of U Equations
- Replies: 3
- Views: 186
Forms of U Equations
How can you tell when to use
U=w vs
U=w+q vs
U=q?
- 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: 87
Problem 8.11 6th Edition
Why does the reversible process do more work than the non-reversible process?
- Wed Jan 30, 2019 9:24 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Internal Energy
- Replies: 1
- Views: 84
Internal Energy
Why can't the total internal energy of a system be measured?
- 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: 153
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.
- 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: 219
H and Q
What's the difference between
H and Q?
- 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: 301
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?
- Wed Jan 16, 2019 5:34 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Superacids and Superbases
- Replies: 1
- Views: 177
Superacids and Superbases
What are some examples of superacids and superbases and what makes them have such a high concentration of H3O+ or OH–?
- 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: 232
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.
- Wed Jan 16, 2019 5:25 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Catalysts
- Replies: 7
- Views: 401
Catalysts
Why don't catalysts affect the equilibrium composition of a reaction mixture?
- Sat Jan 12, 2019 3:43 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Values of K
- Replies: 2
- Views: 111
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?
- Sat Jan 12, 2019 3:28 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Example in Class
- Replies: 7
- Views: 259
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.
- Sat Jan 12, 2019 3:22 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Liquids and Solids
- Replies: 3
- Views: 66
Liquids and Solids
Why aren't reactants and products in the liquid and solid phases not included when calculating K?
- Wed Dec 05, 2018 2:29 pm
- Forum: Amphoteric Compounds
- Topic: Question about the Outline
- Replies: 1
- Views: 109
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?
- Wed Dec 05, 2018 2:08 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Terminology
- Replies: 2
- Views: 125
Terminology
Is the term "chelating agent" only used to refer to chelates that remove metal ions out of solutions?
- Wed Dec 05, 2018 12:27 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Square Planar Complex
- Replies: 1
- Views: 106
Square Planar Complex
Why is it that the TM with an electron configuration of d8 have ligands arranged in a square planar configuration?
- Sat Dec 01, 2018 8:55 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination #
- Replies: 2
- Views: 102
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?
- Sat Dec 01, 2018 8:52 pm
- Forum: Naming
- Topic: With Respect to the Final
- Replies: 9
- Views: 481
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?
- Tue Nov 27, 2018 4:59 pm
- Forum: Hybridization
- Topic: Hybrid Orbitals Notation?
- Replies: 2
- Views: 95
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
h1= s+21/2py
- Sat Nov 24, 2018 9:13 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma Bonds
- Replies: 2
- Views: 148
Sigma Bonds
Is it impossible to have more than one sigma bond in a set of bonds? Why or why not?
- 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: 120
Visualizing a Dimer
Are dimers, pairs of identical molecules, only be linked by hydrogen bonds? Or can the other intermolecular forces bind them?
- 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: 107
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?
- Sun Nov 18, 2018 12:04 pm
- Forum: Hybridization
- Topic: Conceptual Question
- Replies: 2
- Views: 139
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?
- Sun Nov 18, 2018 12:02 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Geometry and Lone Pairs
- Replies: 1
- Views: 40
Geometry and Lone Pairs
Do all see-saw shaped molecules only have one lone pair of electrons?
- Wed Nov 14, 2018 8:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape
- Replies: 6
- Views: 267
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?
- Sat Nov 10, 2018 11:43 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar and Nonpolar Molecules
- Replies: 4
- Views: 215
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?
- Sat Nov 10, 2018 11:28 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pair Repulsion
- Replies: 1
- Views: 136
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?
- Sat Nov 10, 2018 11:15 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Geometric Shape and Bond Angle
- Replies: 3
- Views: 314
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"?
- Sun Nov 04, 2018 3:45 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration for Tungsten
- Replies: 1
- Views: 77
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?
- Sat Nov 03, 2018 5:45 pm
- Forum: Resonance Structures
- Topic: ????
- Replies: 2
- Views: 178
????
"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...
- Sat Nov 03, 2018 5:25 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Exceptions
- Replies: 2
- Views: 82
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?
- Fri Nov 02, 2018 1:12 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Test Question 1a
- Replies: 2
- Views: 171
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, ...
- Sat Oct 27, 2018 8:09 pm
- Forum: Trends in The Periodic Table
- Topic: Inert Pair
- Replies: 1
- Views: 123
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.
- Sat Oct 27, 2018 7:59 pm
- Forum: Trends in The Periodic Table
- Topic: Diagonal Relationships
- Replies: 2
- Views: 177
Diagonal Relationships
Are diagonal neighbor elements as similar to properties of elements in the same group?
- Sat Oct 27, 2018 7:55 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Magnetic Spin Number
- Replies: 5
- Views: 220
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?
- Thu Oct 18, 2018 6:08 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Equation
- Replies: 6
- Views: 383
Equation
What is the significance of h/4
in Heisenberg's uncertainty equation?
- Thu Oct 18, 2018 6:01 pm
- Forum: *Particle in a Box
- Topic: Shape of Wavefunction
- Replies: 4
- Views: 720
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)?
- Thu Oct 18, 2018 1:04 am
- Forum: Einstein Equation
- Topic: Question 1.25
- Replies: 1
- Views: 94
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...
- Thu Oct 11, 2018 10:38 pm
- Forum: Photoelectric Effect
- Topic: Kinetic Energy of Electrons
- Replies: 2
- Views: 144
Kinetic Energy of Electrons
Why is it that the kinetic energy of ejected electrons increases linearly with the frequency of radiation?
- Thu Oct 11, 2018 10:26 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Rydberg's Constant
- Replies: 1
- Views: 114
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?
- Thu Oct 11, 2018 10:11 pm
- Forum: Properties of Light
- Topic: Intensity
- Replies: 2
- Views: 73
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.
- Wed Oct 03, 2018 11:08 pm
- Forum: Balancing Chemical Reactions
- Topic: Extensive v. Intensive Property [ENDORSED]
- Replies: 6
- Views: 855
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.
- Wed Oct 03, 2018 10:42 pm
- Forum: Balancing Chemical Reactions
- Topic: Concept Question for #M15
- Replies: 2
- Views: 160
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.
- Tue Oct 02, 2018 10:21 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Question G23
- Replies: 3
- Views: 156
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...