## Search found 52 matches

Thu Mar 15, 2018 11:00 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Half-cell concentrations
Replies: 1
Views: 135

### Half-cell concentrations

How do you calculate half-cell concentrations? I remember Dr. Lavelle mentioning it in class but I don't have it in my notes.
Wed Mar 14, 2018 10:16 pm
Forum: Experimental Details
Topic: Relationship between temperature and Le Chatelier's principle
Replies: 1
Views: 486

### Relationship between temperature and Le Chatelier's principle

Can someone explain how raising the temperature of a reaction, which increases the rate constant of the forward reaction and ultimately the equilibrium constant, is supported by Le Chatelier's principle?
Wed Mar 14, 2018 10:08 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Calculating activation energy from Arrhenius equation
Replies: 1
Views: 140

### Calculating activation energy from Arrhenius equation

If given 2 rate constants and the corresponding temperatures, like in exercise 61, does it matter which one we assign as k1,k2,T1,T2?
Fri Mar 09, 2018 10:12 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pseudo Rate Law [ENDORSED]
Replies: 3
Views: 285

### Pseudo Rate Law[ENDORSED]

The pseudo rate law is the rate law in between elementary steps, but under what conditions would we need to use this?
Fri Mar 09, 2018 10:08 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Intermediate and rate law [ENDORSED]
Replies: 3
Views: 233

### Re: Intermediate and rate law[ENDORSED]

I see, that makes sense! Does it have anything to do with the reactivity of the intermediate as well?
Fri Mar 09, 2018 9:57 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Kinetic information [ENDORSED]
Replies: 3
Views: 192

### Kinetic information[ENDORSED]

If kinetic information can support a proposed mechanism, why can't it prove the mechanism to be correct?
Fri Mar 09, 2018 9:55 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Intermediate and rate law [ENDORSED]
Replies: 3
Views: 233

### Intermediate and rate law[ENDORSED]

Why can't an intermediate be included in the rate law?
Mon Mar 05, 2018 12:35 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: Units of k
Replies: 8
Views: 689

### Units of k

How do you calculate the units of k for the order of each reactant?
Mon Mar 05, 2018 12:32 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: Overall reaction order
Replies: 3
Views: 271

### Overall reaction order

When would the overall reaction order be a fraction and what makes it different from other reactions?
Mon Mar 05, 2018 12:29 am
Forum: First Order Reactions
Topic: Half-life of first order reactions
Replies: 3
Views: 213

### Half-life of first order reactions

Is it correct to say that the greater the rate constant, the shorter the half-life is because it doesn't depend on the concentration of reactants?
Mon Mar 05, 2018 12:26 am
Forum: Second Order Reactions
Topic: Half-life of second order reactions
Replies: 2
Views: 205

### Half-life of second order reactions

Is the half-life of a second order reaction dependent or independent on reaction concentration?
Wed Feb 21, 2018 12:10 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Calculating standard potential [ENDORSED]
Replies: 1
Views: 139

### Calculating standard potential[ENDORSED]

For exercise 33 part A, the solutions manual states that the standard Gibbs free energy should be negative because it's the reverse of the formation reaction, but why would this be so?
Tue Feb 20, 2018 11:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard Reduction Potential
Replies: 3
Views: 211

### Standard Reduction Potential

In exercise 14.25, do the standard reduction potentials follow a periodic trend?
Sat Feb 17, 2018 8:18 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Dissolving
Replies: 2
Views: 193

### Re: Dissolving

Can we assume that any spontaneous reaction will dissolve? Does this apply to only this reaction?
Sat Feb 17, 2018 8:07 pm
Forum: Balancing Redox Reactions
Topic: Oxidizing & Reducing Agents
Replies: 6
Views: 424

### Re: Oxidizing & Reducing Agents

Oxidizing agents are the species that is reduced, or gaining electrons, because the oxidation number is being decreased. The reducing agents are the species that is oxidized, or losing electrons, because the oxidation number is being increased.
Tue Feb 13, 2018 12:01 am
Forum: Calculating Work of Expansion
Topic: Reversible vs irreversible
Replies: 4
Views: 256

### Re: Reversible vs irreversible

Can you give me an example?
Mon Feb 12, 2018 11:15 pm
Forum: Calculating Work of Expansion
Topic: Reversible vs irreversible
Replies: 4
Views: 256

### Reversible vs irreversible

Given an equation, how can you tell if it's reversible or irreversible?
Fri Feb 09, 2018 12:53 am
Forum: Balancing Redox Reactions
Topic: Anode vs cathode
Replies: 6
Views: 260

### Anode vs cathode

Is the anode always the side of the oxidation half-reaction and the cathode, the side with the reduction half reaction?
Fri Feb 09, 2018 12:50 am
Forum: Balancing Redox Reactions
Topic: Standard Reduction Potential
Replies: 3
Views: 226

### Standard Reduction Potential

Can someone explain how to balance half reactions when calculating the standard reduction potential? Do we treat the equations like how we would normally balance chemical reactions?
Fri Feb 09, 2018 12:44 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.17
Replies: 1
Views: 156

### 9.17

Can someone please explain the relationship between enthalpy and entropy according to Trouton's rule?
Sun Feb 04, 2018 1:16 am
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: Standard molar entropy
Replies: 1
Views: 168

### Standard molar entropy

Can someone explain the graphs of Figure 9.11 in section 9.7 of the textbook?
Sun Feb 04, 2018 1:06 am
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: Residual Entropy
Replies: 4
Views: 288

### Residual Entropy

What is residual entropy and how is it different from regular entropy?
Sun Feb 04, 2018 12:54 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy -/+
Replies: 4
Views: 228

### Re: Gibbs Free Energy -/+

A negative Gibbs Free Energy means that the energy of the products is less than the energy of the reactants. If it were the reverse, an input of energy would be needed, which is not favorable. Therefore, a negative Gibbs free energy is favored because it drives the reaction forward spontaneously.
Fri Jan 26, 2018 7:40 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Relation of degeneracy and entropy
Replies: 2
Views: 202

### Relation of degeneracy and entropy

Can someone explain what increasing/decreasing degeneracy does to entropy?
Fri Jan 26, 2018 7:37 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy of gas vs liquid vs solid
Replies: 7
Views: 2838

### Entropy of gas vs liquid vs solid

Why is the entropy of a gas much greater than that of a liquid or solid?
Fri Jan 26, 2018 7:33 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: Calculating degeneracy(W)
Replies: 3
Views: 379

### Calculating degeneracy(W)

How do you determine the number of states there are in a system?
Sat Jan 20, 2018 11:44 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity Properties
Replies: 3
Views: 163

### Heat Capacity Properties

Why is heat capacity an intensive property while specific heat capacity and molar heat capacity are extensive properties?
Sat Jan 20, 2018 11:35 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.37
Replies: 1
Views: 115

### Re: 8.37

You divide the number of joules by the number of moles because you want to find how much heat(q) is required to raise 1 mol of the substance to a certain temperature.
Sat Jan 20, 2018 11:32 am
Forum: Calculating Work of Expansion
Topic: 8.13 - Understanding the Solution
Replies: 2
Views: 219

### Re: 8.13 - Understanding the Solution

947kJ should be positive because the system is absorbing the heat in order to cool down, which means it's an endothermic process. Work done by the system produces a negative work value.
Tue Jan 09, 2018 10:08 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Molar Heat Capacity [ENDORSED]
Replies: 1
Views: 143

### Molar Heat Capacity[ENDORSED]

How does having additional vibrational modes increase a molecule's molar heat capacity?
Tue Jan 09, 2018 9:48 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Equipartition Theorem
Replies: 1
Views: 197

### Equipartition Theorem

What is the equipartition theorem used to calculate?
Tue Jan 09, 2018 9:43 pm
Forum: Calculating Work of Expansion
Topic: Work for reversible vs irreversible process
Replies: 3
Views: 225

### Work for reversible vs irreversible process

Why is it that more work is done for a reversible process than for a irreversible process?
Sat Dec 09, 2017 3:31 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: What is MO theory for? [ENDORSED]
Replies: 20
Views: 7326

### Re: What is MO theory for?[ENDORSED]

How does the number of paired or unpaired electrons relate to the magnetism of a molecule?
Sat Dec 09, 2017 3:19 pm
Forum: Bond Lengths & Energies
Topic: Bond Order
Replies: 6
Views: 612

### Re: Bond Order

Would the bond order of a CN radical be 1.5 then? Since there is a triple bond,3, and 2 atoms, would it be 3/2=1.5?
Sat Dec 02, 2017 5:39 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Problem 55 Part D
Replies: 1
Views: 152

### Problem 55 Part D

How do you explain the differences in pH based on molecular structure?
Sat Dec 02, 2017 5:02 pm
Forum: Calculating the pH of Salt Solutions
Topic: Calculating pH
Replies: 3
Views: 325

### Calculating pH

When calculating the logarithm to find the pH of a solution, why is there a negative sign?
Wed Nov 22, 2017 12:00 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Gas concentration
Replies: 2
Views: 206

### Re: Gas concentration

To convert between partial pressure and concentration of a gas, you would use the Ideal Gas Law: PV=nRT.
Simplifying the equation would give: concentration=P/(RT)
Tue Nov 21, 2017 11:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium constant
Replies: 4
Views: 192

### Re: Equilibrium constant

To find K(p), the ratio would be 1/P(r). Since the molar concentration of a solid or liquid does not change in a reaction, solids and liquids aren't included in K expression. You would only need to find the concentration of the reactants.
Fri Nov 17, 2017 3:25 pm
Forum: Sigma & Pi Bonds
Topic: Pi bonds
Replies: 6
Views: 929

### Re: Pi bonds

Since the electrons overlap side-by-side in pi bonds, rotating one atom would break the parallel orientation of the orbitals.
Fri Nov 17, 2017 3:14 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands
Replies: 2
Views: 157

### Re: Ligands

In order to clearly show which atom is being bound to the central atom, the ligands are sometimes written backwards.
Mon Nov 13, 2017 8:37 pm
Forum: Hybridization
Topic: Hybrid orbitals
Replies: 2
Views: 139

### Re: Hybrid orbitals

You can determine the number of hybrid orbitals by looking at the regions of electron density. Different shapes indicate different hybrids of valence atomic orbitals during bond formation.
Mon Nov 13, 2017 8:27 pm
Forum: Octet Exceptions
Replies: 2
Views: 257

Are radicals stable compounds even though they have an unpaired electron?
Sat Nov 04, 2017 3:37 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic and Covalent Bonds
Replies: 9
Views: 632

### Ionic and Covalent Bonds

What are the main differences between ionic and covalent bonds?
Sat Nov 04, 2017 3:34 pm
Forum: Resonance Structures
Topic: Resonance and energy
Replies: 2
Views: 177

### Re: Resonance and energy

Resonance structures spread multiple bond characters over a molecule, lowering the overall energy of the molecule.
Sun Oct 29, 2017 3:54 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ground state and electron configuration
Replies: 2
Views: 202

### Re: Ground state and electron configuration

If the electron configuration has the right number, direction, and spacing of the arrows, then the electron is in the ground state.
Sun Oct 29, 2017 3:47 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration of Gallium
Replies: 3
Views: 1985

### Electron Configuration of Gallium

According to the periodic table, the electron configuration of Ga is [Ar]4s^2 3d^10 4p^1. However, why did Dr. Lavelle write it as [Ar]3d^10 4s^2 4p^1 in class?
Sun Oct 22, 2017 11:48 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Wave Functions
Replies: 1
Views: 182

### Wave Functions

How are the wave functions of px, py, and pz derived?
Sun Oct 22, 2017 11:41 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital Orientation
Replies: 1
Views: 149

### Orbital Orientation

Does only the p orbital have lobes oriented along the x, y, z axes or do the other orbitals have different orientations as well?
Sat Oct 14, 2017 2:16 pm
Forum: Einstein Equation
Topic: 1.69 [ENDORSED]
Replies: 1
Views: 314

### Re: 1.69[ENDORSED]

a) An electron can only be ejected if a photon has the minimum energy equal to that of the work function for that metal strikes it. 1. E(work) = (2.93 eV)(1.602 18 x10^(19)JeV^(-1)) = 4.69 x 10^(-19)J 2. Calculate the energy for the red and violet laser using the equation E=hcλ ^(-1). 3. The laser w...
Sat Oct 14, 2017 1:58 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Change in energy of an electron [ENDORSED]
Replies: 3
Views: 249

### Re: Change in energy of an electron[ENDORSED]

The positive and negative signs only indicate whether the photon is emitted or absorbed, but the amount of energy that is used is always positive.
Hope this helps!
Fri Oct 06, 2017 12:52 am
Forum: Molarity, Solutions, Dilutions
Topic: G13
Replies: 2
Views: 284

### G13

How do you start this problem?
Fri Oct 06, 2017 12:32 am
Forum: Balancing Chemical Reactions
Topic: M9 Part A
Replies: 2
Views: 242

### M9 Part A

How do you find the net ionic equation for the reaction?