## Search found 49 matches

Sun Mar 18, 2018 4:14 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Work when pressure is constant
Replies: 6
Views: 518

### Re: Work when pressure is constant

Yes. If pressure is not constant, then we would use w=-nrt ln (v2/v1)
Sun Mar 18, 2018 4:13 am
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: complex molecules
Replies: 8
Views: 617

### Re: complex molecules

A larger molecule has greater entropy than smaller molecules
Sun Mar 18, 2018 4:10 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G at equilibrium
Replies: 1
Views: 270

### Delta G at equilibrium

Is delta G always equal to zero at equilibrium/ during a phase change?
Sun Mar 18, 2018 4:07 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: First Law
Replies: 5
Views: 654

### Re: First Law

If no heat is transferred, then q will be equal to zero. This also means that delta U will now be equal to work.
Sun Mar 18, 2018 4:05 am
Forum: Calculating Work of Expansion
Topic: Conversion of R
Replies: 7
Views: 533

### Re: Conversion of R

Check the units behind the constant R to see what needs to cancel out in the problem you are solving.
Sat Mar 17, 2018 11:07 pm
Forum: Balancing Redox Reactions
Topic: Acidic/ basic conditions
Replies: 4
Views: 388

### Acidic/ basic conditions

Other than using H+ or OH-, is there a main difference in balancing acidic vs basic reactions?
Sat Mar 17, 2018 11:04 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic/Voltaic Cells
Replies: 2
Views: 289

### Galvanic/Voltaic Cells

could someone expand on the concepts behind galvanic/voltaic cells?
Fri Mar 16, 2018 3:31 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: Microstate Determination
Replies: 2
Views: 284

### Microstate Determination

could someone explain how to calculate microstates?
Fri Mar 16, 2018 2:18 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond enthalpies to calculate change in enthalpy
Replies: 3
Views: 277

### Bond enthalpies to calculate change in enthalpy

Could someone explain how to use bond enthalpies to calculate the change in enthalpy of a reaction?
Fri Mar 16, 2018 1:22 pm
Forum: General Rate Laws
Topic: Rate Constant Units
Replies: 1
Views: 135

### Rate Constant Units

Could someone elaborate on how to find the units for different rate constants in a reaction?
Wed Mar 14, 2018 3:26 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Elementary reactions
Replies: 6
Views: 389

### Elementary reactions

could someone elaborate on elementary reactions?
Wed Mar 14, 2018 3:24 pm
Forum: *Enzyme Kinetics
Topic: Catalysts and Intermediates
Replies: 5
Views: 802

### Catalysts and Intermediates

could someone further explain the concepts for catalysts and intermediates?
Wed Mar 14, 2018 3:20 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Equation and constant
Replies: 3
Views: 253

### Arrhenius Equation and constant

could someone elaborate more on using the Arrhenius equation and its constant?
Wed Mar 14, 2018 3:16 pm
Forum: First Order Reactions
Topic: Determining Reaction Order
Replies: 5
Views: 433

### Determining Reaction Order

could someone further explain how to determine reaction orders?
Wed Mar 14, 2018 3:15 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Finding the slow step
Replies: 5
Views: 418

### Finding the slow step

How should we determine which step is the slow step?
Wed Mar 14, 2018 3:13 pm
Forum: *Alcohols
Topic: Functional group structures [ENDORSED]
Replies: 2
Views: 488

### Functional group structures[ENDORSED]

For the final do we only need to know the line structures for functional groups or should we also be able to draw the full structure?
Mon Feb 12, 2018 4:01 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Trouton's Rule
Replies: 1
Views: 153

### Trouton's Rule

Could someone explain how to apply Trouton's rule when solving for the standard enthalpy of vaporization?
Mon Feb 05, 2018 2:08 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 2nd law of thermodynamics [ENDORSED]
Replies: 1
Views: 143

### 2nd law of thermodynamics[ENDORSED]

Could someone elaborate more on the 2nd law of thermodynamics?
Mon Jan 22, 2018 10:28 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Problem 8.49
Replies: 3
Views: 246

### Problem 8.49

For this problem, how do we know to use 298K for the change in temperature in the equation?
Sun Jan 21, 2018 10:30 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Cv vs. Cp [ENDORSED]
Replies: 13
Views: 3804

### Re: Cv vs. Cp[ENDORSED]

Also to solve for the values of Cvm and Cpm you can use the equations Cvm=3/2*R and Cpm=5/2*R for the molar heat capacity.
Sun Jan 21, 2018 9:38 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.31
Replies: 3
Views: 234

### Re: 8.31

To solve part b you would start with the equation Cvm=3/2*R to get the heat capacity at constant volume. I got 12.47 J/mol for Cvm. Then you would plug in the value you got for Cvm and your other known variables into the equation q=m*C*delta T to solve for the heat released.
Sat Jan 20, 2018 7:09 pm
Forum: Phase Changes & Related Calculations
Topic: Test 1 topics
Replies: 2
Views: 237

### Test 1 topics

What homework problems will be covered on test 1?
Sat Jan 20, 2018 1:13 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Diathermic walls
Replies: 3
Views: 489

### Re: Diathermic walls

Would adiabatic walls be almost the opposite of diathermic walls?
Sat Jan 20, 2018 1:09 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: relationship between q and w
Replies: 2
Views: 193

### Re: relationship between q and w

The relationship between q and w is also affected by the change in energy of the system which can influence the signs.
Sat Jan 20, 2018 1:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard enthalpies on test 1 [ENDORSED]
Replies: 7
Views: 389

### Re: Standard enthalpies on test 1[ENDORSED]

Also, the diatomic elements all have standard states at zero.
Tue Jan 09, 2018 6:51 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Changes [ENDORSED]
Replies: 3
Views: 207

### Phase Changes[ENDORSED]

What are some important phase changes to know? (such as changes between solids/liquids/gases)
Tue Jan 09, 2018 6:47 pm
Forum: Phase Changes & Related Calculations
Topic: reversible process
Replies: 3
Views: 435

### Re: reversible process

A reversible process is when the direction can be reversed by an infinitely small change in a variable. An irreversible process is when an infinitely small change in the external pressure does not reverse the direction of travel of the piston. Also the work a system can do is the greatest in a rever...
Tue Jan 09, 2018 6:41 pm
Forum: Phase Changes & Related Calculations
Topic: Endo and Exothermic Ways to Remember
Replies: 28
Views: 5578

### Re: Endo and Exothermic Ways to Remember

Another comment on this is when you're solving for the change in enthalpy for example, a negative value for kilojoules means that the reaction was exothermic and a positive value for kilojoules means that the reaction is endothermic.
Sun Dec 10, 2017 1:18 am
Forum: Ideal Gases
Topic: Value of R
Replies: 3
Views: 1671

### Value of R

Is the value of R in PV=nRT always equal to .082?
Sun Dec 10, 2017 12:25 am
Forum: Octet Exceptions
Topic: Exceptions [ENDORSED]
Replies: 7
Views: 625

### Exceptions[ENDORSED]

When do you know that octet exceptions occur?
Sun Dec 10, 2017 12:24 am
Forum: Resonance Structures
Topic: Delocalization in Resonance Structures
Replies: 2
Views: 315

### Delocalization in Resonance Structures

For delocalization to occur, do you have to always have resonance?
Sun Dec 10, 2017 12:23 am
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidation Number
Replies: 1
Views: 233

### Oxidation Number

How do you solve for the oxidation number?
Sun Dec 10, 2017 12:22 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong or weak acids/ bases
Replies: 6
Views: 719

### Strong or weak acids/ bases

How do you determine if an acid/base is weak or strong?
Sun Dec 10, 2017 12:19 am
Forum: Lewis Acids & Bases
Topic: Determine Lewis Acid
Replies: 13
Views: 803

### Determine Lewis Acid

How do you determine if an element is a Lewis acid?
Sun Dec 10, 2017 12:16 am
Forum: Formal Charge and Oxidation Numbers
Topic: Quick Determination of FC [ENDORSED]
Replies: 6
Views: 597

### Re: Quick Determination of FC[ENDORSED]

Another quick way that I determine formal charge is:
1- counting the lone pairs around the atom (each equals 2 electrons)
2- counting the bonds around the atom (each counts as 1 electron)
Sun Dec 10, 2017 12:12 am
Forum: Dipole Moments
Topic: Dipole Occurence
Replies: 4
Views: 428

### Dipole Occurence

How do we determine when a dipole moment occurs?
Sun Dec 10, 2017 12:11 am
Forum: Sigma & Pi Bonds
Topic: Delocalization of Pi bonds
Replies: 1
Views: 268

### Delocalization of Pi bonds

How do you determine when a pi bond is delocalized?
Sun Dec 10, 2017 12:09 am
Forum: Amphoteric Compounds
Topic: Amphoteric compounds
Replies: 3
Views: 742

### Amphoteric compounds

How do you determine if a compound is amphoteric?
Thu Dec 07, 2017 6:21 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Arrhenius acids and bases
Replies: 2
Views: 253

### Arrhenius acids and bases

Will Arrhenius acids and bases be covered on the final?
Wed Dec 06, 2017 7:11 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Types and strength of Acids/Bases
Replies: 3
Views: 448

### Types and strength of Acids/Bases

Could someone elaborate on strong/ weak acids and bases and give examples for them? Also, how do we determine the type of a certain acid/base?
Sat Nov 25, 2017 8:27 pm
Forum: Dipole Moments
Topic: Dipole Moments
Replies: 3
Views: 252

### Dipole Moments

Could someone elaborate on dipole moments and how to draw them? Also, should we only draw dipole moments when the question specifically asks for them?
Sun Nov 19, 2017 6:40 pm
Forum: Sigma & Pi Bonds
Topic: drawing sigma/pi bonds
Replies: 6
Views: 424

### drawing sigma/pi bonds

How do you determine when/ where to draw sigma and pi bonds?
Sun Nov 12, 2017 12:01 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 3.5 Give the ground state configuration expected for each of the following ions:
Replies: 3
Views: 850

### Re: 3.5 Give the ground state configuration expected for each of the following ions:

You would subtract electrons from the 4p and then 4s orbitals (the outer orbitals in the configuration) before the 3d orbital.
Tue Oct 31, 2017 6:11 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 2.53 [ENDORSED]
Replies: 4
Views: 337

### Re: 2.53[ENDORSED]

Additionally, why does Se have 2 unpaired electrons instead of 4 unpaired electrons?
Tue Oct 31, 2017 6:06 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework 2.43
Replies: 4
Views: 337

### Re: Homework 2.43

For your second question, the electron configuration for tungsten is [Xe]4f^14 5d^4 6s^2 instead of [Xe]4f^14 5d^3 6s^2 because tungsten is located in the fourth space over from the start of the d block in period 6. Therefore it's noted as 5d^4 instead of 5d^3. Because the answers for the homework i...
Thu Oct 26, 2017 12:41 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Units [ENDORSED]
Replies: 4
Views: 342

### Units[ENDORSED]

When solving for the uncertainty in position, should the units be in picometers for the final answer or is it ok to leave the units in meters?
Wed Oct 18, 2017 8:02 pm
Forum: DeBroglie Equation
Topic: Wave vs Particle Properties of Light
Replies: 3
Views: 333

### Wave vs Particle Properties of Light

The Photoelectric effect shows light behaving as particles/photons. However, light is also described as having some wave-like properties. Does light behave as a combination of particles and waves or mainly as particles?
Thu Oct 12, 2017 11:32 am
Forum: Properties of Light
Topic: Prefix Conversion
Replies: 12
Views: 728

### Prefix Conversion

When converting from a prefix such as nm into meters, should the conversion be before or after we solve the problem?
Tue Oct 03, 2017 2:40 pm
Forum: Significant Figures
Topic: All students read this sig fig post [ENDORSED]
Replies: 131
Views: 16915

### Re: All students read this sig fig post[ENDORSED]

I believe we use a sig fig rule each time we do a calculation. For addition/ subtraction, the number of decimal places in the answer should have the smallest number of decimal places from the number being added/ subtracted. Example: 112.2+60.23= 172.4 . For multiplication/ division, the number with ...

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