Search found 29 matches
- Thu Mar 15, 2018 7:52 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Cell Potential
- Replies: 9
- Views: 3183
Re: Cell Potential
They're the same, you can use either
- Thu Mar 15, 2018 7:48 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: mass in q = m(c) delta t
- Replies: 5
- Views: 892
Re: mass in q = m(c) delta t
Specific heat capacity uses grams while Molar heat capacity uses moles
- Thu Mar 15, 2018 7:45 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Units
- Replies: 3
- Views: 632
Re: Units
The units are in KJ/mol but KJ alone should also be ok
- Thu Mar 15, 2018 7:44 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: What does R stand for?
- Replies: 13
- Views: 3311
Re: What does R stand for?
R is the ideal gas constant.
- Thu Mar 15, 2018 7:41 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2949222
Re: Post All Chemistry Jokes Here
A photon checks into a hotel and is asked if he needs any help with his luggage. He says, "No, I'm traveling light."
- Thu Mar 15, 2018 7:38 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2949222
Re: Post All Chemistry Jokes Here
Have you heard the one about a chemist who was reading a book about helium?
He just couldn't put it down.
He just couldn't put it down.
- Thu Mar 15, 2018 7:36 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2949222
Re: Post All Chemistry Jokes Here
How often does a chemist like to hear jokes? Periodically.
- Thu Mar 15, 2018 7:36 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2949222
Re: Post All Chemistry Jokes Here
Electron configuration? How BOHRing.
- Thu Mar 15, 2018 7:35 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2949222
Re: Post All Chemistry Jokes Here
Have you heard about Agent 007 going to Antarctica? It was a polar Bond.
- Thu Mar 15, 2018 7:31 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Is enthalpy a state function?
- Replies: 12
- Views: 2174
Re: Is enthalpy a state function?
Yes, it is
- Thu Mar 15, 2018 7:30 pm
- Forum: Phase Changes & Related Calculations
- Topic: U = 3/2 nRT
- Replies: 3
- Views: 2035
Re: U = 3/2 nRT
I don't think you will have to answer a question using that equation, but like the answer above states, it's helpful to see the relationship between U and T (the only nonconstants in the equation).
- Thu Mar 15, 2018 7:28 pm
- Forum: Phase Changes & Related Calculations
- Topic: Reversible
- Replies: 5
- Views: 1091
Re: Reversible
The reversible expansion does not have constant pressure, while the irreversible one does.
- Thu Mar 15, 2018 7:27 pm
- Forum: Phase Changes & Related Calculations
- Topic: Environmental impact?
- Replies: 6
- Views: 1001
Re: Environmental impact?
I don't think so, I think there were only be system/surroundings stuff that relate to the environment.
- Mon Feb 12, 2018 7:03 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Cv vs. Cp [ENDORSED]
- Replies: 13
- Views: 11727
Re: Cv vs. Cp [ENDORSED]
Cv-is when there's constant volume and Cp-is when there's constant pressure.
- Mon Feb 12, 2018 7:00 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Sublimation
- Replies: 3
- Views: 503
Re: Sublimation
Enthalpy of Sublimation (solid to gas) is the sum of enthalpy of fusion and enthalpy of vaporization
- Mon Feb 12, 2018 6:57 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Equations
- Replies: 4
- Views: 780
Equations
Does anyone know if we have to memorize all of the equations that are not on the Constants and Equations sheet?
- Sun Feb 04, 2018 10:03 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat capacity [ENDORSED]
- Replies: 4
- Views: 509
Re: Heat capacity [ENDORSED]
No, I am assuming Professor Lavelle is proving those
- Sun Feb 04, 2018 10:02 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Different Changes in Enthalpy symbols -ΔH
- Replies: 3
- Views: 1053
Re: Different Changes in Enthalpy symbols -ΔH
ΔHc-enthalpy of combustion; ΔHL-lattice enthalpy; ΔHb is bond enthalpy.
- Sun Feb 04, 2018 10:01 pm
- Forum: Phase Changes & Related Calculations
- Topic: The universe
- Replies: 9
- Views: 1053
Re: The universe
Because no energy or matter can be transferred
- Sun Feb 04, 2018 9:59 pm
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy vs. Entropy
- Replies: 4
- Views: 520
Re: Enthalpy vs. Entropy
Entropy is a measure of disorder or randomness of a system. Enthalpy is defined as the sum of internal energy of a system and the product of the pressure and volume of the system.
- Sun Jan 28, 2018 2:53 pm
- Forum: Phase Changes & Related Calculations
- Topic: Heat and Work relation
- Replies: 6
- Views: 712
Re: Heat and Work relation
No, the work doesn't necessarily have to be negative in this case.
- Sun Jan 28, 2018 2:52 pm
- Forum: Phase Changes & Related Calculations
- Topic: Closed Systems [ENDORSED]
- Replies: 8
- Views: 1167
Re: Closed Systems [ENDORSED]
Because energy is transferred in closed systems, adding or subtracting heat will affect the energy.
- Sun Jan 28, 2018 2:49 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Question 8.31
- Replies: 7
- Views: 1011
Re: Question 8.31
You can use either because adding 273 won't make a difference.
- Sun Jan 21, 2018 9:07 pm
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 415714
Re: Rusty on High School Chem [ENDORSED]
I took chem 14a last quarter and I never took AP Chem in high school. Watching youtube videos on concepts I didn't understand really helped me.
- Sun Jan 21, 2018 9:04 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hesss Law
- Replies: 6
- Views: 534
Re: Hesss Law
Yes, you will need to know these three techniques: Hess's law, Bond Enthalpies, Standard enthalpies of formation. The only one you don't have to worry about for the test is isothermal.
- Sun Jan 21, 2018 9:01 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Week 3 Test Topic is endorsed
- Replies: 37
- Views: 4737
Re: Week 3 Test Topic is endorsed
Does Dr. Lavelle only test on things he's talked about?
- Mon Jan 15, 2018 12:43 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law
- Replies: 3
- Views: 353
Hess's Law
What does Hess's law allow you to do?
- Mon Jan 15, 2018 12:42 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy
- Replies: 2
- Views: 312
Enthalpy
Given a forward reaction with positive enthalpy, will its reverse reaction be endothermic or exothermic?
- Mon Jan 15, 2018 12:36 am
- Forum: Limiting Reactant Calculations
- Topic: Reactant vs. Reagent [ENDORSED]
- Replies: 23
- Views: 34391
Re: Reactant vs. Reagent [ENDORSED]
reactant: A substance participating in a chemical reaction, especially a directly reacting substance present at the initiation of the reaction.
reagent: A substance used in a chemical reaction to detect, measure, examine, or produce other substances.
reagent: A substance used in a chemical reaction to detect, measure, examine, or produce other substances.