Search found 30 matches
- Mon Mar 12, 2018 10:08 pm
- Forum: *Enzyme Kinetics
- Topic: Catalyst
- Replies: 6
- Views: 897
Re: Catalyst
Catalysts are enzymes; they are "recycled." So look for the substance that appears as a reactant in the first step of a reaction, and the reappears later as a product.
- Mon Mar 05, 2018 9:50 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2991534
Re: Post All Chemistry Jokes Here
Q; How does sulfer communicate with other elements?
A: A sulfone.
A: A sulfone.
- Mon Mar 05, 2018 9:48 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2991534
Re: Post All Chemistry Jokes Here
A neutron walks into a shop and says,"I"d like a coke."
The shopkeeper serves up the coke.
"How much will that be?" asks the neutron.
The shopkeeper replies, "For you? No charge."
The shopkeeper serves up the coke.
"How much will that be?" asks the neutron.
The shopkeeper replies, "For you? No charge."
- Mon Mar 05, 2018 9:47 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2991534
Re: Post All Chemistry Jokes Here
Why does hamburger yield lower energy than steak?
Because it's in the ground state.
Because it's in the ground state.
- Mon Mar 05, 2018 9:40 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2991534
Re: Post All Chemistry Jokes Here
I asked the guy next to me if he had any sodium hypobromite. He said NaBrO.
- Mon Mar 05, 2018 9:40 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2991534
Re: Post All Chemistry Jokes Here
Why was the mole of oxygen molecules excited when he left the singles bar?
He got Avogadro's number!
He got Avogadro's number!
- Mon Mar 05, 2018 9:36 pm
- Forum: General Rate Laws
- Topic: rate of change of species
- Replies: 2
- Views: 361
Re: rate of change of species
to add onto the previous reply, that is why unique rates are formatted the way they are. coefficients are incorporated
- Sun Feb 25, 2018 9:26 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2991534
Re: Post All Chemistry Jokes Here
how to tell the difference between a plumber and a chemist: ask them to pronounce the word "unionized"
- Sun Feb 25, 2018 9:23 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2991534
Re: Post All Chemistry Jokes Here
If I had a choice between DNA and RNA, I'd choose RNA because it has U in it.
- Sun Feb 25, 2018 9:21 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2991534
Re: Post All Chemistry Jokes Here
Did you hear about the galvanic cell that went to court?
He got charged with a salt and battery!
He got charged with a salt and battery!
- Sun Feb 18, 2018 11:24 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electromotive force and Why is E a Maximum
- Replies: 2
- Views: 372
Re: Electromotive force and Why is E a Maximum
The book calls it a hidden assumption, but basically know that the cell is operating reversibley, so the potential difference calculated is the maximum source of potential that can be produced. The equation for Ecell only works when the pushing power of the cell is balanced against an external match...
- Sun Feb 18, 2018 11:16 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Exercise 14.31
- Replies: 2
- Views: 395
Re: Exercise 14.31
to add onto the previous reply, if you don't want to think of it solely in terms of spontaneity, you could also infer that K>1 because Ecell>0, which means products are favored, and this is due to the relationship between E and K, as seen in the equation derived in section 4.8
- Sun Feb 18, 2018 11:11 pm
- Forum: Balancing Redox Reactions
- Topic: Exercise 14.17
- Replies: 6
- Views: 757
Re: Exercise 14.17
Th toolboxes on 563 and 575 are helpful!
- Sun Feb 11, 2018 3:32 pm
- Forum: Balancing Redox Reactions
- Topic: E cell potiential
- Replies: 2
- Views: 278
Re: E cell potiential
cant confirm but I want to say yes. in lecture dr lavelle said its the balancing coefficient of both the reduction and oxidation half reactions, and that they are they same number. makes sense because electrons are conserved in redox rxns
- Sun Feb 11, 2018 3:20 pm
- Forum: Balancing Redox Reactions
- Topic: Reduction and Oxidation
- Replies: 4
- Views: 484
Re: Reduction and Oxidation
I assume you mean oxidation number/state. When it increases, the element is being oxidized, and when it decreases, reduced.
- Sun Feb 11, 2018 3:18 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: unit of standard reduction potential
- Replies: 2
- Views: 312
Re: unit of standard reduction potential
you can also use the following equation to help you remeber: E= -w/charge, where work done is in joules, and charge is in coulombs. J/C is V (volts)
- Sun Feb 11, 2018 3:07 pm
- Forum: Balancing Redox Reactions
- Topic: 14.5
- Replies: 3
- Views: 568
Re: 14.5
The reason O2's oxidation number is 0 is that oxidation states of atoms in their elemental states is zero. Oxygen gas is diatomic, often found in nature as O2, so that is why its oxidation number is zero. The same cannot be said for O3 however, and its oxidation number is -6 (3 x 2 O's)
- Fri Feb 02, 2018 10:41 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Calculation methods
- Replies: 3
- Views: 463
Re: Calculation methods
It would make sense seeing as they as both state functions so you're probably right!
- Fri Feb 02, 2018 10:37 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Micro states
- Replies: 5
- Views: 625
Re: Micro states
number the many possible positions molecules can be arranged in in a system. #possible states^#particles=degeneracy (W)
- Fri Feb 02, 2018 9:43 am
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy vs. Entropy
- Replies: 4
- Views: 520
Re: Enthalpy vs. Entropy
Enthalpy can be measured quantitatively because of processes like calorimetry. It is essentially heat, and we use temperature to measure it directly. Entropy is the measure of how disordered a system is, so it is harder to give it a number value, however; the equation S=kblnW allows you to calculate...
- Sun Jan 28, 2018 6:05 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: Gas atoms
- Replies: 4
- Views: 490
Re: Gas atoms
Another way to think about it is how gases behave logically. They're not going to ever want to revert to a state where they have less space/freedom to move around. And a generally good rule of thumb is that gases are always going to want to go to a state of increased entropy, as explained in the pre...
- Sun Jan 28, 2018 6:02 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Spontineity
- Replies: 5
- Views: 679
Re: Spontineity
You can think of a spontaneous reaction as something that occurs on its own, without an external nudge, i.e. an input of energy. A reaction that requires an input of energy does not occur on its own, and is therefore not "spontaneous."
- Sun Jan 28, 2018 5:59 pm
- Forum: Calculating Work of Expansion
- Topic: The integral equation
- Replies: 8
- Views: 697
Re: The integral equation
The equation is similar when dealing with pressure right? Except it's Pinital/Pfinal because of the inversely proportional relationship between P and V?
- Sun Jan 21, 2018 8:31 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Heat versus work
- Replies: 6
- Views: 798
Re: Heat versus work
From the textbook: "The fundamental molecular difference between work and heat is related to the orderliness with which atoms in the surroundings move. When energy is transferred as work, the system moves molecules in the surroundings in a definite direction... During the transfer of energy as ...
- Sun Jan 21, 2018 8:24 pm
- Forum: Calculating Work of Expansion
- Topic: What do these variables mean?
- Replies: 4
- Views: 459
Re: What do these variables mean?
Those are right! Also in the last step, AD turns into deltV (change in volume) because it is referring to area x distance (height). Page 263 of the textbook has diagrams that demonstrate this series of equations.
- Sun Jan 21, 2018 8:14 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Possible Error in Question 8.55 (Hess' Law)
- Replies: 4
- Views: 497
Re: Possible Error in Question 8.55 (Hess' Law)
Chris Lamb 1G wrote:[quote="Marina Georgies 1C" Sidenote- where is Dr. Lavelle's list of errors posted? I can't seem to remember.
It is a PDF on the 14B page titled "Solution Manual Errors"
Here it is:https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14B/Solution_Manual_Errors_6Ed.pdf[/quote]
Thankyou!!!!
- Sun Jan 21, 2018 8:13 pm
- Forum: Calculating Work of Expansion
- Topic: Reversible vs Irreversible
- Replies: 4
- Views: 488
Re: Reversible vs Irreversible
I may be wrong but I believe you are referring to irreversible vs reversible processes. A reversible process can be reversed by infinitely small changes in a variable (such as volume), and these infinitesimal changes are so tiny that they result in the maximum amount of work done. In the end, though...
- Sat Jan 13, 2018 8:28 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Sig Figs for Question 8.45 (a)
- Replies: 5
- Views: 509
Re: Sig Figs for Question 8.45 (a)
Although most math classes teach the rule that .5 or 5 rounds up, another commonly accepted method is to round to the nearest even number. I think the method of rounding commonly used in chemistry is the second one, as mentioned in the previous replies. So they are correct about rounding a 5 or .5 t...
- Sat Jan 13, 2018 8:17 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Possible Error in Question 8.55 (Hess' Law)
- Replies: 4
- Views: 497
Re: Possible Error in Question 8.55 (Hess' Law)
I keep running into the same problem with this question, and I also believe it could be an error. Sidenote- where is Dr. Lavelle's list of errors posted? I can't seem to remember.
- Sat Jan 13, 2018 8:10 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: systems [ENDORSED]
- Replies: 5
- Views: 511
Re: systems [ENDORSED]
It's really easy to confuse isolated and closed systems but the key in this example is to recognize that the mercury is affected by the temperature outside, so there there is an exchange of energy in the form of heat between the contents of the system (mercury) and the surroundings.