CHEMISTRY COMMUNITY

Ethan Frankel 2C

Professor Lavelle said that they will accept either J/mol or kJ/mol for enthalpy and entropy. I believe Gibbs is generally kJ/mol, but as long as the conversions are correct and the units are generally consistent, you should be fine. Hope that helps!

Ethan Frankel 2C

Since the Nernst equation is E = E°- (RT/nF)lnQ and T will be at standard conditions, R, T, and F are all constants. The solution just combines these to acquire .05916/n. This is also an equation that is provided on the equation sheet. Hope that helps!

Ethan Frankel 2C

In class, Dr. Lavelle stated that there were cyclic compounds that ranged from 3 to 30 carbon atoms, but the ones that are most stable contain 5 or 6 carbons. Therefore, I'm sure there's some limit to how many carbon atoms make a stable structure, but as for that actual number, I'm not sure. Hope th...

Ethan Frankel 2C

Yep, you can use the pre-equilibrium approach for both.

Ethan Frankel 2C

Professor Lavelle derived half-life reaction laws during one lecture a week or so ago. On page 66 and 67 of the course reader, the half-life equations are provided: second order is t1/2 = 1/k[A]o and zero order is t1/2 = [A]o/2k. Since there's only one reactant, both zero order and second order reac...

Ethan Frankel 2C

Yep! The reactant/cathode will be the higher concentration, and the lower concentration is the anode. Can you explain why this is so? The electrons will flow from the cell with lower concentration (anode) because the solid electrode releases its cations into solution, therefore increasing concentra...

Ethan Frankel 2C

Yep! The reactant/cathode will be the higher concentration, and the lower concentration is the anode.

Ethan Frankel 2C

Voltage is an intensive property, meaning the amount of reactions that occur doesn’t change the amount of voltage. Therefore, the value of the voltage doesn’t change, the only part of voltage that changes is the sign if the reaction is reversed. Hope that helps!

Ethan Frankel 2C

The purpose of a salt bridge is to keep the solutions in both the anode and cathode neutral. When the electrons flow from the anode to cathode, the solution on the cathode side will become more negative, as the anode solution will become more positive. If there were no salt bridge, the electrons wou...

Ethan Frankel 2C

A reversible process is one in equilibrium, meaning it occurs in incredibly small steps or changes. Therefore, the process can be reversed at any point without much effort. Irreversible processes are large or sudden changes and therefore cannot be reversed. For what we have been working on, work per...

Ethan Frankel 2C

Firstly, there actually aren’t any H—H bonds in either of these compounds (all of the hydrogen molecules are bonded to carbon with a single bond). As for why the C—H bonds aren’t part of the solution, going from the reactant to product, C—H bonds aren’t formed during the reaction since they already ...

Ethan Frankel 2C

Hi! If the K value that is initially given is less than 10-4, then you can assume that x will be less than 5% and therefore do not have to use the quadratic equation. However, if K=10-4 you have to check (and if it’s greater, you have to use the quadratic equation). To check, you simply perform the ...

Ethan Frankel 2C

Since ethylenediamine is a bidentate, the N on NH2 binds to the transition metal. It also forms a bond with carbon (the ethylene), so therefore fulfills the octet rule. I think that's why the amine only has two H's instead of three.

Ethan Frankel 2C

They're both equilibrium constants and can be used for gases, but Kc is for concentrations (molarity) while Kp is partial pressures. The method for finding them is both the same. Hope that helps!

Ethan Frankel 2C

I think we are supposed to memorize them all including names and formulas.

Ethan Frankel 2C

Ionic character (and covalent character) refers to the difference in electronegativity. The greater the difference in electronegativity between atoms, the greater ionic character the bonds will be, and the closer the electronegativity is between the two atoms, the more covalent. For example, with Na...

Ethan Frankel 2C

After performing the first steps of adding valence electrons and drawing the initial Lewis structure, the formal charge is what makes it either a triple or double bond. This is a good website for rules on Lewis structures: http://chemistry.umeche.maine.edu/CHY251/therules.html
Hope that helps!

Ethan Frankel 2C

The roman numeral represents the charge. Cu(II) is also Cu2+

Ethan Frankel 2C

486 is the wavelength in nm. When you compare that to Table 1.1 (on page 4), it is closest to 470 nm, which is blue visible light.

Ethan Frankel 2C

Yes, the t means metric tons (1 t=1000 kg). After solving for the grams of NaBr, convert to moles and work backwards just like you said!

CHEMISTRY COMMUNITY

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Re: Units for dG

Re: Winter 2013 Final Q3C

Re: Cyclic Maximum

Re: Pre-equilibrium Approach

Re: Quiz 2 Prep (#7 from Winter 2016)

Re: midterm 2015 Q7

Re: midterm 2015 Q7

Re: Balancing Redox equations [ENDORSED]

Re: Salt Bridge In Galvanic Cells?

Re: Reversible Reactions

Re: Problem 8.73 a

Re: Approximating X

Re: Ethylenediamine

Re: Kc or Kp

Re: Memorizing Ligands?

Re: Quiz 2 Question 1 Wording [ENDORSED]

Re: Double and Triple Bonds

Re: Ionic Chemical Equation

Re: Ch.1 #13

Re: L.35 Homework Question