CHEMISTRY COMMUNITY

Patrick Ricaflanca 2H

Dr. Lavelle, Although I still can't say chemistry is my favorite subject, I really think having you as a teacher really challenged me to think analytically and problem solve. I appreciate the positive attitude you project in lectures and how you provide all these resources for your students. It has ...

Patrick Ricaflanca 2H

My TA told me that the class would focus more on exergonic reactions. So when they tell us to draw the reaction profiles, they would also tell us if the reaction was exergonic or endergonic. If it's exergonic, the reactants start off higher than the products, and if endergonic vice versa.

Patrick Ricaflanca 2H

I think if you're having trouble identifying the parent chain, you can just count all the C's outside the parentheses, then consider the one in parentheses the subsituent of the adjacent C atom.

Patrick Ricaflanca 2H

I was also thinking the same thing: whether it can be written as CH3-CHBr-CH3 as opposed to CH3-CH2-CH2Br.

Patrick Ricaflanca 2H

I think we might have to use the first order equation: ln(k2/k1)=Ea/R * ((1/T1)-(1/T2)). Maybe first solving for Ea, then using the equation again to solve for k2 at 770 K.

Patrick Ricaflanca 2H

I think the answer should be the same even if you used the one with 'ln' instead of 'log'. But then instead, it would be 0.02568/n when you plug it into the Nernst equation: {Ecell= Escp - (0.02568/n)*lnQ}

Patrick Ricaflanca 2H

I think it may have something to do with entropy being a state function. So if the reaction returns to the same state it was in before, then there was no change.

Patrick Ricaflanca 2H

Also, I think it would require more energy to break the double bond than it would be to break the single bond (if you want to say something in terms of energy).

Patrick Ricaflanca 2H

I think most of what will be asked for is the manipulation of given equations to solve for problems.
For example, delta U= q+w; since w=-PV we can substitute it into the equation -> delta U= q - PV

Patrick Ricaflanca 2H

Since a bond is being formed, energy is being released from the system and the enthalpy of that part of the system would be negative.
In the case where a bond is being broken, energy is being taken up by the system to break a bond and the enthalpy of that part of the system would be positive.

Patrick Ricaflanca 2H

I think you can use the equation [q= m* Csp *(delta T)], where m is mass in grams, to find the "specific heat capacity".

Patrick Ricaflanca 2H

If given a list of molecules, how would you determine which has the highest dipole moment? (Assuming they all have dipole moments)

Patrick Ricaflanca 2H

The longer the bond, the stronger the acid; for example this order from weakest to strongest acids:
H-F < H-Cl < H-Br < H-I

Patrick Ricaflanca 2H

Is there a way to identify whether something is mono-, bi-, try-, etc. dentate just by looking at the compound given? Or do we always have to draw the structure?

Patrick Ricaflanca 2H

I think we should know the structure of the coordination compound if we were asked about the dentisity of the compound (eg. the polydentate: EDTA)

Patrick Ricaflanca 2H

So is there a quick way to determine the order of ionic/covalent characteristics just by looking at the periodic table? The closer two elements are to each other in a molecule on the periodic table, the more covalent they are. The farther they are from each other on the periodic table, the more ioni...

Patrick Ricaflanca 2H

Since Xenon can be considered a central atom, does that mean Krypton and Radon can also act as the central atom?

Patrick Ricaflanca 2H

The central atom should be the one with the least electronegativity. From left to right on the periodic table, electronegativity increases. From top to bottom, electronegativity decreases. So for a) sulfite ion, the sulfur ion would be in the middle and connected to 3 oxygens. Even though they are i...

Patrick Ricaflanca 2H

Plus, in my opinion, showing work helps make sure you're on the right track, like having the correct units for your numbers and also having the right amount of sig figs in the end.

Patrick Ricaflanca 2H

Yeah. I think Professor Lavelle just meant 10^15 was the general cutoff point to determine if a wavelength is measurable. Like if a question were to ask whether an object with a certain mass and velocity has a measurable wavelength, 10^15 would be the cutoff. >10^15 meaning it is, and <10^15 meaning...

Patrick Ricaflanca 2H

This is an example we did in our discussion session, if you find it helpful. Ex. Caffeine is 49.48% C, 5.19% H, 16.4% O, and 28.61% N. Find the empirical formula. 1. First, we had to assume it was over 100 g so that we could get rid of the percentages and make them into grams. 2. Then we divide each...

CHEMISTRY COMMUNITY

Search found 21 matches

Re: Saying Thank You to Dr. Lavelle

Re: Drawing/Labeling reaction profile

Re: Alkane name

Re: Electrophilic addition reaction of HBr and Propene

Re: Quiz 2 Practice Question 11

Re: .05916 In Nernst Equation

Re: Entropy - Reversible vs Irreversible

Re: Bond Enthalpies

Re: Derivations

Re: Enthalpy [ENDORSED]

Re: Calculating the Heat Given Off By a Reaction

Re: Dipole and Polarity [ENDORSED]

Re: strong or weak acid

Re: Identifying Polydentates? [ENDORSED]

Re: Shape of coordination compound

Re: Covalent and Ionic Character

Noble Gas as central atom

Re: Chapter 3 #57 [ENDORSED]

Re: Showing Work [ENDORSED]

Re: Worked Example on page 52 in the Course Reader

Re: Calculating Molecular and Empirica Formulas