CHEMISTRY COMMUNITY

Blake_Katsev_2E

will there be a homework question on this exam?

Blake_Katsev_2E

i calculated it and i got different results

Blake_Katsev_2E

On question 7B, what makes a cyclohexene with two substituents trans or cis? is it because of one being axial and one being equitorial?

Blake_Katsev_2E

For student B in problem four, how would you write the rate law because there are two intermediates? do you need to cancel out the O2's on each side to make it only have one intermediate or is there another method?

Blake_Katsev_2E

Hi on question 3 C, with the reaction 2Ag+Br2-->2AgBr, why would the cell diagram have AgBr(s) on the anode side? i know that Ag is going to Ag+ but how/why would the bromine attach? Arent they in separate locations? I know that it would be AgBr as a product but do they actually come and fuse togeth...

Blake_Katsev_2E

Why in question 2A when the question says that each of the two reactants have half of the partial pressure as the single product would the K=2x/x^2 rather than K=x/(x/2)^2

Blake_Katsev_2E

Is 13456-pentahydroxy-2-hexanone saying the same thing as hexan-2-one-13456-pentol?

Blake_Katsev_2E

thanks!

Blake_Katsev_2E

How in this question, when using the NERST equation, would you know what to put in the numerator and denominator of ln? Also how would you know that there is only one mole? This question involves the concentration of K ions on the outside and inside of a membrane.

Blake_Katsev_2E

Why would there be 3 sig figs in the answer if the question had 25 degrees C and 47 degrees C?

Blake_Katsev_2E

as in hexadecanol, i dont recall learning how to draw these particular structures.

Blake_Katsev_2E

Do we need to know how to do question 6B/how do we do it?

Blake_Katsev_2E

on question 4C, how does the rate become positive? Also in part B of it do you assume that Q is equal to 1/[02] because it is the only aqueous molecule?

Blake_Katsev_2E

Do we need to know common names because some problems assigned ask us for the common and the IUPAC but we havnt really gone over how to use common names with functional groups and common names just in general. Also what is the functional group name of a double and triple bond?

Blake_Katsev_2E

Why on question 2.40 would it be 2-methylbut-3-yn-2-ol rather than making it a 3 carbon chain with two methyls to lower all the numbers by one? like making it 1,1-dimethylprop-2-yn-1-ol.

Blake_Katsev_2E

What is an ambident nucleophile?

Blake_Katsev_2E

Why would this be an electrophile? it has a double bond around the N right? so that means a lot of electron density

Blake_Katsev_2E

In question 1.16 there is a pentane ring with a isopropyl and dimethyl substituent. Shouldn't the isopropyl be 1 and dimethyl be on Carbon two? They are both either 1 or 2 so i thought you would go alphabetically

Blake_Katsev_2E

At the end of class today professor Lavelle described how (CH3)2O is a nucleophile due to the oxygens lone pairs. But for CH3O, the carbon is now an electrophile because the C now gets the full pull of Oxygens pulling power. So C is an electrophile but wouldn't that make O a nucleophile? I am confus...

Blake_Katsev_2E

What is the difference between a constitutional isomer and a geometric isomer? What are some examples of each?

Blake_Katsev_2E

Shouldnt number 4 be 5-butyl instead of 4-butyl?

Blake_Katsev_2E

Are we supposed to already know how to do cis, Z and trans, E organic structures? Because these problems are assigned but were never gone over in class.

Blake_Katsev_2E

Hi two part question. Is the numbering of the carbon atoms in this question arbitrary? So could the isopropyl also be 1-isopropyl and the methyls both be on the second carbon or does it have to be isopropyl 1 and dimethyl two? And when ordering the name would you go alphabetically by propyl or does ...

Blake_Katsev_2E

part m. How do you determine if something is kinetically controlled or thermodynamically controlled? It seems like the reactions with the higher activation energies are kinetically controlled but it seems it should be the opposite because it should be harder for the process to happen

Blake_Katsev_2E

it says that the activation energy is 125 kj/mol, how do you know if it will occur at room temperature?

Blake_Katsev_2E

so would that mean when the energy of products is less, raising the temperature would always lower K?

Blake_Katsev_2E

Im sorry but part b to this question just makes no sense, can somebody explain it in other words? thanks

Blake_Katsev_2E

Don't catalysts increase both k and k'? So why would we use them if they are both increased because it seems like that wouldn't change anything. Like in step d of 15.74, wouldn't the catalysts be chosen to shift the equilibrium towards the products?

Blake_Katsev_2E

If given these three steps, how do you know wht the activation energies of each will be and if the overall is exothermic when graphing the process?

Blake_Katsev_2E

can somebody explain the math behind 15.69

Blake_Katsev_2E

Why in the solutions manual do they do (T'-T/T'*T) for the arrhenius equation?

Blake_Katsev_2E

why would raising temperature affect k more rather than k' if the activation energy of k is higher?

Blake_Katsev_2E

Could somebody explain why graphing the half life vs. concentration of a zero order reaction is linear but not if its second order?

Blake_Katsev_2E

Will we need to know this for the quiz?

Blake_Katsev_2E

How would we determine the rate law if the first step is slow but there is an intermediate as a reactant? As in if a reactant is later formed so that they would cancel out?

Blake_Katsev_2E

How would water be put in the rate law? Because wouldn't the concentration only be one at all times? What should we include in rate laws? Only gasses and aqueos solutions or what?

Blake_Katsev_2E

For this question in the textbook could somebody please give a detailed answer because the solutions manual doesn't have that. Like what does it mean to graph the half life vs. [A]?

Blake_Katsev_2E

9.47 Initially a sample of ideal gas at 323 K occupies 1.67 L at 4.95 atm. The gas is allowed to expand to 7.33 L by two pathways: (a) isothermal, reversible expansion; (b) isothermal, irreversible free expansion. Calculate "Stot, "S, and "Ssurr for each pathway. I understand when cal...

Blake_Katsev_2E

A voltaic cell functions only when the electrical circuit is complete. In the external circuit the current is carried by the f ow of electrons through a metal wire. Explain how the current is carried through the cell itself. the answer is a negativley charged electrolyte goes from cathode to anode, ...

Blake_Katsev_2E

How would Volta have ordered the following metals, if he put the most
strongly reducing metal f rst: Fe, Ag, Au, Zn, Cu, Ni, Co, Al?

Why would they be ordered from lowest to highest reduction potentials? Shouldnt a higher potential mean stronger reducing power of the metal?

Blake_Katsev_2E

Does anybody know what the right answer was to the question about two crystals at 0K? it said that there was one crystal of CO and N2, and asked which would have a higher entropy.

Blake_Katsev_2E

Why in question 14.83 does the answer say that they are both temperature dependent? isn't E not only valid at one temperature?

Blake_Katsev_2E

Thank you that helped out a lot. But still a little confused on the square root part^

Blake_Katsev_2E

in question 6 there is double rounding which changes the final answer, so what should we do in this instance and what will be get points for doing? @lavelledoggydog

Blake_Katsev_2E

Why on question 4 part D why would you need to find the entropy change of water going to the boiling point and entropy change of the phase change, AND the entropy change of going back to the original temperature? i dont understand what is going on conceptually here.

Blake_Katsev_2E

Why on question 5.b would the Cv be used rather than Cp because the balloon is expanding?

Blake_Katsev_2E

No they arent very close together...

Blake_Katsev_2E

Why in question 8 would the first rxn be oxidized? dont you want a positive cell potential? and also how do you get from K to Ka and what does Ka mean in this context?

Blake_Katsev_2E

why on question 5c would E be considered a path function?

Blake_Katsev_2E

Why in question 7 are they using (0.05916/n)*logQ rather than (0.02569/n)*lnQ?

Blake_Katsev_2E

Why in question 5B would the entropy only be decided by the size of the molecules? Shouldnt there be more entropy if it has more possible arrangements?

Blake_Katsev_2E

Why on question 1a would you need to break two O-H bonds rather than the one that is connected to the oxygen that leaves the molecule? so would would you break and reform it? i understand if its a double bond that you need to break both then reform one but im not sure about this case.

Blake_Katsev_2E

Why in question 15.35 would you not be able to multiply the half live time by 4 to see how long it takes to get to one 16th its original concentration?

Blake_Katsev_2E

When going from a gas to a liquid is deltaH positive or negative and why?

Blake_Katsev_2E

Why would Enot be temperature dependent? I thought it would always be at 25 C. It says it is for 14.83

Blake_Katsev_2E

Why in 14.57 would water have an Enot value of 0.42? thats not in the back of the book

Blake_Katsev_2E

Why in question 14.55 would the SO4 not oxidize and use the electrolysis of water instead?

Blake_Katsev_2E

When do you need to add platnium to the cell diagram? if its a gas? if its a liquid? if its a noncunducting metal? which elements do you not need it for?

Blake_Katsev_2E

why on 14.15 would the cell diagram be labeled as it is? Why would Ag be on both sides and why would AgBr be on the reduction part?

Blake_Katsev_2E

What is the differences between Gibbs free energy and standard gibbs free energy and when do you use each?

Blake_Katsev_2E

Why when calculating K, is there only one sig fig?

Blake_Katsev_2E

can we always use the two ways of calculating delta G or are there limitations to using them?

Blake_Katsev_2E

so i would find the change in moles and use delta n*R*T for work to add to enthalpy

Blake_Katsev_2E

What would happen in a process that is irreversable and reversible but not isothermal? or do we not need to know that?

Blake_Katsev_2E

Why in this problem would there be a net production of 2/3 mole of gas?

Blake_Katsev_2E

Why is there no work done in free expansion? and does free expansion mean irreversible?

Blake_Katsev_2E

How is this conversion factor acquired?

Blake_Katsev_2E

is the equation for work done in an isothermal process w=-nRT(V2/V1) or -nRTln(V2/V1)

Blake_Katsev_2E

When would you use Hc and when would you use Hf?

Blake_Katsev_2E

How do you know when to flip an equation or halve or double it?

Blake_Katsev_2E

Why in this question in the textbook is the second equation halved?

Blake_Katsev_2E

When a weak acid or base is being titrated but not all of the original amount of moles is not used up so there is extra. How do you know when to have it act as its conjugate base or acid because there is some of its concentration as a reactant (base) as well as product (conjugate acid).

Blake_Katsev_2E

why when adding HCl does acid concentration go up AND base concentration go down?

Blake_Katsev_2E

will a d orbital electron ever be ejected before an S orbital one?

Blake_Katsev_2E

Why would the 3 H's have more electron pulling power than 3 CH3s?

Blake_Katsev_2E

Shouldnt Cl2 come before NH3 because c comes before N in the alphabet?

Blake_Katsev_2E

Why would IF5 be polar? is it because of the electrons on the central atom?

Blake_Katsev_2E

why would AgF be more ionic than Be(Cl)2?

Blake_Katsev_2E

will a D orbital e- of n-1 ever be removed before a Sn?

Blake_Katsev_2E

So a small positively charged cation has strong polarizing power, what makes an anion polarizable?

Blake_Katsev_2E

why in question 8 is there only 3 sig figs?

Blake_Katsev_2E

Why is Mg(OH)2 and Be(OH)2 not strong bases? the heavier alkaline ones are though.

Blake_Katsev_2E

How does the molecular orbital theory relate to hybridization? because shouldn't there be hybridization if to molecules are bonding? Also what purpose does the MOB serve? To show all of the electron bonds?

Blake_Katsev_2E

Why would adding NaOH to the reaction : CH3COOH + H2O --> CH3CO2- + H3O+ create more CH3CO2- and decrease the amount of CH3COOH?

Blake_Katsev_2E

Why when writing K do you use (Kb x Ka)/Kw?

Blake_Katsev_2E

why when finding the Ka would the denominator be (1-.024) x .110 rather than being .11-.00264 which the ice box indicates that it should be.

Blake_Katsev_2E

why would 2,4,6 trichlorophenol be a stronger acid than phenol? is it because the chlorine atoms are very electronegative and thus is better with a negative sign so it can lose a proton easily?

Blake_Katsev_2E

why would CH3COOH + NH3 --> CH3CONH2 +H20 not be considered a bronsted base with no proton transfer?

Blake_Katsev_2E

When dealing with gasses and writing out an expression for a constant or Q, when do you use a P in the front and when do you just use brakets?

Blake_Katsev_2E

sorry i mean when you write it out as a formula

Blake_Katsev_2E

Why in triammineaquaplatinum(IV) chloride is the aqua written as H20 rather than OH2? it is listed after ammine acting like the O should come first because O is after N in the alphabet but H is before...

Blake_Katsev_2E

Why would in pentaamiminechloronickel(III) chloride the ammine be placed before the chloride? I thought that they are listed in alphabetical order and C comes before N.

Blake_Katsev_2E

When do you use bis and tris rather than bi and tri?

Blake_Katsev_2E

Why would the 2sigmaP come before the 2piP? if hydrogen has less protons than Oxygen, should the Pi orbital come first? Also how would you draw the bonding and antibonding orbitals for such case?

Blake_Katsev_2E

When the question says follow the octet rule does that mean that the central atom has to have 8 e- or can it have an expanded octet?

Blake_Katsev_2E

Which P orbitals form with s to create SP first? Also which P's create Pi bonds? is it Pz's?

Blake_Katsev_2E

Do lone pairs affect hybridization? like for example, a central with three bonds and a lone pair would be sp2 or sp3?

Blake_Katsev_2E

Anybody know what the material goes up to for the midterm?

Blake_Katsev_2E

Hello, why would this molecule in problem 25.d be polar?

Blake_Katsev_2E

Why would ClO2 + be trigonal pyramidal and not bent?

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