CHEMISTRY COMMUNITY

Dahriel Aron 3A

Do we need to know any functional groups besides ketone, ether, carboxylic acid, alcohol, and aldehyde for the final?

Dahriel Aron 3A

if told to draw a cyclohexane that is either trans or cis with 3 substituents, how do you know which do to make up and which to make down for trans? would you make them all either up or down for cis?

Dahriel Aron 3A

Is it true that ethers and alcohols are functional groups that dont get priority in naming?

Dahriel Aron 3A

Hello, I noticed in the practice finals there are a few questions that ask you to derive rate laws using integrals such as 4A on the 2014 final which asks to derive the integrated rate law for a second order reaction with A as the only reactant. However, I thought that I remembered Professor Lavelle...

Dahriel Aron 3A

Is there always only 1 intermediate in electrophilic addition when there are 2 transition states? I thought that there were 2 in the example of Br2 attaching to a large molecule with a double bond since one would be the Br attached to the large molecule with a carbo cation and one would be the secon...

Dahriel Aron 3A

what exactly is the relationship between arrhenius and temp

Dahriel Aron 3A

will we have to know anything about kinetic control for quiz 3?

Dahriel Aron 3A

If there are 2 substituents that are the same length apart, which would get prioritized for the lower number in naming: chloro or ethyl? or chloro or methyl?

Dahriel Aron 3A

but why wouldnt it attack it from the lone pairs and not the single bond on the RCL

Dahriel Aron 3A

could you have drawn this in a straight line instead of curved the way it is in the answers?

Dahriel Aron 3A

This question asks to name ch3chch3chch2ch3c(ch3)3 and I got 3 ethyl 2,2,4 trimethylpentane however the answer is 2,2,4 trimethyl ethylpentane and I dont understand why the triMethyl is getting alphabatized and placed before the Ethyl

Dahriel Aron 3A

For this question it asks to draw 7-flouro-3-methyl-4-vinyl-nonane, However in the answer the longest chain only has 8 carbons even though its nonane (9 carbons) and there is a double bond even though it is -ane not -ene so I'm confused why this is. Also, I thought vinyl meant c2h3R and I do not see...

Dahriel Aron 3A

This question asks if the activation energy in an organic rxn is 125 kj/mol, will the rxn occur at room temperature and I was wondering why the answer is no

Dahriel Aron 3A

In 4.25 it shows an arrow flowing from a double bond to a Br2 molecule. In the br2 molecule the br that the arrow first points to is marked as electropositive in the answers and the second br is marked as electronegative and I was wondering how to decipher which would be the negative and which would...

Dahriel Aron 3A

Do we need to memorize the nucleophiles and electrophiles listed in the o chem book

Dahriel Aron 3A

is it only the tert- and sec- group that you do not look at the prefix when placing in alphabetical order?

Dahriel Aron 3A

I was wondering if anything from the end of ch 15 will be on the quiz

Dahriel Aron 3A

in using the arrhenius how would you know what to plug in for A?

Dahriel Aron 3A

How can you find the activation energy from just knowing the order of the reaction and k?

Dahriel Aron 3A

This question asks how long it takes the reactant concentration to drop from .0840 to .0220 with k= 8.39. I used ln final/initial = -kt and got .159 seconds but the answer is 4 seconds, and I was wondering what the right way to do this was?

Dahriel Aron 3A

I hope everyone is feeling solid (with low entropy) for the midterm tomorrow!

Dahriel Aron 3A

Hello, both 11.19 and 11.83 ask to calculate the equilibrium constant k for chemical equations, however 19 just simply asks to calculat k at 25 degrees celsius and 83 asks to calculate k at 25 and at 150 degrees celsius. However, in 83 to solve this problem it uses delta G= delta h - T delta S, and ...

Dahriel Aron 3A

Hello,
Sorry I'm not sure where to properly ask this question, but I was wondering what all the sections the midterm will be covering are?

Dahriel Aron 3A

for this problem, I was also wondering why they divide the enthalpy of fusion for ethanol by the freezing point and not the melting point to find its melting entropy

Dahriel Aron 3A

for this question it says that 50g h20 at 20 degrees celsius is mixed with 65g of h20 at 50 degrees celsius and wants delta s and delta s total. In the solutions manual it uses q=-q and uses 75.3 for the specific heat. I was wondering where the number 75.3 comes from

Dahriel Aron 3A

does q= delta h at constant pressure? and does delta u = delta h at constant volume?

Dahriel Aron 3A

does delta g equal zero when the temperature is 0 or when its at boiling point?

Dahriel Aron 3A

In the homework for chapter 8 I noted that sometimes in calculating q the book sometimes multiplied the specific heat and the change in temperature by the grams and and other times multiplied the specific heat and change in temp by mols and I was wondering why that is

Dahriel Aron 3A

In question 9.71 it asks Which substance would you expect to have the highest molar entropy in the liquid phase, benzene, methanol (CH3OH), or 1-propanol (CH3CH2CH2OH)? In the solutions manual it says that it is benzene because it has more of a rigid shape. I was wondering what it meant by rigid sha...

Dahriel Aron 3A

In question 9.89 it asks, Some entries for S in Appendix 2A are negative. What is common about these entries, and why would the entropy be negative? The solutions manuals answer did not really make sense to me and I was wondering if someone can explain the reasoning behind this. Is it just because t...

Dahriel Aron 3A

In question 9.103 it asks A scientist proposed the following two reactions to produce ethanol, a liquid fuel: C2H4 (g) + H20 (g) -> CH3CH2OH (l) C2H6 (g) + H20 (g) -> CH3CH2OH (l) + H2 (g) Assume standard-state conditions and determine if either reaction is thermodynamically spontaneous. I initially...

Dahriel Aron 3A

What would cause one molecular substance to have a higher molar heat capacity than another molecular substance?

Dahriel Aron 3A

In question 8.117 it states One step in the production of hydrogen as a fuel is the reaction of methane with water vapor: CH4 + H2O --> CO2 + 3 H2 enthalpy= -318 kJ What is the change in internal energy for the production of 1.00 mol H2? In the solutions manual they multiply by 2/3 mol to find the...

Dahriel Aron 3A

Regarding question 8.15 which asks, in an adiabatic process, indicate whether which statements are true, false, or uncertain in a closed system a) internal energy equals 0 b) heat equals 0 c) heat is less than 0 d) internal energy equals heat e) internal energy equals work I was wondering if someone...

Dahriel Aron 3A

When you are given all of the initial concentrations for an equation, is it safe to always just calculate the Q and compare it to the K to determine which way the reaction is going? I remember Professor Lavelle saying in office hours that this strategy does not always work and that sometimes we shou...

Dahriel Aron 3A

A tutor taught me how to calculate the steric number to easily determine the geometry of a structure based on its chemical formula, but I forgot how to calculate this number. Does anyone know how to get the steric number? I only remember that oxygens are not counted or included in this number.

Dahriel Aron 3A

How do you write the formula for a conjugate base? For example, CH3COOH?

Dahriel Aron 3A

while doing the homework I noticed that sometimes my answers sig figs didnt match up with the books answers. For this section, is it a good idea to keep the amount of sig figs matched to the amount of sig figs that will be in the final answer? Or should we keep a lot of sig figs and only cut down at...

Dahriel Aron 3A

So can you only set x to a very small number close to 0 when its something - x or can you also do this when it is something + x

Dahriel Aron 3A

For pentaaquachloroiron(III) would the chemical formula be:
[Fe(H2O)5 (Cl) ] 2+ since theres no counter atom
or
[Fe (H2O)5 Cl)3] to make a neutral charge ?

Dahriel Aron 3A

Do you usually want pressure to be in the units of atm?

Dahriel Aron 3A

On page 49 of the green workbook number 9 it says:
name the complex ion
[Cu(NH3)CL5] 3-
and the answer is either amminepentachlorocuprate (II) ion or amminepentachlorocopper(II) ion
why are there 2 possible answers? Is it because there is no counter ion?

Dahriel Aron 3A

Should we just make it a general rule to attach the word "ion" to the end of every name?

Dahriel Aron 3A

When there are 2 carbonatos, do we use bis- or di- ?

Dahriel Aron 3A

when writing our the formula for oxalato, can we abbreviate it ox or do we need to write c2o4?

Dahriel Aron 3A

For this first one, I thought it would be chromium III not chromate III since it is a cation. Do you also add -ate to cations?

Dahriel Aron 3A

oxygens want 2 lone pairs and 2 bonds, so when the oxygens with 3 lone pairs make a bond, it is the most favorable. This happens 4 times in edta. The two nitrogen are also left with one single lone pair which can become a bond as well. Altogether, this creates 6 sites for bonds making edta hexadenta...

Dahriel Aron 3A

"For the following rxn, if initially .1 mol h2o is placed in a 4 l vessel, what are the equilibrium partial pressures of each product and reactant? kp= 3.72 at 1000 k h2o + c = h2 + co " For this problem I got x=.034 and plugged that number in to calculate the equilibrium of all of the rea...

Dahriel Aron 3A

IS the bond angle for square pyramidal 90 degrees or less than 90 degrees?

Dahriel Aron 3A

"An electron is moving at v=3.78x10^5 m/s. A neutron is moving at the same velocity. Which particle is the position known with the greatest precision and why"
For this question would it be the electron since it has a smaller mass? Or would it be a neutron because that has a greater mass?

Dahriel Aron 3A

Is a molecule more stable with a larger bond order? I thought that bond order correlated with the type of bond (single, double, triple) and that the more bonds there were the shorter the bond was, and the less stable it was. But do short bonds mean that the bond is more stable? In the practice quiz ...

Dahriel Aron 3A

it would just be sp^3. You only want to look at how many regions of electron density there are with hybridization, not at where the elements are in the periodic table. Since there are 4 regions of electron density, the hybridization is sp^3

Dahriel Aron 3A

I'm getting my answers from the solutions manual, and they had that answer which is why I am confused. Are you suggesting that the solutions manual is wrong?

Dahriel Aron 3A

For 3.19, it asks the electron configuration for sb (3+). I put [kr] 4d10 5p2 because I thought that you take off the s orbital first, but the answer is [kr] 4d10 5s. However, in a similar problem 3.5, they say that the electron configuration for bi(3+) is [xe] 5d10 6p2 since they took off the s orb...

Dahriel Aron 3A

I was wondering if someone could explain to me how to tell the difference between when a molecule will be AX3, AX4,AX3E,AX2E,AX2,and AX2E2. For example, how do you know that CH2 would be AX2E, but CH2(2+) would just be AX2?

Dahriel Aron 3A

When drawing a lewis structure with a double/triple bond, how does one know to give that structure a double bond instead of just a single bond with more "." around it? For example, with H2CO, how do you know to draw it with a double bond between the C and O and 4 "." around the O...

Dahriel Aron 3A

How would you know which N to give a +1, 0, or -1 charge to?

Dahriel Aron 3A

I do not fully understand the quantum value of ml. Does it determine if an element is magnetic or does it determine the orbital? Also, say that n=4, l=2, and ml=-2. How would I use that information to determine how many electrons can have those quantum numbers in an atom?

Dahriel Aron 3A

Hey guys, While I did the homework over the summer I noticed that a lot of times I would come up with an answer of say 40.07, and the answer in the solutions manual would say something like 40.13. This probably has to do with discrepancies in the amount of sig figs used throughout all of the calcula...

Dahriel Aron 3A

After watching the videos I am very confused about the difference between atomic emission spectrum and atomic absorption spectrum. My interpretation from the videos was that these 2 ideas were the same concept, although now it has become clear that they have differences between them. I was wondering...

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