CHEMISTRY COMMUNITY

Akash_Kapoor_1L

http://www.chemistryjokes.com/images/th ... fusion.jpg

Me during that entire final

Akash_Kapoor_1L

In that case would there have been a couple different ways to set up that equation, cause I feel like what I did was right, but it was a different set up from what one of my friends did.

Akash_Kapoor_1L

What did people say for the True and False questions. Specifically the one of macrostates of molecules

Akash_Kapoor_1L

How do you find these old finals?

Akash_Kapoor_1L

I actually learned to calculate this and turned out it wasn’t on the final. But it’s good to know the concepts.

Akash_Kapoor_1L

Thank you Dr. Lavelle!!

Akash_Kapoor_1L

Not sure how I feel about that test

Akash_Kapoor_1L

How do we know when to use a pseudo-first-order method instead of calculating the second order rate law normally?

Akash_Kapoor_1L

I agree with Nora^^ It's usually used to define exponential inequalities

Akash_Kapoor_1L

I'm pretty certain that the variable A is also defined as the frequency factor.

Akash_Kapoor_1L

Why don't we factor in the delta H of fusion into our calculation of the final temperature of water in these problems? Wouldn't some heat energy be lost in melting the ice cube or am I just overthinking the problem?

Akash_Kapoor_1L

Would we need to know calculations related specifically to enzymes for the final or will we only need to know conceptual material?

Akash_Kapoor_1L

What is the split of questions on the final? Relatively how much of the final will be on older material (like Enthalpy and Entropy) and how much of the final will be on the newer material??

Akash_Kapoor_1L

You would start with the equation: ln(k 2 /k1 1 ) = E a /R * ((1/T 1 ) - (1/T 2 )) Where T 1 = 25 Degrees Celsius = 298 K Where T 2 = 37 Degrees Celsius = 310 K Where k 1 = 1.5 * 10^10 and you need to find k 2 So after computing this equation and making sure that you convert the value for R from J i...

Akash_Kapoor_1L

What kind of questions would we get asked on the final about adiabatic processes, would they all just be conceptual? Will the topic be on the final?

Akash_Kapoor_1L

The Syllabus told us to omit section 15.9 from our readings and there weren't any hw problems assigned on radical chain reactions. So to what extent do we need to know about radical chain reactions on the final? Would we just need to know the concept? Or is there anything else involved?

Akash_Kapoor_1L

To determine reaction order you would add the coefficients of the concentrations in the Rate law. For example, if the rate law = k[A]^2 * [B]:
The Reaction is Second-Order in terms of A, First-Order in terms of B, and (2+1) Third-Order overall.

Akash_Kapoor_1L

If the value is not an integer then the units of k are proportional to the fraction. For example, if the reaction order is 3/2 then, the units of k would be L^1/2 * mol^(-1/2) * s^-1. The overall intention is to end up with the rate in (mol * L^-1 * s^-1), so you would modify the units of k to get t...

Akash_Kapoor_1L

The specific integrate rate laws that we have found are integrated using the rate of loss of reactants. The short answer to your question is yes. However, there could be problems (similar to #23 (part c)) where you are given the concentration of the product and the molar ratio of products to reactan...

Akash_Kapoor_1L

how do you get rid of the negative?? You get rid of the negative by flipping the natural log... Use the laws of logs and remember that ln[At]/[Ai] = ln[At] - ln[Ai], so if you bring the negative to the other side, you turn that into ln[Ai] - ln[At] = ln[Ai]/[At] This is why you get: t = 1/k * ln[Ai...

Akash_Kapoor_1L

Apart from what Remi said, the main reason you need to use the integrate rate laws instead of the logarithmic shortcut is because the rate of change in the concentrations of the reactants follows a curve which isn't depicted in the half-life formula. We find the half-life as ln2/k, but the only reas...

Akash_Kapoor_1L

What is the best way to convert between different units of k? Would we ever have to convert k from L/ mol*s, into 1/ kPa*s?

Akash_Kapoor_1L

Do we have to know how to calculate the limiting step for test 3? Which hw problems focus on the limiting step?

Akash_Kapoor_1L

Could someone give some examples of a 3rd or 4th order reaction that we might see on a test? I've only seen 1st and 2nd order reactions in the textbook really.

Akash_Kapoor_1L

Could someone explain what methods you would use to find k' in a pseudo reaction?

Akash_Kapoor_1L

I didn't find any in the textbook, but this website has some pretty good practice questions at the end.

https://chem.libretexts.org/Core/Physic ... _reactions

Akash_Kapoor_1L

To what extent do we need to know/ be able to draw graphs for the different reaction orders?

Akash_Kapoor_1L

This is a great question! I was lowkey confused about this too. The easiest way to know is based on the units that they give you and the units you want to end up with. You know that you want the entropy, which is in J/K... But the specific heat capacity value that they give you is in J/C*g. The only...

Akash_Kapoor_1L

In the solutions manual, they say that "the reaction we want is" N2 + 5/2 O2 ----> N2O5
I'm not sure where they got the reaction from. Also is there a similar example to this in the textbook, because I'm not sure what method to use to solve this.

Akash_Kapoor_1L

Is there a difference between enthalpy and molar enthalpy?? How would you covert one to the other?

Akash_Kapoor_1L

So if you are just given the grams of a strong acid and the volume of the solution, how would you calculate the pH of the solution??

Akash_Kapoor_1L

I feel like they would just keep it for you until you are able to pick it up...

Akash_Kapoor_1L

This thread is actual gold...

Akash_Kapoor_1L

Will we be given pKa values? Or will we need to memorize/calculate them??

Akash_Kapoor_1L

When H+ is transferred in a reaction, is it concerted a bronsted or Lewis acid/base reaction? Is H+ always considered a Lewis acid?

Akash_Kapoor_1L

I was confused about the same problem... Why do they give you the amount of ammonium carbamate and the temperature? Is there an alternate way of solving the problem that uses those two quantities??

Akash_Kapoor_1L

When drawing dipole moments are we supposed to use the original convention or the "modern convention" that is used in the textbook? The original convention points the arrow towards the more electronegative (negative charged) element, whereas the modern convention points the arrow towards t...

Akash_Kapoor_1L

Here's a great chart which might help you. http://web.gccaz.edu/~chriy68124/VSEPR%20handout.pdf

Akash_Kapoor_1L

Yeah it does! Here's a helpful chart http://web.gccaz.edu/~chriy68124/VSEPR%20handout.pdf

Also, remember that you can use the AXE format to decipher the VSEPR geometric shape...

Akash_Kapoor_1L

What method do we use to name the isomers as 1-, 1-3, and 1-4?

Akash_Kapoor_1L

In question number 23, Chapter 3, the textbook asks us to find the maximum positive and negative oxidation numbers for Chlorine. I think I'm just confused on the general method for deriving the maximum oxidation numbers. How do we figure out what the maximum oxidation numbers would be??

Akash_Kapoor_1L

You would use up the d orbital of the highest energy level. For example in Sulfur, since you already have electrons in the 3s and 3p orbitals, you can also fill the 3d orbital with electrons... Recall how in the last chapter we looked at quantum numbers and if n=3, l = 0,1,2; thus any atom with n=3 ...

Akash_Kapoor_1L

When do f orbitals come into play when considering chemical bonds and lewis structures? In the same way that atoms can fill up their d orbitals, can even larger atoms fill up their f orbitals too??

Akash_Kapoor_1L

Also make sure that you memorize the equation or know the concept behind calculating formal charge, because Dr. Lavelle said that he won't provide the equation on the reference sheet!!

Akash_Kapoor_1L

Also, yes, the most dominant and stable resonance structure will be the one with the lowest energy, which means that it will have a formal charge closest to 0...

Akash_Kapoor_1L

Remember to use the equation, Fc = V - (L + s/2), where V = the number of valence electrons, L = the number of lone electrons, s= the number of shared electrons to calculate the formal charge of each atom in the molecule!!

Akash_Kapoor_1L

Will the Heisenberg Indeterminacy Equation be given to us for Test 3 or should we know it for the test?

Akash_Kapoor_1L

I had a similar question, which elements have the greatest tendencies to form Pi bonds and why do elements form Pi bonds instead of other alternatives?

Akash_Kapoor_1L

Can we do this problem without using Rydberg's Formula? I'm trying to solve it with E= -hR/n^2, but I keep getting a decimal number... I'm not sure if I'm just doing the calculation wrong or if there is a problem with my method

Akash_Kapoor_1L

The only thing that you forgot was the stoichiometry, you need to convert the given data from kg/mol to J/atom ... Otherwise you are correct because the Work Function is defined as the Energy Required to Remove an Electron.

Akash_Kapoor_1L

If you are using slightly different symbols, you should make sure to define what each symbol is representing on the top of the blank space... As long as you do that, I don't see any reason for you to lose points. But also reach out to your TA, just in case

Akash_Kapoor_1L

Should we memorize the specific wavelengths that correspond to certain colors and types of waves in the electromagnetic spectrum or will these be given to us on tests? (ex. 700 nm=red or 100 nm = ultraviolet)

Search found 52 matches