CHEMISTRY COMMUNITY

Monica Habashy 3A

It depends on the atomic masses of the halogen. The heavier one gets priority.

Monica Habashy 3A

A is the pre exponential factor. Usually it's the same in throughout a type of reaction. You could be asked to find it if you are given all the other values.

Monica Habashy 3A

You use them when you notice the trends in the way they are ordered in terms of priority.

Monica Habashy 3A

I'm a little confused as to what torsional strain is. Can anyone explain it?

Monica Habashy 3A

for the Gibbs free energy diagrams, do we look at delta G of activation for the second step from the intermediates to the transition state or in terms of the reactants to the transition state.

Monica Habashy 3A

iso is used for the general shape of (CH3)2CH, tert is when you have a T shape made up of carbon atoms.

Monica Habashy 3A

How many types of energy profiles are there? I know there's an energy profile in terms of Gibbs free energy and one in terms of potential energy...are there any others we need to be aware of? What are the differences between the Gibbs free energy and the potential energy ones?

Monica Habashy 3A

The overall characteristic depends on the central atom and since C is in this case an electrophile because it is slightly positive, the molecule is therefore electrophilic.

Monica Habashy 3A

Halogens are electron rich which is why they are nucleophiles.

Monica Habashy 3A

Did you use the ln(k2/k1)=-Ea/R(1/T2-1/T1) formula? Cause when you do that with the known values you get 5611j/mol as your activation energy. Then you use that value with the same equation, replacing one of your K values and its corresponding T values for the 700K and solving for K which gives you t...

Monica Habashy 3A

Can an "iso" group be at the end of a carbon chain or does it always have to be in the middle?

Monica Habashy 3A

Will quiz number 3 cover the kinetics stuff that we reviewed last week or will it be strictly organic chemistry?

Monica Habashy 3A

Second order reactions are 1/A vs time therefore the slope increases as concentration decreases which is why the slop for that is positive.

Monica Habashy 3A

The units of the rate constant vary depending on the reaction order.

Monica Habashy 3A

Yes, Dr. Lavelle posted the answers under the "Quiz 2 Winter 2017" post.

Monica Habashy 3A

When do we use the steady step approach vs the pre equilibrium approach?

Monica Habashy 3A

Why did they use water for the other half reaction?

Monica Habashy 3A

I don't think you get marked off for writing J or KJ unless the question specifies that you give it to one form or the other. Also it doesn't affect the sig figs, those primarily depend on the values given in the question.

Monica Habashy 3A

I don't think so.

Monica Habashy 3A

The heavier the molecule the greater the entropy. The less symmetry a molecule has the higher the entropy. So if you were to compare CH4 and CH2Cl2...CH2Cl2 would have a higher entropy because there is more disorder associated with the lack of symmetry.

Monica Habashy 3A

You look at the cell potentials. Whichever one is larger is the cathode and is therefore being reduced. The smaller, more negative value is the cell potential for the anode and is therefore oxidized.

Monica Habashy 3A

I don't think we learned solubility product...

Monica Habashy 3A

enthalpy kj/mol, entropy j/K*mol, free energy kj, heat kj, and work kj

Monica Habashy 3A

Reversible means that the reaction can easily go back to its initial form completely. It's like 100% of the reverse reaction went back to create its initial reactants which is why there is no change in internal energy.

Monica Habashy 3A

Will 1.0g of CH4 (g) have the same entropy has 2.0g of CH4 (g)? Or will the 2.0g of CH4 have greater entropy because entropy is an extensive property and therefore the increase in mass will result in greater disorder?

Monica Habashy 3A

because the reaction is reversible and isothermal at variable pressure you use the 1=-nRTln(V2/V1) formula

Monica Habashy 3A

You use the one with mass when you are given or are trying to find the Specific Heat Capacity. The one with just CdeltaT is used when you are just trying to find or are given the Heat Capacity. And the Cp is the heat capacity at constant pressure.

Monica Habashy 3A

Basically when you have constant volume of 1 atom of an ideal gas the molar heat capacity is 3/2R (R is rydberg's constant) Whereas if you have constant pressure of 1 atom of a gas the molar heat capacity is 5/2R. Now if you have linear molecules or non linear molecules these values differ. There's ...

Monica Habashy 3A

You use KJ per mole when you're finding the standard enthalpy of formation because it is the formation of 1 mol of a compound from its constituent elements. However, if you're just finding the enthalpy of a reaction you just use KJ. Also, my TA said that bond enthalpies can be written in KJ or KJ pe...

Monica Habashy 3A

I think you can pick them during week 3 of this quarter from 4006 Young Hall

Monica Habashy 3A

I think we start organic chemistry towards the end of the quarter so probably by then.

Monica Habashy 3A

Which would have the largest ionic radius? Cl- Br- I-

Monica Habashy 3A

On page 457 question 11.35 there's a formula used to convert K to Kc, are we expected to know that for the final? Did we go over this in class?

Monica Habashy 3A

Also for Kc you use these brackets: [ ] but for Kp you use normal brackets ( )

Monica Habashy 3A

Use P when dealing with pressures and brackets when dealing with concentrations.

Monica Habashy 3A

ethylenediammine it's a bidentate because it has 2 nitrogens. Each nitrogen is bound to only 2 hydrogens which means they have a lone pair of electrons that can bond to the transition metal.

Monica Habashy 3A

If both are positive you can figure out which one is correct by subtracting it from the initial concentration. If it gives you a negative initial concentration then you can disregard it cause the value is too large.

Monica Habashy 3A

Most of the time you can tell from the charge. Like F- Cl- OH- etc are all monodentates. SO42- is bidentate etc. Ethylenediammine is a bidentate cause there are 2 nitrogens each with one lone pair. So looking at the number of nitrogens can be a good indication of the number of bonds it can form.

Monica Habashy 3A

You would calculate the bond orders for each one and so the one would the highest bond order would have the highest ionization energy because the bond is stronger. Then you would compare if the electrons are higher or lower in energy. Electrons in the higher energy orbitals mean that they are easier...

Monica Habashy 3A

If there's an H2O outside the complex, do we refer to it as hydrate or aqua?

For example: K3[Fe(CN6)]3H2O

Monica Habashy 3A

The coordination number is the number of bonds formed. So from this you can deduce that the coordination number will be 6 because each NH3 will bind once and then there is a chlorine; this gives a total of 6. The oxidation number is solved by looking at the charges of each molecule. So the Cl2 charg...

Monica Habashy 3A

Ligands are electron rich species that bind to transition metal cations by forming coordinate covalent bonds

Monica Habashy 3A

I don't think so.

Monica Habashy 3A

We use the molecular orbital theory to give information about:
1. whether or not resonance structures exist (ex. if the bond order has a half in it (0.5, 2.5 etc) then the molecule has a resonance structure)
2. unpaired and paired electrons
3. bond energies

Monica Habashy 3A

Is nitrosyl (NO) bidentate?

Monica Habashy 3A

When writing out the chemical formula the order doesn't matter. However, when writing out the name then it's alphabetical.

Monica Habashy 3A

From the PLF sessions with the UAs they said that these questions won't be asked on the quiz since we haven't gone over them yet. Dr. Lavelle said only the first 4 pages of the equilibrium stuff in the course reader will be on the quiz.

Monica Habashy 3A

I think it's vanadate

Monica Habashy 3A

If it has lone pairs of electrons or a negative charge then it's most likely a polydentate and can bind to a metal in those regions.

Monica Habashy 3A

If they give you pressure then it's Kp if they give you concentration then it's Kc

Monica Habashy 3A

Using ferrate is the correct way but my TA said that we wouldn't need to use the latin names on quizzes/exams.

Monica Habashy 3A

I don't know if there will be class or not...but all the lectures are bruin cast.

Monica Habashy 3A

They have more energy because they are not bonded and therefore are more reactive. The bonded ones are more stable and as a result have lower energy.

Monica Habashy 3A

Okay, thank you.

Monica Habashy 3A

If we're asked a question about VSEPR theory but it says to draw a lewis structure, does it matter if we just draw any lewis structure of the compound? Or do we have to draw the most stable resonance structure?

Monica Habashy 3A

And I don't think you need to know f block orbitals.

Monica Habashy 3A

I think the only two we need to focus on are copper and chromium.

Monica Habashy 3A

Do practice questions from the course reader and the questions in the workbook as well.

Monica Habashy 3A

When writing out hybridization does it matter if we put d before s and p or after s and p? In the course reader it's written as dsp^3 but in the textbook solutions it's written as sp^3d.

Monica Habashy 3A

If you look at electron affinity values, all noble gasses have an electron affinity of 0.

Monica Habashy 3A

Hey, I just had discussion today and we got our actual quizzes and workbooks back. It says the points on it.

Monica Habashy 3A

Yeah! Why would that not be the case?

Monica Habashy 3A

We use it to specify which state each compound is in when running the experiment, but I don't think it impacts the molecular coefficients at all.

Monica Habashy 3A

It means that it doesn't have wavelike properties because it is too small to detect. Usually anything with a 10^-15 is the smallest wavelength that portrays these wavelike properties. Anything smaller cannot be detected consequently, you would say that it does not have wavelike properties.

Monica Habashy 3A

I'm In C7 and I want to join! Did you guys make the study group yet?

Monica Habashy 3A

It's not too late to join right?

Monica Habashy 3A

Oh Alright! Thank you so much!

Monica Habashy 3A

Do we have to do anything before tomorrow's lecture?

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