CHEMISTRY COMMUNITY

Shibhon_Shepard

memorize this (it hasnt been on the sheet)
[A]t=[A]o -kt

Shibhon_Shepard

Does anyone have an example of this either from a book or a review session that goes step by step? thank u

Shibhon_Shepard

Yes the acid/base comes from the salt!

Shibhon_Shepard

the more H3O+ ions there are the stronger the acid, so lower H3O+ ions means higher pH. (It's completely based on the H3O+ ions)

Shibhon_Shepard

No units for any of the equilibrium constants.

Shibhon_Shepard

when calculating for R just use the 8.314 value

Shibhon_Shepard

the C- is a 50% but it depends on the class average that it is scaled to that.

Shibhon_Shepard

The unique rate has more to do with their relationship with each other like a product with a reactant.
The instantaneous rate is the tangent line when their is a change.

Shibhon_Shepard

i always convert back to mol because that's like the official units

Shibhon_Shepard

they are different depending on the order.

so the 1st only has s^-1
2nd: mol*L^-1*s^-1
3rd: mol^2 *L^-2 *s^-2

Shibhon_Shepard

initial rate is the one thats usually given but if the rate in general is given to you then you use the equation to do (k*any concentration that you are at) , versus initial has to do with the concentration in the beginning.

Shibhon_Shepard

the larger the Ka, the stronger the acid.

Shibhon_Shepard

it just means that in this example water can be an acid and a base. With this said, some of them would give away their H+ and become OH- and the one receiving the proton would become H3O+ .

Shibhon_Shepard

But are they going to give us a problem that is x^3?

Shibhon_Shepard

if Q>K , the reaction moves to the reactants.
if Q<K, the reaction moves to the products

Shibhon_Shepard

how do you calculate the partial pressure? and how does that relate to concentration?

Shibhon_Shepard

if the problem states that it is isothermal, q=0 and q=-w, since delta U = q+w, 0+0=0

Shibhon_Shepard

Yes, 298 Degrees Kelvin is the standard for ideal gas.

Shibhon_Shepard

if its just the C(delta) T, you are already included the amount of moles, instead of adding it in the beginning.(aka when you only have one mole)

Shibhon_Shepard

But keep in mind that delta H has a lot to do with this. and when measuring delta H you would measure from the beginning to the end state. (even if it does a big loop up, its just beginning and end result)

Shibhon_Shepard

What are the main things you would look for to determine its in the most stable form?

Shibhon_Shepard

You usually use R=8.314 , but the other values for R are given on the equation sheet.

Shibhon_Shepard

There are some times that they give you the C or heat capacity and you would just multiply this C by the number of moles.

Shibhon_Shepard

for the most part it should state that it is isothermal or that the temperature is constant.

Shibhon_Shepard

Think about it in terms of yourself.
if you're doing a workout, you lose energy.
But if someone else is doing it, you're positive energy.

Shibhon_Shepard

He will also give a ton of review sessions for the final in week 10 .

Shibhon_Shepard

The best way to determine this is just to look if you can cancel out all the units.

Shibhon_Shepard

This "assume ideal behavior" just means you can us PV=nRT equation

Shibhon_Shepard

just C is the heat capacity. C subunit P, is the heat capacity at the constant pressure. C subunit V is the heat capacity at constant volume.

Shibhon_Shepard

the tests themselves are not curve. but as long as you get 250 points out of 500 points in the whole quarter you get a C-

Shibhon_Shepard

you determine the order based on the amount of electrons and the size of the atom. for Anions you are looking for the one that is more negativity. and for the cations you are looking for the most positive.

Shibhon_Shepard

Only the lone pairs on the central atom affect the shape right? not the lone pairs on the other ones?

Shibhon_Shepard

marg44 wrote:For these sigma and pi bonds, is one bond stronger than the other? Or are they of equal strength?

Sigma bonds are stronger and pi bonds are weaker.

Shibhon_Shepard

Can someone explain the correlation between the bond strength and resonance structures?

Shibhon_Shepard

if it is on the final, is it used as a concept question or something more than that?

Shibhon_Shepard

Can someone re explain this concept briefly ? i know we are not doing calculations (just conceptual) right?

Shibhon_Shepard

How do you determine what inter molecular forces could be present in a molecule?

Shibhon_Shepard

what are some questions that could be asked on the final using pH?

Shibhon_Shepard

Can someone name all the strong acids? I know that it's a short list.

Shibhon_Shepard

That makes so much more sense! thank you!

Shibhon_Shepard

Can someone give a concrete example that would help better visualize this? thanks

Shibhon_Shepard

If you do draw them out, I would recommend explicitly writing the degrees somewhere just to be safe. This will also show your TA that you know what bond angle is actually there without having to actually draw out a 109.5 degrees vs a 120 degree angle.

Shibhon_Shepard

This isn't something we particularly have to know, but its just saying that the shape plays a role in how certain things function. Like a protein would work better folded in a certain way vs if it was just a chain of amino acids. The shape can either improve its ability or diminish it.

Shibhon_Shepard

It has to do with the fact that they are both bonds. (vs it being lone pairs) because all ends are bonds and there are no lone pairs. the repelling is equally distributed.

Shibhon_Shepard

For these exceptions are we able to draw a Lewis structure for them? (if any)

Shibhon_Shepard

Can someone please give a formal definition to what resonance structures are? and why we use them?

Shibhon_Shepard

Is there a difference between the stable charge and the formal charge? if they are explain please and thank you.

Shibhon_Shepard

Does the distance between the bonds effect the boiling point? Would this cause the bond to be stronger or weaker? This distance between the bonds would have an effect on the boiling point or how easily the bonds are broken. This is how I think about it to determine whether it is a stronger bond or ...

Shibhon_Shepard

I think most of what he was referring to with boiling point and shape, was how if there is more surface area touching than the rod for example would be a harder bond to break, versus when you look at to circles only has a little piece touching there for it is an easier bond to break.

Shibhon_Shepard

Okay, if the negative is releasing or absorbing energy what does the positive indicate?

Shibhon_Shepard

WHAT DOES THIS EVEN MEAN????? I don't even remember this being talked about.

Shibhon_Shepard

To find how many degenerate orbitals there are using Ml.
let's say L is 1.
so Ml is =-1,0,1
by that we count how many there are in Ml (3). so we have three degenerate orbitals for this atom.

Shibhon_Shepard

Lavelle explained a bit more on the lengths and strengths of the bonds in class on Wednesday. I would ask him if you still have any doubts.

Shibhon_Shepard

Hi, can someone write like exactly what order we are suppose to write the configuration? because i keep getting mixed answers on whether s or d goes first. thanks

Shibhon_Shepard

wait, how does a negative indicate a higher state? is it because electrons are negative and as you have more it becomes more negative?

Shibhon_Shepard

So if this is the case, did this have to do with the question on Test 2 about the probability of finding an electron in the center of an atom?

Shibhon_Shepard

The standard one for this equation is Liters, but if asked otherwise, you should probably use liters for your volume.

Shibhon_Shepard

How I understood this was once you fin the amount in grams, the one with the bigger amount of moles that is need for the reaction is the limiting reactant. this is because you need more of this reactant to complete the equation. M9 in the textbook wasn't too much if you wanted a better idea with sma...

Shibhon_Shepard

I also got confused here.

But as in the beginning it says you are looking the amount of moles and even though it says molecules you're looking for the amount of moles in that molecule they presented.

Shibhon_Shepard

Lavelle said the only way this could happen was in a nuclear reaction, but that we didn't have to worry about this until later.

so it can only be the same as or less than.

Shibhon_Shepard

would you use the inverse if you're going in the opposite direction?

can someone clarify what would it be for :
- atoms to moles
- moles to atoms

thank you

Shibhon_Shepard

you would multiply the actually quantity of gallium you have (9), by the molar mass given 70g/mol. this total will be equal to the molar mass of astatine 210g/mol times the amount of astatine you have. The amount of astatine is unknown so put a variable and then solve for it.

9 x 70 = 210 x A

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