CHEMISTRY COMMUNITY

Nicole Jacobs 1C

it is given that 1E-16 is the molarity of cu2+ in the question and since cu2+ is the reactant, you put its concentration in the denominator

Nicole Jacobs 1C

remember only the second order has a positive k slope

Nicole Jacobs 1C

if you were going from gas to liquid, then it would be exothermic because phase changes of vaporization and condensation are the opposite

Nicole Jacobs 1C

you should be able to look at a complex molecule and identify which functional groups are in it

Nicole Jacobs 1C

do we have to know how to apply a psuedo first order reaction or just understand it conceptually?

Nicole Jacobs 1C

the catalyst is in the reactant side of the first step and in one of the other steps it is on the reactant side, so it is used

Nicole Jacobs 1C

the reaction vessel is 750 mL so use this to find the molarity of H2 and I2 to find moles per liter

Nicole Jacobs 1C

use the units for k requested in the question because sometimes it asks per second and sometime it asks per minute

Nicole Jacobs 1C

for ln(1/2) and ln(2/1), they give the same value, just one is negative and one is positive, if that helps

Nicole Jacobs 1C

What is the difference between the zero, first, and second reactions? i still dont really get it

Nicole Jacobs 1C

Are we only being tested on problems that have to do with material up to #39 for quiz 3?

Nicole Jacobs 1C

How do you tell if the reaction is controlled by thermodynamics? by kinetics?

Nicole Jacobs 1C

remember not to multiply E by a factor when you are balancing the equations. Unlike H and S, you do not multiply E by the coefficients you use to balance the equations, since E is intensive.

Nicole Jacobs 1C

what is the order in which we are supposed to write the cell diagram? Our TA told us to write reactants first then products but that doesnt seem to match the solution manual

Nicole Jacobs 1C

Will we be expected to write the whole cell reaction and use nerst equations for word equations? like without the elements and compounds explicitly written in their molecular formulas?

Nicole Jacobs 1C

Yes it is a state function because it does not matter the path that it takes to get to the final condition. Also remember delta S and delta H and delta G are state functions as well

Nicole Jacobs 1C

Our TA told us that we would be given a diatomic or monatomic obvious molecule, or if it is not obvious, it will be given explicitly in the question

Nicole Jacobs 1C

i think we mostly need to know just how K (and Q) relate to Gibbs free energy for the part of chapter 11 that we will be tested on

Nicole Jacobs 1C

Will the material covered on Test 2 be up until the 14th or the 16th of February?

Nicole Jacobs 1C

it also helps to redraw the molecule as many times as you can by rearranging the element placements, almost like you would with a resonance structure, to show how many different states the molecule can have.

Nicole Jacobs 1C

How did they get the equation in 89 and how did they get the partial pressures out of 100? Im confused reading the solution manual for this problem.

Nicole Jacobs 1C

On Outline 1 on Lavelle's website, it states this as the last learning goal bullet: "Understand the environmental impact of burning fossil fuels, and the use of alternative
fuels". Will we have to know this even though Lavelle did not cover this in lecture?

Nicole Jacobs 1C

Are the only state functions we've learned so far deltaH, detltaG, and deltaU? But the w and q are not state functions?

Nicole Jacobs 1C

My TA told us it is due 11:59 in Sundays

Nicole Jacobs 1C

If i understand correctly I think it is because when deltaG is 0, that is the system's boiling point, and when deltaG is negative, the reaction is favorable. So bromine would vaporize, or become a gas from a liquid, at any point equal to or above 333K because this is when Br2 has its boiling point

Nicole Jacobs 1C

you can also see this with the heating curves. for example, when ice is melted into liquid water, there is a plateau where there is heat being added but the temperature remains constant. this means molecules are transferring energy faster, but there is not a significant increase in the how fast the ...

Nicole Jacobs 1C

i believe you would say the amount you found in positive, followed by the word released. for example, -55 kJ could be answered as 55 kJ released. hope that helps!

Nicole Jacobs 1C

also, make sure to multiply the bonds by the number of moles for each reactant and each product!

Nicole Jacobs 1C

Will we have a formula sheet for this quiz? And will it be the same one as 14A or will it be different?

Nicole Jacobs 1C

R should also be given on the formula and constant sheet Lavelle gives us for the test

Nicole Jacobs 1C

our TA also said if the c of the calorimeter is given in the problem you need to add it to q of Cu. Thus, the equation could be q of H2O = q of Cu + q of calorimeter

Nicole Jacobs 1C

i also think w is negative when the reaction is expansive and the delta V is positive, and 0 when the reaction takes place in a vacuum with free expansion.

Nicole Jacobs 1C

where do the homework problems start since we are starting halfway through the chapter? Also what section in the book are we starting from within chapter 8?

Nicole Jacobs 1C

And vice versa, if you were to add bonds, the reaction would be exothermic because energy is released when bonds are formed. Thus it would be negative if you were talking about the opposite.

Nicole Jacobs 1C

What is the difference between standard enthalpies of formations of solutions and standard enthalpies of formations of gases?

Nicole Jacobs 1C

I understand that only temperature changes K and that adding more reactants or more products does not change the K, but how come when you do the reverse reaction (1/k) the K value changes?

Nicole Jacobs 1C

How can you tell it is a strong acid or strong base just by looking at the molecular formula?

Nicole Jacobs 1C

when you have a single bond, it is a sigma bond. A double bond consists of a sigma and pi bond, one for each bond line. A triple bond consists of a sigma and 2 pi bonds, one for each bond line as well.

Nicole Jacobs 1C

Also, the coordination sphere is referring to a central (metal) atom and its array of molecules or anions (ligands) around it. The coordination sphere consists of anything within the [ ] of the compound name.

Nicole Jacobs 1C

In lecture, Lavelle said that we should give the K constant based on what is given to us, so if pressures are given, use Kp and if concentrations are given, use Kc.

Nicole Jacobs 1C

What range of the homework problems on the syllabus should we do to only practice the 11.1 -11.8 material that will be on the next exam?

Nicole Jacobs 1C

Do we need to know all the common ligands listed in figure 17.4 for the next exam? Or just the ones discussed in lecture and the ones in our homework?

Nicole Jacobs 1C

Hi, what sections in the book will the lecture on Wednesday 11/22 cover? I would like to review it on my own since my flight home is that Tuesday before.

Nicole Jacobs 1C

another thing to add is that sigma bonds can rotate and pi bonds cannot rotate. if pi bonds rotate, then they will break, causing a chemical reaction

Nicole Jacobs 1C

can you always use the trick that Lavelle was saying where if water would want to bond on different locations of the molecule, then the molecule is polar for every compound?

Nicole Jacobs 1C

Hi, my TA told our discussion that we only need to know that S does not have any nodes but P does have a node, which is an area of zero electron density. He said that is all we need to know for this class.

Nicole Jacobs 1C

Hi, my TA told me that we will be given the polyatomic ion's molecular formula if we need to use them on the test!

Nicole Jacobs 1C

For the midterm, will we be expected to write the compounds/ions given the written name or will the molecular formula of compounds/ions be given to us? (I mean like will we be given just sulfate ion, or will be told that a sulfite ion is SO3^2-?)

Nicole Jacobs 1C

I think the shielding refers to the reduced affect of the nuclear charge, meaning when there are electrons in an inner shell, the outer shell electrons experience less than actual nuclear charge because electron repulsions work against the pull of the nucleus

Nicole Jacobs 1C

Is there a website or place where I can look at previous midterm problems to prepare for our midterm next Thursday?

Nicole Jacobs 1C

Electrons make the atom bigger because they increase the number of shells the atom has. So losing electrons (becoming cation) would mean you are reducing the number of energy levels and therefore decreasing the size of the atom. Vice versa, since an anion is gaining electrons, it has more shells tha...

Nicole Jacobs 1C

It says on his website that the test will only cover to the end of chapter 1 and the entire chapter 2

Nicole Jacobs 1C

My TA told our discussion to use the exact number of sig figs given to you on Lavelle's formula sheet when solving problems with constant. He told our class not to round them, but rounding will not make a huge difference in your answer if you do every thing else correctly.

Nicole Jacobs 1C

I think he meant electron density distribution but I'm not 100% sure

Nicole Jacobs 1C

Haha it autocorrected mnemonic to pneumonic my bad

Nicole Jacobs 1C

You can remember it by the pneumonic:
Raul's Mother is Visiting Uncle Xavier's Garden
Radio, Microwave, Infared, Visible, UV, X-ray, Gamma Ray
This follows the electromagnetic spectrum in order from decreasing wavelength (and increasing frequency).

Nicole Jacobs 1C

The energy levels are discrete amounts of energy that the electron jumps to when it gets excited from that specific amount of energy. When the electron moves to a higher energy state, it becomes unstable, and emits the energy it just received to return back down to its stable ground state. The Balme...

Nicole Jacobs 1C

When a problem is asking for X amount of an element, and that element seems to often occur in a pair (e.g O vs O^2), if the problem doesn't specify, do you solve for the amount as the single element or in a pair? Or does it not matter? Hi, I think for these types of problems, if it is a common diat...

Nicole Jacobs 1C

I get confused with sig figs when there are zeros. For example, if the number is 0.020, is there 2 or 3 sig figs? This example would only have 2 sig figs because only the trailing zeros are significant if they are after a decimal point. Any leading zeros before a non-zero number is not significant,...

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