CHEMISTRY COMMUNITY

Laura Riccardelli

They gave the point to both A and B and A was correct because the C8H18 is such a massive molecule that it will have a higher entropy.

Laura Riccardelli

Because the disorder of the container went up as is shown by the increase in the number of moles and the change in phase from solid to liquid and gas.

Laura Riccardelli

The higher the standard standard reduction potential the better oxidizing agent and the more likely the reaction is to be reduced and the more negative the stanbdard potential the better a reducing agent and the more likely to be oxidized.

Laura Riccardelli

And you can get these fom the equations for 0, 1st, and 2nd odrder reactions that are on the equations sheet.

Laura Riccardelli

I think your reasoning is correct. Maybe the questions should have been more specific.

Laura Riccardelli

I think you can use mass because you would be dividing by the same number of L on both sides so they would cancel anyways.

Laura Riccardelli

Would we need to know if the reaction is proceeding in the forward direction based on the k value?

Laura Riccardelli

In part c of this peoblem it asks what is unique about it. Could someone explain this to me.

Laura Riccardelli

In problem 14.97 they want you to calculate the ka value. How is this differnt from regular k?

Laura Riccardelli

This is a really good question!

Laura Riccardelli

I think that it means that the ion beocme more neutral.

Laura Riccardelli

That means that it will become less charged or closer to a neutral charge.

Laura Riccardelli

This is an exccelent question. I was wondering the same thing.

Laura Riccardelli

I am confused on how cr 3+ is the reducing agent and MnO is the oxidizing agent for this reaction. It seems like it should be opposite.

Laura Riccardelli

The n value is found by the diffeence in the number of moles on the product and reactant side.

Laura Riccardelli

I think that they would tell us if it was not obvious what the system and surroundings are.

Laura Riccardelli

I used the equation delta S=nRTln(P1/P2) since the pressure is changing and these is a constant temperature. You can substitute (T2/T1) for (P1/P2) using the ideal gas law.

Laura Riccardelli

My understanding is that if the delta G is negative then it is a spontaneous favorable reaction and will proceed toward the products.

Laura Riccardelli

Also, since delta U is zero then we also know that q=-w.

Laura Riccardelli

I think because it does not specify you don't need to worry about moles.

Laura Riccardelli

If you look at problem 9.19 they give you the Cp for liquid and vapor water so I am assuming that the equation can be used for nay state as long as they give you the Cv/Cp for the problem.

Laura Riccardelli

Also,most biological systems are irreversible because that needs less work then reversible expansion.

Laura Riccardelli

I am confused in this homework problem where the N2 value goes because it is not in the final equation when using Hess's Law. I know that the delta H of N2 is era but it does not show up in the final equation with the actual molecules.

Laura Riccardelli

I think that the reversible problems occur in heat reservoir so they have a constant temperature all the time.

Laura Riccardelli

In this problem the you have to use the equation H= sum of n(Hf) of products -sum of n(Hf) of reactants but the solution manual seems to have these the products being subtracted from the reactants. How is this correct? Am I using the wrong formula?

Laura Riccardelli

Why is it that w=0 is always true in an adiabatic system because I thought that work could be done to or by the system as long as no heat was lost or gained from the soundings?

Laura Riccardelli

I believe that you should use the equation q=(M)(change in T )(specific heat capacity) the solution maple also has you using the equations Cp,m=(5/2) R to find the specific heat capacity for the ideal gas at an constant pressure and Cv,m= (3/2) R for the molecule at a specific volume. I am confused ...

Laura Riccardelli

I found in question 8.55 that the O2 term was multiplied by 1.5 to cancel out but the rest of the equation remained the same. How is this allowed?

Laura Riccardelli

I found that equation 55 starts with the problems that my TA and Lavelle has referenced

Laura Riccardelli

In question 8.55 in the answer manual, in order to get ride of the 1.5 O2 in the first equation to end up with the second equation the O2 molecules in the second equation is made into 1.5 O2 as well but nothing is changed in the rest of the equation. I am wondering how you are able to change the O2 ...

Laura Riccardelli

Lavelle said we should complete the acid run homework problem but I did not find it. Do you know which problem he is referring to?

Laura Riccardelli

If the shape of the molecule is trigonal bi-pyramidal do the dipole moments cancel because their are 5 binding sites?

Laura Riccardelli

How do you know if a molecule is mono, bi, tri, tetra, or hexadenate simply by looking at the molecular name?

Laura Riccardelli

The problem has a graph and asks you to write a balanced chemical equation for it but gives no coefficients. How do you write the balanced equation?

Laura Riccardelli

Look at the base equations H2 + Cl2= 2HCl and 2BrCl=Br2 = Cl2 which have corresponding K values and multiply those K values together.

Laura Riccardelli

Can someone explain the difference between Q and K?

Laura Riccardelli

The orbitals that are not a part of the hybridized orbital as will form pi bonds.

Laura Riccardelli

Is a N2 molecule covalent?

Laura Riccardelli

And likewise, a molecule that needs a lone pair to be stable would be a Lewis acid. You can think about OH- and H+ as examples. H+ is the acid because it needs another election to be stable while OH- is a base because it can donate an electron in order to be stable.

Laura Riccardelli

In problem 3.61 b, how do we know that "I" has to have 12 electrons and does not follow the octet rule?

Laura Riccardelli

In problem 3.39, how do we know that some of the Lewis structures should have double bonds such as in c and some should only have single bonds such as in a and b? Does this have to do with the Formal Charge?

Laura Riccardelli

Which elements are we expected to be able to name in the ground state?

Laura Riccardelli

hen you are writing the electron configuration for elements in order to find the unpaired electrons, how do you know which quantum number (ex: 4f, 3p, 2s) to continue counting up with after the core element is used form the Nobel gases? Do you simply have to count all the quantum numbers out and the...

Laura Riccardelli

I was also a little confused by this question but I believe that because it is talking about "d" orbitals which can have 5 different lobes each lobe can have a different sub-shell value so their would be 5 possible ml or sub-shell values.

Laura Riccardelli

Will Lavelle ever use the "h" that stands for another value other then Planks constant that the solution manual uses in the equation?

Laura Riccardelli

How often will be asked to apply Rydberg's equation in this class?

Laura Riccardelli

In the answer to question 1.23 how did you get the equation lambda=(hc)/E from the two equations E=hv and c=lambda?

Laura Riccardelli

When you write the answer to question 9 do you follow the number answer with "formula units" or do you leave it blank?

Laura Riccardelli

The problems that can be found in the first three modules on the class website are also a great way to study for the test.

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