CHEMISTRY COMMUNITY

John_Richey_4A

For this question it has 1.0 NiSO4 solution was electrolyzed by using inert electrodes. It asks for the cathode reaction and the anode reaction, and I'm not sure how they chose them.

John_Richey_4A

For this question it has you analyze a concentration cell of Ag--> Ag+ +e- where the anode has a concentration of .005 mol/L of Ag+ and the cathode has a concentration of .15 mol/L, and it asks what is the maximum work this cell can perform per mole of Ag. I used the Nerst equation and I keep coming...

John_Richey_4A

For this question it says to find the redox reaction between potassium permanganate and Iron(II) chloride, I used the half reaction Fe2+ + 2e---> Fe, but this is wrong for two reasons. 1. Iron is supposed to be the anode not the cathode and 2. The half reaction involves an Fe3+ species. I have no cl...

John_Richey_4A

How are we supposed to know for this question that the half reactions of NiSO4 are Ni----> Ni2+ and the one involving water? Why isn't the other half reaction involving the sulfate?

John_Richey_4A

For part A it in the cell diagram it has HCl so I would assume we need a half reaction that involves HCl however I cannot find one in the appendix

John_Richey_4A

For This question I keep getting slightly different answers than whats in the back of the book. For part b I got 801 minutes by seeing that since the halflife was 247 minutes, I found how many half lives there it would take to get to 10% which I found to be 3.25 and I multiplied this by 247. For par...

John_Richey_4A

I have basically no clue on how to do this question, or where to start for that matter.

John_Richey_4A

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John_Richey_4A

For this question we need to use the Arrhenius equation, but I'm unsure on how to use it here. Whenever I divide the first equation by the other I get .98 which is way off.

John_Richey_4A

How are we supposed to know which one will be the reducing agent and the oxidizing agent when both elements are listed in ox/red. Please do not give the answer " the one that is reduced gains electrons," or " the one that is oxidized loses electrons."

John_Richey_4A

That is the definition of reduction and oxidation, but doesn't answer my question. When looking at, for example, Ti3+/Ti, and Co2+/Co, how are we supposed to know which one will be the reducing agent and which one will be the oxidizing agent?

John_Richey_4A

When looking at a pair of redox couples how are we supposed to know which one is the reducing agent and which one will be the oxidizing agent in the overall reaction?

John_Richey_4A

For questions like 14.15 where it asks to devise a galvanic cell for equations like (H+) + OH- -> H2O, I don't see any reason why the used the equations for the half reactions that they did. In the appendix I see multiple different equations that involve H+ or OH- so how am I supposed to know that I...

John_Richey_4A

In question 14.25 it asks to list the transition metals in order of increasing strength of reducing ability. How are we supposed to know the relative reducing ability for transition metals? I understand the trend for alkali and alkaline earth metals, but I don't see one for the transition metals.

John_Richey_4A

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John_Richey_4A

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John_Richey_4A

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John_Richey_4A

In question 8.3 they use pascals to find it in Joules and then randomly in question 8.9 they decide that kilopascals times the change in volume equals Joules.

John_Richey_4A

In this question I am multiplying the amount of moles of each substance by the Molar heat capacity and by the change in temperature and I keep coming out with the answer 150 KJ and not 140 KJ and I have no idea what I am doing wrong here.

John_Richey_4A

In question 8.3 you use the conversion of atm into pascals rather than kilo pascals in the final answer, then is question 8.9 they expect you to use the conversion of atm into kilo pascals for that final answer and now I have no clue which one is correct because using either method is going to make ...

John_Richey_4A

In part b I have no clue how they got the heat of absorbed, my answer is 368 KJ because you use 4.1 moles of carbon/ 4 moles needed and multiply that by the standard enthalpy.

John_Richey_4A

For this question I don't know what to do after I found out how many Joules it take for the ice cube to melt. The only equation I can think to do is the specific heat one but that would require me to know the change in temperature which is the point of the question, and considering I don't know by h...

John_Richey_4A

I'm not sure what equation to use for this question because I don't know the specific molar heat capacity of krypton.

John_Richey_4A

I keep getting the work done by the system is 148 KJ which is off by a factor of 10^6, what am I doing wrong?

John_Richey_4A

In this question you subtract the heat increased in the system by the heat absorbed to the system, why is this?

John_Richey_4A

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John_Richey_4A

Could you say J/L instead of bar?

John_Richey_4A

What is work exactly?

John_Richey_4A

-x is just what you subtract from the initial.

John_Richey_4A

How is Le Chatelier's principle applied when another gas in added to a system?

John_Richey_4A

When do we have to use the quadratic equation for ice boxes?

John_Richey_4A

Is delta H positive or negative in the breakdown of halogens like F2 into 2F?

John_Richey_4A

H is the amount of energy in a system plus the product of its pressure and volume, so delta H would basically be how much energy was taken away or put into the system. If its positive that means the system absorbed heat and would always favor the products when heat is added and visa versa for your s...

John_Richey_4A

I'm not sure what I'm doing wrong on this problem but I keep getting .933 for the Kc and not 3.88.

John_Richey_4A

How do we know to use an ICE table in a question?

John_Richey_4A

What is the difference between Kc, Kp, and K (K not referring to the temperature).

John_Richey_4A

Title.

John_Richey_4A

You most likely wont be given momentum, but one of the two parts making up momentum, either m or v.

John_Richey_4A

Why is HF a weaker acid than HCl. I understand it has to do with the electronegativity being higher, but if thats the case, why is HClO a stronger acid than HBrO?

John_Richey_4A

You give the central transition metal an -ate ending when it is the anion of the coordination compound.

John_Richey_4A

I think one of them is just the new naming convention, but I believe we can use either.

John_Richey_4A

All you have to do is is find the mass of one N2 molecule, multiply it by delta v and dela x which in this case is 1.5E-4m. Then you divide the other side of the equation (h/4pi) by that value and you have delta v.

John_Richey_4A

I usually look at the previous tests and do all of the homework problems.

John_Richey_4A

I think on the midterm it even gave all the acid and base information so I think it'll be the same.

John_Richey_4A

Could someone explain the concept of chelation and how to figure out if a molecule is chelating?

John_Richey_4A

How do you find what this is?

John_Richey_4A

How can you tell which ligands can be polydentrate, and by how much?

John_Richey_4A

Hydrogen bonds are bonds outside of the molecule itself, so multiple molecules can be hydrogen bonded but still be different molecules. If something is covalently bonded, that results in an entirely different molecule.

John_Richey_4A

Only the elements past period 3 can have more than the octet, excluding boron. In those cases it's more important to have the most stable molecule, if it isn't an element in or past period 3, focus on filling the octet.

John_Richey_4A

You're going to need to need to know which elements result in polar or non polar compounds.

John_Richey_4A

When I see HBr I anticipate its going to be ionic because its a large elctronegativity difference. Why am I wrong?

John_Richey_4A

What is it?

John_Richey_4A

All a melting point is, is vibrating the atoms enough so they can roll past each other, if they're bonded to each other this inhibits their ability to roll past each other.

John_Richey_4A

You just say its one intermediate bond.

John_Richey_4A

Just look up which has a higher and lower electronegativity, and if they have a large difference, it's ionic.

John_Richey_4A

It's a result of random movement of electrons, sometimes they just so happen to be more concentrated on one side, this affects electrons in all nearby atoms.

John_Richey_4A

Where is the midterm going to be held?

John_Richey_4A

It just means valence=how many covalent bonds an atom can make.

John_Richey_4A

They basically do that in real life. Ionic compounds aren't "molecules" that are bonded together, it's just really intense static.

John_Richey_4A

Because those electrons aren't involved in the bonding.

John_Richey_4A

He didn't say anything about so I doubt it, it even said in the book knowing anything past p would be tedious or something along the lines of that.

John_Richey_4A

It said in the chapter that if you evaluate the Schrodinger equation for an s shell, it will have a non-zero probability density in the nucleus because it doesn't have an angular momentum, l, to repel it.

John_Richey_4A

Is there a general rule of thumb how many valence electrons transition metals can lose?

John_Richey_4A

I don't think its due to the fact that it exhibits constructive interference rather than destructive interference specifically, rather it's highlighting the point that it exhibits interference in general which is a wave-like property. The conclusion that it has a wave-particle duality would've been ...

John_Richey_4A

Because it is energy emitted which results in an energy state more negative than when it hadn't emitted a photon.

John_Richey_4A

How would you tell the extent of change in an electrical field at a given point according to a decrease in frequency?

John_Richey_4A

It just arbitrarily asks, find what the mass of the metal sulfide would be, its not related to the previous measurements, but you should be able to find it if you know the mass of sulfide.

John_Richey_4A

He answered this question kind of vaguely, but it seemed like he was saying that you don't need to at this moment. There are also compounds like the osmium one that could be basically anything, and we haven't covered anything pertaining to that anyways.

John_Richey_4A

Yes they can because every molecule has a molar mass that can be calculated, and thus needs to have a number of moles to calculate that.

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