CHEMISTRY COMMUNITY

Nhan Nguyen 2F

Kinetically controlled rxn has lower Ea than thermodynamically controlled rxn at higher speed and higher collision frequency as seen in pg 644.

Nhan Nguyen 2F

You can tell that this is an oxidation reaction:
I- has an oxidation state of -2
I3- has oxidation of -1 because taken as a whole molecule, each I atom has -1/3 charge

Nhan Nguyen 2F

Standard cell potential does not change because it is already calculated from standard conditions (Also! It's an intensive property since it's independent on the amount of substances). However, Ecell can change because it's dependent on the changes in the amounts of substance you have. If you have a...

Nhan Nguyen 2F

What do you call a tooth in a liter of water?
.
.
.
.
.
.
.
A one molar solution

Nhan Nguyen 2F

zero order= neg slope
1st order= neg slope
2nd order= pos slope
These are taken from the plots of time vs [A], ln[A], 1/[A] (for the 0th, 1st, and 2nd orders respectively)

Nhan Nguyen 2F

Reaction rate is temperature-dependent: Raising the temperature will increase collisions of the molecules, therefore increasing the rate constant (fast reaction).

Nhan Nguyen 2F

Conservation of anything implies that it cannot be created nor destroyed. However, Entropy is not conserved because it's something that is generated from the "disorder" of systems. Also note that the second law of Thermodynamics states that entropy within an isolated system will keep incre...

Nhan Nguyen 2F

It's actually 10= e^-(deltaG1)/RT divided by e^- (deltaG2 /RT) because 10=k1/k2
When e^x/ e^y, it becomes e^(x-y)

so then it's e^(-deltaG1 + deltaG2 /RT)

Nhan Nguyen 2F

If you increase or decrease a concentration and its rate of reaction also increases or decreases at the same rate, you have a first order reaction

Nhan Nguyen 2F

The order of reactants predicts how many molecules collide together within a reaction. From the order of reactions, you can also figure out whether the concentration of a substance plays a big role in the reaction rate. They allow conclusions to be drawn about the reaction mechanism, and may help to...

Nhan Nguyen 2F

hmm Interesting question! Collision frequency deals with an average rate at which 2 molecules colliding each other within a definite space (this is to help predict the average number of collisions that happen) I found this website online that talks more in depth into collision frequency if you wanna...

Nhan Nguyen 2F

Side note: you can add H3O+ (instead of H+) to acidic solutions that needs an O

Nhan Nguyen 2F

The reaction rate depends only on concentration of reactants because the initial rate is the maximum rate where few products are being produced (it's easier to study only the forward/irreversible reaction) Also note that the rate of reaction depends on: constant k, concentration of Reactants, and or...

Nhan Nguyen 2F

A negative order implies that the concentration appears in the denominator of the rate law.

Nhan Nguyen 2F

Gibbs free energy is a state function, which means that it takes in account of only the initial and final states of the system. Because it's a state function, we can assume that deltaGs of 2 half reactions can be added together to form the deltaG of the final reaction.

Nhan Nguyen 2F

F, because we don't necessarily have to have a temperature change when having an exothermic process. This is seen in phase changes where temp stays constant, but heat is still transferred.

Nhan Nguyen 2F

Removing heat, in this case, doesn't have to change the temperature. If you look at the phase transition graph, you can see that temperature does not change during phase changes (e.i solid melting or liquid vaporizing). Freezing water would be an exothermic process but during the time that the phase...

Nhan Nguyen 2F

For Temperature-dependence entropy,
Cv is used when there is constant volume and changing temperature and the equation you would use is: ΔS = n(Cm,v)ln(T2/T1)
Cp is used for constant pressure and changing temperature and the equation you'd use is: ΔS = n(Cm,p)ln(T2/T1)

Nhan Nguyen 2F

It only states "nitrogen gas" without giving any amount of mols, so I think you can just use 1 mol for that one

Nhan Nguyen 2F

Hmm I do not think it would be on the midterm

But it's related to ΔS = qrev/T in which you would replace qrev with qirrev

the inequality is: ΔS >= qirrev/T

Nhan Nguyen 2F

Lower dipole moments mean that molecules are able to move more freely as opposed to being held tightly by stronger dipole moments. Moving freely= more positions can be occupied --> higher residual entropy

Nhan Nguyen 2F

Potential energy, in chemistry, is referred to as energy that can be able to convert to other forms of energy (ex: kinetic) PE id shown when a ball is on the top step of the stairs, accumulating a high potential energy up there due to its location. The ball only needs a soft push to have it rolling ...

Nhan Nguyen 2F

Gibbs Free Energy is the energy available to do work and the equation associated with it is: △G = △H – T△S in relations to enthalpy, temperature, and entropy Because most reactions occur in constant pressure and Temperature, scientists like using Gibbs when △G = 0: the system is in equilibrium when ...

Nhan Nguyen 2F

From my notes, I have
W = 2^N where N is the number of particles

Nhan Nguyen 2F

I believe for the purpose of the class, they might tell you whether it's reversible or not and you'd plug in the associated equation. But maybe this link can help you in identifying some of the common example processes of each http://www.idc-online.com/technical_references/pdfs/mechanical_engineerin...

Nhan Nguyen 2F

If no preference stated, I think we should use Kelvin since it's more applicable to a lot of thermodynamic problems.

Nhan Nguyen 2F

Delta U (change in internal energy)= q (heat) + w (work)
It said the piston is doing the work of 340 KJ ONTO the gas in the system.
Since we're focusing on the gas, this means that the gas is receiving positive work done to it (+340 KJ)
so, U= 524 KJ heat + 340 KJ work = 864 KJ

Nhan Nguyen 2F

Systems at equilibrium are reversible processes. Imagine you have a gas of 4 atm INTERNAL pressure in a container + a piston pushing down on it with 4 atm EXTERNAL pressure. Since both pressures are equally putting force against each other, the system can't expand much. With that, the changes in V s...

Nhan Nguyen 2F

Can someone explain to me why we use PV=nRT for this problem? I'm just a little confused on when we can use the ideal gas law. Thank you

Nhan Nguyen 2F

Reversible processes are idealized as being fast and efficient. They have more external pressure pushed upon them. Therefore, they perform really slow in transforming all heat into work (constantly maximizing work). However, no real processes are reversible since it just takes way too much time. We ...

Nhan Nguyen 2F

Energy is transferred, but the amount of mercury (matter) is still the same. Closed systems are involved in only heat exchange with the surrounding.

Nhan Nguyen 2F

R is the gas constant which is 8.3145 J/ K * mol or 0.08206 L * atm/ (k* mol) depending on the units the questions give you

Nhan Nguyen 2F

I would keep them together so that it's easier to see the type and amount of ligands you have bound to a metal.

Nhan Nguyen 2F

Oxyacids are just acids that contain Oxygen. Page 477 will show you a whole list of them.

Hope this helps!

Nhan Nguyen 2F

Chromium has oxidation numbers tied next to it. For example, Cr3+ would be Chromium (III)

Nhan Nguyen 2F

Hi,
It's because cyanido is a ligand and cobalt is a metal. You'd put the ligands in ABC order, but metal you put at the end with oxidation numbers.

Nhan Nguyen 2F

I'm wondering the same thing...maybe on the test, put Sodium diaquabis(oxalato)ferrate(III) since it follows the rule more? What does everyone else think?

Nhan Nguyen 2F

For expanded octet, you should know that elements in period 3 and above are able to have beyond a full set of valence electrons and that Boron has less than an octet.

Nhan Nguyen 2F

I think that 2sp--> linear, 3sp^2 ----> Trigonal Planar, 4sp^3----> Tetrahedral, 5sp^3d ----> Trigonal bipyramidal, 6sp^3d^2 ----> Octahedral

Nhan Nguyen 2F

If the complex negative charge, -ate is added to the end of the metal's name (in this case Co).
As for Cyanido vs cyano, they're the same ligand, so I think you can use them both. Correct me if I'm wrong, but hope this helps!

Nhan Nguyen 2F

I believe the rule meant that while the electron density in the area of the multiple bonds is greater than a single bond's, the area/region would still be the same.

I'm also wondering the same thing for Rakhi's 2nd question

Nhan Nguyen 2F

Ionic bonds form when the difference in electronegativity is large between the molecules. However, sometimes the electronegativity difference in molecules is not large enough to form ionic bonds. The electrons are not shared equally, creating partially negative and partially positive regions. These ...

Nhan Nguyen 2F

To elaborate on Christian's post,
Triple bonds are strongest, followed by doubles and single bonds. Bond length decreases as bond strength increases. Shorter bond lengths do not need to be long because attractions pull electrons closer.

Nhan Nguyen 2F

For better understanding,
We know E is an atom that is able to take in more than 4 bonds (as we can see in the structure). Atoms in period 3 or later can accommodate for additional electrons (more than the full 8 electron set!)

Nhan Nguyen 2F

Hi, I have a different answer for this problem. 1) So I started with Argon since it was in brackets [] 2) the next configuration is 3d10, so I counted 10 elements after Argon--> landed on Nickel 3) the last configuration is 4s2, so I counted 2 more after Ni --> landed on Zinc So zinc is my answer

Nhan Nguyen 2F

Hi!
I can't quite grasp the concept of this. Can someone clearly explain why the Heisenberg equation is delta X and P is greater than or equal to H bar? Why is it greater than/ equal to?

Nhan Nguyen 2F

Hi, You can imagine excited electron movements similar to when you pluck guitar strings. When you pluck on a string, the string vibrates, creating an image of rapid side-to-side movements. This is like electrons in which they move up an energy level and then back down to its original state - this pr...

Nhan Nguyen 2F

Hi, The principle quantum number (n) is what determines the size of an orbital. Based on my understanding, more energy is needed to be absorbed to excite an electron from the orbital that is closer to the nucleus (n=1) to a farther orbital (n=2). Thus, orbitals for which n=2 is larger than n=1 becau...

Nhan Nguyen 2F

I agree with Deborah. It might be helpful to know the general area like Radio<< microwave<<infrared<< visible<<UV<<X-ray<<gamma rays *Radiowaves have low frequency/longest wavelength *Gamma rays have high frequency/ shortest wavelength I found this funny acronym if you guys would like t use it: Rabb...

Nhan Nguyen 2F

Piggybacking on the first respond-- But yes, photoelectric experiments typically use ultraviolet light and sometimes visible light (if used on alkali metals). This is because the photons of UV lights have enough energy to be able to break the binding force of electron emission from a metal's surface...

Nhan Nguyen 2F

The Avogadro's number is 6.022 x 10^23 and this number is what defines 1 mole. A "Mole" is similar to the use of "dozen" (12) or "gross" (144). All of these numbers are used to group a certain amount of stuff (such as electrons, atoms, molecules,etc). ** I'd like to not...

Nhan Nguyen 2F

Hi, So the picture illustrated that there are 9 galliums atoms on the left and it is asking how many Astatine atoms should be put in to balance out the scale. 1) Given n= # of moles, M= molar mass the equation should be n(1)xM(1) = n(2)xM(2) 2) Find the molar mass of Ga ---> 69.7 g/mol Find molar ma...

Search found 52 matches