CHEMISTRY COMMUNITY

Jack Riley 4f

K=(k'/k) is the relationship between equilibrium constant and rate constants

Jack Riley 4f

An example is a neuron and its action potential. It is at equilibrium, but when it receives a signal, Na+ ions rush in causing it to veer from equilibrium until the K+ ions rush out, returning it to equilibrium.

Jack Riley 4f

It may matter conceptually, but I doubt quantitatively. Poisoning a catalyst is to cause it to lose its function.

Jack Riley 4f

It helps us determine which collisions occur with enough energy to overcome the activation energy. This helps us determine A in the Arrhenius equation

Jack Riley 4f

probably not. the calculations should be sufficient

Jack Riley 4f

you look at the graph and compare it with the 3 possible orders to determine which one best fits the graph shown

Jack Riley 4f

Q is a ratio so it has no units because they cancel out

Jack Riley 4f

It is more precise for that specific moment in time

Jack Riley 4f

the TA's have said that the book writes it in different format sometimes but that we should stick to what we were taught in lecture and we'll be ok

Jack Riley 4f

It is a list of reduction half reactions

Jack Riley 4f

It's a common electrode because it is inert and doesn't interfere with the redox reaction

Jack Riley 4f

It keeps the 2 solutions neutral so electrons can continue transferring

Jack Riley 4f

the oxidizing agent gains electrons and the reducing agent loses electrons

Jack Riley 4f

it is used to find the nonstandard cell potential

Jack Riley 4f

You need a metal to conduct the electrons and platinum is inert and doesn't interfere with the redox reaction

Jack Riley 4f

It will probably include Gibbs free energy and all the material that we get through this week (electrochemistry)

Jack Riley 4f

My book also says 150 degrees celsius which matches up with the 423 K

Jack Riley 4f

when talking about delta T then yes it is ok because they are the same in that respect. However, when doing calculations with T you should convert to K because most R values are given with K as the unit

Jack Riley 4f

Just look at the units needed in the problem and choose the R with those units same units

Jack Riley 4f

I have found the UA sessions to be very helpful so to anyone who is struggling go to as many as you can!

Jack Riley 4f

Cp = 5/2R and Cv = 3/2R both apply to monoatomic gases. Cp is for constant pressure and Cv is for constant volume

Jack Riley 4f

the change in internal energy is 0 at constant temperature, however the internal energy itself is not necessarily 0 at constant temperature

Jack Riley 4f

delta S of the surroundings does equal 0 because it is free expansion, but delta S total must still increase so that only leaves delta S of the system to contribute to this. Thus, delta S total = delta S system =/= 0

Jack Riley 4f

4.17 A technician carries out the reaction 2 SO2(g) 1 O2(g) S 2 SO3(g) at 25 8C and 1.00 atm in a cylinder fitted with a piston and maintained at constant pressure. Initially, 0.030 mol SO2 and 0.030 mol O2 are present in the cylinder. The technician then adds a catalyst to initiate the reaction. (a...

Jack Riley 4f

4F.13 Use data in Table 4C.1 or Appendix 2A to calculate the entropy change for (a) the freezing of 1.00 mol H2O(l) at 0.00 8C; (b) the vaporization of 50.0 g of ethanol, C2H5OH, at 351.5 K.

How would you solve this?

Jack Riley 4f

we won't actually have to do this

Jack Riley 4f

the only calculus so far is w=integral(PdV)

Jack Riley 4f

the equation for an isothermal, reversible expansion is w=-nRTln(V2/V1)

Jack Riley 4f

deltaU = q + w so you can change it by adding heat or doing work

Jack Riley 4f

at 25 degrees celsius, water is a liquid, so I would assume you use the liquid form.

Jack Riley 4f

They're still available throughout the quarter I have been told

Jack Riley 4f

A calorimeter is used to measure heat of a rxn

Jack Riley 4f

you can still pick them up week 4 so don't worry

Jack Riley 4f

the enthalpy of sublimation is the sum of the enthalpy of vaporization and fusion

Jack Riley 4f

It helps mix together the solvent and solute so the rxn can go to completion

Jack Riley 4f

If K < 10^-3 then you are able to approximate.

Jack Riley 4f

You can calculate Kp from Kc by using Pv=nRT if given concentrations and enough info. ICE tables are also used for partial pressures as well, though.

Jack Riley 4f

If delta H is positive, then it is endothermic

Jack Riley 4f

Just follow what he tells us to read on the syllabus.

Jack Riley 4f

Steam has more heat energy due to the fact that that energy was inputted in order to vaporize the H2O.

Jack Riley 4f

I would say yes because partial credit is huge on Lavelle's tests so you should write it out just in case.

Jack Riley 4f

Liquids and solids cannot be dissolved or have their pressures changed in solution so they are not factored in when calculating K.

Jack Riley 4f

Strong acids and bases completely dissociate in solution while weak acids and bases only partially dissociate.

Jack Riley 4f

If you increase N2, then H2 will decrease because the reaction will move toward the right.

Jack Riley 4f

The closer K is to 1, the more stable the reaction is because then the conc of reactants and products is almost equal and neither is favored

Jack Riley 4f

It would have no effect because solids are not part of the equation

Jack Riley 4f

K is the general equilibrium constant while Kp refers to the equilibrium constant when using partial pressures.

Jack Riley 4f

number of moles

Jack Riley 4f

K is the general equilibrium constant while Kc specifically refers to the equilibrium constant of molar concentrations

Jack Riley 4f

Do every hw problem on the syllabus

Jack Riley 4f

acetic acid has a less stable conjugate base so it is a weaker acid.

Jack Riley 4f

It is a tetrahedral molecule, so the dipoles only cancel out when all 4 atoms are the same.

Jack Riley 4f

It depends what it is reacting with. In an acidic solution, it acts as a base and vice versa

Jack Riley 4f

You need to check what is bonded to the oxygen. If it is a metal, then it is basic. If it is a nonmetal, it is acidic. The metalloids can form amphoteric oxides.

Jack Riley 4f

Radicals only exist when there are an odd number of valence electrons. None of these examples have an odd number so none are radicals

Jack Riley 4f

oxidation number is the charge of the central transition metal ion. Coordination number is the number of bonds the central ion forms in the compound

Jack Riley 4f

There are 3 nitrogen atoms in that molecule so it can bind on the central ion at 3 binding sites. Thus, it is tridentate

Jack Riley 4f

Technically all reactions should have equilibrium arrows. However, for strong acids and bases, the reverse arrow is so small that it is omitted

Jack Riley 4f

polydentate refers to a ligand that binds to the central ion at more than one binding site.

Jack Riley 4f

Those are the 3 most common shapes that coordinate compounds will take.

Jack Riley 4f

Because there are lone pairs on both sides, the effect of both is equal and opposite so the bond angles are just 90 and 180

Jack Riley 4f

The question only asks about interactions between SO2 and other SO2 molecules. Thus ion-dipole and dipole-induced dipole interactions do not occur.

Jack Riley 4f

The best way is to look at the structure

Jack Riley 4f

It is polar because it has a bent shape, thus there is a net dipole toward the O atom

Jack Riley 4f

It is always negative because these interactions are attractive. Ep increases with polarizability and decreases as distance increases.

Jack Riley 4f

Dipole moments occur in molecules whose atoms have a high enough difference in electronegativity to create partial positive/negative charges.

Jack Riley 4f

Breaking bonds always requires energy while forming bonds releases energy

Jack Riley 4f

Test 2 is starting Tuesday, Nov 19 in discussion sections

Jack Riley 4f

Electrons are constantly moving throughout an atom so the random dispersion of these electrons leads to London forces forming between atoms and molecules.

Jack Riley 4f

Ep often stands for energy of photon when doing photoelectric problems and for potential energy when in the context of IMFs

Jack Riley 4f

You use Heisenberg's Uncertainty Principle which states m(delta v)(delta x) > h/(4pi). Use this to solve for delta v with what you know.

Jack Riley 4f

The charge goes toward the more electronegative atom.

Jack Riley 4f

It wouldn't. SO3 would be most stable with 3 double bonds

Jack Riley 4f

I'm not totally sure, but on the first outline it does say naming is a skill we should be able to do.

Jack Riley 4f

For a) the O must have the +1 charge because this is the only way both the N and the O can have a full octet. If the N had the +1 charge it would only have 6 valence electrons, not 8.

For c) the same thing applies.

Jack Riley 4f

The above formula is correct and when I calculated it out I got n=6 as my answer. Maybe you just entered it into your calculator wrong

Jack Riley 4f

resonance hybrids are all the different ways to draw a molecule that has resonance.

Jack Riley 4f

manganese has an electron configuration of [Ar] 3d5 4s2 so the electrons in the outermost shell are the 4s2 electrons. This means manganese has 2 valence electrons.

Jack Riley 4f

Dr. Lavelle mentioned this in class, but basically tungsten is an exception to the exception.

Jack Riley 4f

Delocalized bonds are bonds that appear in some resonance forms. Basically, it describes the fact that some electrons are not specific to a particular bond or atom. This is due to resonance and is experimentally proven by the fact that all bonds in a molecule with resonance have a length somewhere b...

Jack Riley 4f

The homework for this week just needs to be any 5 different questions from the quantum world sections

Jack Riley 4f

In the p-subshell x, y, and z are used to refer to the 3 different orbitals that exist in this sub shell. Each is oriented along one of the axes, thus they are labeled px, py, pz.

Jack Riley 4f

There are orbitals past f, such as the g orbital for example. However, this orbital is very unstable. For this class, we only need to know how to use the s, p, and d orbitals and know of the f orbital.

Jack Riley 4f

the ground state of an ion or atom simply refers to the lowest energy state of said ion or atom.

Jack Riley 4f

you must first find the wavelength of krypton-86 radiation. To do this, divide 1 meter by 1650763.73 to find the length of the wavelength. This gives you a wavelength of 6.06x10^-7 or 606 nm. This is visible light. To find the energy we must use E=hv=(hc)/(lambda)=3.28x10^-19

Jack Riley 4f

Each metal has a specific work function so for all the problems that we will need to know it we will be given it.

Jack Riley 4f

it means proportional to

Jack Riley 4f

EM radiation doesn't change speed. Light always travels at 3.0x10^8. This is why the equation c=(lambda)v is viable.

Jack Riley 4f

you use the Rydberg formula with the Constant as 3.29x10^15 because that gives you frequency. After finding the frequency, plug it into c=(lambda)v to find lambda=486 nm. From that, you can check in the table and see it is in the Balmer series and 486 nm is at the higher end of visible light so it i...

Jack Riley 4f

To find n2 you need to use Rydberg's Formula. First you must find frequency using v=c/lambda with lambda=102.6 nm given. Then use Rydberg's formula and solve for n2

Jack Riley 4f

When he introduced the speed of light in class he used 3.00x10^8 m/s so I think that's what we should use.

Jack Riley 4f

Photons don't necessarily have "size" as we think about it on a macroscopic scale. They are just packets of energy.

Jack Riley 4f

To determine if an ion is a spectator ion you just need to look at the product that is stated in the problem. In this problem the product is copper(ii) hydroxide so you know that the sodium and nitrate are the spectators. Because they are spectators, they don't need to be balanced because they exist...

Jack Riley 4f

By using E=hv we are finding the frequency of the photon, so we need to worry about the sign of the photon's energy, not the electron's. Because the electron is emitting energy, its sign is negative and so the energy of the photon must be opposite this (positive).

Jack Riley 4f

light has wavelike properties on a macro scale

Jack Riley 4f

I'm guessing we should go with what professor Lavelle says and follow his lead in using 6.022 instead of 6.0221. Although, I doubt it's significant enough that it will make much of a difference.

Jack Riley 4f

It doesn't matter that they are different substances because the units of each are still in moles. So you need to take into account the molar mass of CuSO4.5H2O instead of just CuSO4.

Jack Riley 4f

"Formula Units" and "Molecules" are basically the same thing. The only difference is that formula units refer to ionic compounds while molecules refer to covalently bonded elements.

Jack Riley 4f

Titration is the process of slowly adding one solution of a known concentration into another solution with a known volume. So basically any of the homework problems that we have completed in fundamentals L is an example of titration.

Jack Riley 4f

You only assume that the sample mass is 100g to make the calculations easier. Because percentages are on a scale of 1-100, assuming that the sample mass is 100g allows you to skip a step and just convert the percentages to masses by changing the units from a percent sign to grams.

Search found 100 matches