CHEMISTRY COMMUNITY

Shrayes Raman

standard gibbs free energy is defined for a given reaction at standard conditions but gibbs free energy is just a general measure of reaction sponteniety.

Shrayes Raman

I am pretty sure they are the same thing. There is a difference between galvanic vs electrolytic cell.

Shrayes Raman

equation 1 del G = -rtlnK equation 2 del g = -nFe*

Shrayes Raman

Mass doesn't affect the overall reaction.

Shrayes Raman

A special type of electrode not made of metal. i think its used in pH meter.

Shrayes Raman

Related by E=E* - RT/fnln(conc cathode/conc anode) although depends on problem.

Shrayes Raman

Know how the first order second and zero order plots look like and how they relate the [a] and time

Shrayes Raman

k' is called "k prime" and refers to the reverse reaction.

Shrayes Raman

Exothermic reactions will have reactants higher than products and vice versa for endothermic.

Shrayes Raman

I don't believe the energy graph necessarily provides information on the slow step but I could be wrong.

Shrayes Raman

Microscopic reversibilty refers to the reactions having the same intermediates in the forward and reverse reactions.

Shrayes Raman

Linear 1/[A] v time but not [A] v time

Shrayes Raman

It will probably best to understand how they are derived as he may ask you that on the final.

Shrayes Raman

Same intermediates in both forward and reverse directions as some reactions will not have the same intermediates one way as another.

Shrayes Raman

I believe you are refering to lower case k so it will increase with temp as more collisions

Shrayes Raman

I believe it is good practice to change to seconds but depends on context.

Shrayes Raman

Initial rates is an experimental technique in which multiple reactions are observed the only difference being initial concetrations.

Shrayes Raman

Plot is linear because reaction rate is constant so linear relationship.

Shrayes Raman

Half life of zero order is[ initial concentration / 2 * k]

Shrayes Raman

A zero order reaction just has a constant and independent reaction rate

Shrayes Raman

First vs second vs zero order laws determine relationship between input and output (input usually being time). first order reactions are natural log relationship, second order are recipricol relationship, and zero order have linear relationship.

Shrayes Raman

, for species in same phase, | for species in different phase, || salt bridge or porous disk

Shrayes Raman

Reduction corresponds to the part of the reactions gaining an electron.

Shrayes Raman

Positive SRP is equivalent to negative delta G so it will be spontaneous.

Shrayes Raman

1 atm and 273.15 K or 0 C

Shrayes Raman

Difference in phase of the species, for instance (aq) vs (s)

Shrayes Raman

I believe you should just know to place the electrodes (anode and cathode) at the ends of the diagram.

Shrayes Raman

Platinum is the best inert conductor so it doesn't oxidize

Shrayes Raman

The Coloumb is equivalent to the charge in an arbitrary number electrons and Ampere is that charge per second

Shrayes Raman

I believe porous disks and salt bridges are notated in the same way as they achieve the same end goal.

Shrayes Raman

Both are aqueous so the convention is to separate by comma

Shrayes Raman

The cell potential is given in reduction form so switch if oxidization is occuring.

Shrayes Raman

Look at both sides of the equation and determine which species is gaining electons and which is losing and that should tell you which is being oxidized and which is reduced.

Shrayes Raman

Electrons need to go back to anode side to maintain reactions.

Shrayes Raman

Depends on the context of the problem, however it should be given (aq) (g) (s) (l)

Shrayes Raman

Half reactions refer to the splitting of a redox reaction into its components based solely on the movement of electrons. A half reaction is balanced when both sides have the same number of electrons.

Shrayes Raman

There are multiple factors that contribute to higher multiple micro states but complexity is one of them. if you increase the number of bonds you are therefore increasing complexity increasing entropy. Although this differs in the case of going from two substances to one larger more complex molecule.

Shrayes Raman

Yes I think so. The Irreversible graph is always straight and the Reversible graph is curved starting at a higher pressure and with a negative slope

Shrayes Raman

In every question in the HW it is stated whether constant pressure or constant volume is occurring. if constant pressure 5/2R and constant Volume is 3/2R

Shrayes Raman

Take the case of a system losing heat q to surroundings at a lower temperature. The absolute value of entropy for Surroundings at lower temperature will always be greater than for the system because the denominator will always be smaller in q/T for same q

Shrayes Raman

Intensive property do not care for quantity. For instance Density is intensive as it will be unchanged regardless of amount of material. This is the opposite for Extensive property such as mass.

Shrayes Raman

Kelvin... The gas constant R is listed in Kelvin so Kelvin is used in equation.

Shrayes Raman

If you look at the graphs in the textbook it is clear that the reversible formula gives much more area and there for a greater value for integral than the irreversible formula which just is a rectangle. It has to do with the math of the curve vs straight line

Shrayes Raman

constant pressure is assumed unless otherwise specified as we have the equation nRT ln(v2/v1) assumes constant pressure

Shrayes Raman

delta u = delta H + work. You can use this relationship to calculate any of the three values in the equation.

Shrayes Raman

If a reaction is exothermic it loses heat to surroundings so the change must be negative. I think you are getting value for calorimeter not system.

Shrayes Raman

I may be misunderstanding your question however you do not need to include bond enthalpies for bonds that are not broken in a reaction, ie 3C2H2 -> C6H6 do not need H - C bond enthalpies because they are not broken

Shrayes Raman

It is flat because the addition of energy as heat into the system causes the substance to fully change phases before increasing the temperature of the substance.

Shrayes Raman

Steam undergo's a phase change thus releasing more energy while water liquid doesn't.

Shrayes Raman

Short answer is the intermediates don't matter as its a state function.

Shrayes Raman

Enthalpy is listed as h as with other examples if it is negative it is exothermic and vice versa

Shrayes Raman

heat released is a factor when calculating enthalpy for a given system.

Shrayes Raman

There is no indication that we would be required to calculate any thing like that so we will need it given to us.

Shrayes Raman

Solid to liquid is relatively low energy but liquid to gas is much higher.

Shrayes Raman

Going up a phase is akin to going up in energy levels so the correlation works both ways.

Shrayes Raman

Combustion is more specific than those general classes of reactions.

Shrayes Raman

Enthalpy would be the same, but the energy is released in different forms.

Shrayes Raman

Steam will have to undergo phase change so it releases much more kJ of energy than liquid which doesn't phase change.

Shrayes Raman

It has to do with state functions and how they relate to enthalpy, as enthalpy is not determined by path taken.

Shrayes Raman

Depends on given info but bond enthalpies method least accurate

Shrayes Raman

Lavelle said that the bond enthalpies is the easiest but least accurate. Therefore I feel like he doesn't want us to use that.

Shrayes Raman

Heat is the energy that is released while work is the amount energy required to perform a certain task.

Shrayes Raman

Q is basically calculated the same way as K but can be calculated at any point in a reaction not just during equilibrium

Shrayes Raman

The second part ratio represents K and K will be the same regardless of quantity

Shrayes Raman

Q is calculated the same exact way as K just it can be anytime during reaction not just during equilibrium

Shrayes Raman

Kc = Concentrions Kp = Partial Pressures. If given partial pressures use Kp and vice versa. This will tell you state of materials

Shrayes Raman

Le Chateliers principle is basically the idea that a chemical reaction will adjust to maintain chemical equilibrium. For instance if you remove product more product is produced to maintain the equilibrium

Shrayes Raman

I mean so far we have covered the ideal gas law/equation but we will probably learn more. PV=nRT

Shrayes Raman

When the pH is lower than pKa the H+ will associate with conjugate base again... if pH is higher than pKa then H+ will disassociate.

Shrayes Raman

Lavelle said that nonmetal oxides usually form acidic solutions

Shrayes Raman

There is a whole section in the Textbook dedicated to the helpful rules... You might find that helpful

Shrayes Raman

Molecules that have more than H+ tend to be polyprotic more often than not, especially when in the front of the name ie H2S04

Shrayes Raman

Weak bases and strong acids produce acidic solutions and vice versa

Shrayes Raman

Transition Metal cations form complexes that deprotanate some molecules leaving free H+ in the solution as H3O

Shrayes Raman

Understand the reasons behind its creation and the different molecules involved

Shrayes Raman

Donating a proton is a Bronsted Acid, Accepting a proton is a bronsted base.

Shrayes Raman

Delocalization of electrons lessens the instability caused by having one area of lone pair electrons spreading this out helps.

Shrayes Raman

Periodic trends say that the closer to fluorine an atom is the more electro negative.

Shrayes Raman

Draw the Lewis structure and see that the Cl form a ring around central carbon and then the lone pairs on the Cl pull on the Oxygen delocalizing the electrons which increases stability.

Shrayes Raman

Know the how to calculate the pH ie -log() and pOH and know how to interpret results

Shrayes Raman

The acid "donates" a H+ to to the surrounding H2O and forms H3O+. To get pH take negative log of the H+/H3O+ (They will be the same)

Shrayes Raman

Sp3 four regions of electron density

Shrayes Raman

Bond angle increases with more s character... Sp2 has more than Sp3 etc

Shrayes Raman

Sp3 has less s character than sp2 so so will have more than sp2... This means the bond angle will increase as a trend

Shrayes Raman

Be able to identify the bonds

Shrayes Raman

If a Lewis structure includes a double bond it will have a pi bond in the double bond

Shrayes Raman

Sigma bonds allow rotation as they have one axis of connection whereas pi bonds have two.

Shrayes Raman

They have much stronger repulsion that lone pair bonding or bonding orbitals thus they take up more space or rather push the other bonds away

Shrayes Raman

I think you should first draw most stable lewis structure and base vespr off that

Shrayes Raman

I think we need to know all of the ones that are listed in the notes and in the textbook in 2E

Shrayes Raman

Since the lewis dot structure show a lone pair on the Cl there will be a repulsion from the lone pair causing a 120 degree bent shape.

Shrayes Raman

Larger molecules i.e. Iodine will have a larger dipole moment

Shrayes Raman

Yes because the double bond does not allow rotation as it would break.

Shrayes Raman

Hybridization is not a bond necessarily, rather a model for how atomic orbitals of different energies fuse to form bonding orbitals

Shrayes Raman

Stronger bonds/interactions higher melting point

Shrayes Raman

They are the same as well as Van der Waals

Shrayes Raman

Hydrogen bonds occur due to the highly electro negative atoms interacting with hydrogens electrons

Shrayes Raman

NaCl has a ionic as opposed to a covalent bond which is stronger that HCl and there for melts at a higher temp

Shrayes Raman

H20 has rather strong hydrogen interactions that H2S does not

Shrayes Raman

All molecules possess london forces due to the nature of electron interations

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