CHEMISTRY COMMUNITY

Cristina Subratie 1C

I do not think so I think just knowing the notation of the cell diagram should be sufficient since the textbook questions are generally representative and we were not asked to do that

Cristina Subratie 1C

so here we are essentially finding the equilibrium constant for the conjugate base of the acid in the equation provided. you can solve for Ka and then use the formula provided in the previous reply in order to solve for Kb since we know Kw and Ka.

Cristina Subratie 1C

I think knowing how to manipulate the equations and apply them is what's important since the main equations are given.

Cristina Subratie 1C

the derivative of this equation would look like this: -RTlnK = -H - Ts lnK= (H/-RT) - (Ts/-RT) lnK = (H/-RT) + (q/RT) lnK = (H/-RT) + (H/RT) lnK = -H/R (1/T - 1/T) lnK2 - lnK1 = -H/R (1/T2 - 1/T1) ln(K2/K1) = -H/R (1/T2 - 1/T1) Van't Hoff equation * H is the change in H and s is the change in s - I ...

Cristina Subratie 1C

Why is the cell diagram here have Ag(s) as both the anode and cathode. If the reaction is AgBr -> Ag+ + Br- and Ag is being reduced at the cathode and Br- is reduced at the anode- why is Ag(s) the electrode for both the anode and cathode. Why isn't Br(s) the anode? Also where would the entire solid ...

Cristina Subratie 1C

how do we know here that we should be calculating work as well as the enthalpy? how do we infer work is being done from the information given?

Cristina Subratie 1C

why aren't all exothermic reactions spontaneous if they do not require energy? is there a real life example of an exothermic reaction that is not spontaneous

Cristina Subratie 1C

why is no work done under free expansion?

Cristina Subratie 1C

I was wondering if the reasoning for question 10 was that because as the temperature increases the equilibrium constant increases showing that there is favoring of products as the temperature increases which would mean that heat is being used up to counter the increase in temperature and endothermic...

Cristina Subratie 1C

sorry I mean the anode since it has to be oxidized instead of reduced

Cristina Subratie 1C

suppose you are given a question where hydrogen is one electrode and and other electrode is another solid metal with an aqueous solution surrounding it. How would you decipher which one is the cathode or anode? Would it be because we should know the reduction potential of H2 is 0 and therefore would...

Cristina Subratie 1C

what would the oxidation numbers be for each in this equation:
H2O2 -> 2H2O + O2 ?

Cristina Subratie 1C

when sodium fluoride dissociates in water why do we get HF and OH- instead of NaOH?

Cristina Subratie 1C

can someone explain how we are able to add H2O on both sides for this. I thought the rules were as follows for basic conditions for oxidation: identify species being oxidized write oxidation skeletal half reaction balance O by adding H2O on the left balance H+ by adding OH- on the same side of H2O c...

Cristina Subratie 1C

is anyone able to pinpoint what I am doing wrong here...I keep getting the incorrect answer: this is my working out: kcat/kuncat = (e^(-Ea/RT))/(e^(-Ea/RT)) convert Ea to joules per mole = (e^(-70000/8.314*295))/(e^(-133000/8.314*295)) = (e^(-70000/2452.63))/(e^(-133000/2452.63)) = (e^(-28.54))/(e^(...

Cristina Subratie 1C

partial pressures are associated with gas and concentration with other phases meaning that they are essentially giving the same answer- do not worry about the units of Q

Cristina Subratie 1C

when the standard potential is positive the reaction is spontaneous meaning that the products are favored. This means that the equilibrium constant is larger and often greater than 1 to show that a lot of the reactants are dissociating.

Cristina Subratie 1C

why is tin assumed to be the electrode of the anode? How is this inferred from the question? what happens to the NO3- in the half equation?

Cristina Subratie 1C

not understanding how C2H5OH -> C2H4O + 2H+ + 2e-
Where is the water in the equation, why don't we include it and wouldn't the 2H+ and 2e- cancel each other out and the charges still would not be balanced?

Cristina Subratie 1C

can someone explain the steps to how we knew how to balance both the half equations for number 1.

Cristina Subratie 1C

in the equation Zn + BrO3- -> Zn2+ + Br-1
the balanced eqn is 3Zn + BrO3- + 3H+ -> 3Zn2+ + Br-1 + 3H2O
how do we know to use hydrogen here and how do we know this is under acidic conditions

Cristina Subratie 1C

can someone explain how from lecture on Monday when describing the concentration the E was described as having typically low voltage...why is this important?

Cristina Subratie 1C

when the cell reaches equilibrium we know the change in G cell is 0 and Q=K. therefore E standard =( RT/nF) (lnK)

Cristina Subratie 1C

also to note for the standard E cell the equation will be E standard= (0.0592/n)logK

Cristina Subratie 1C

thank you I figured it out

Cristina Subratie 1C

still not seeing what I am doing wrong here?

Cristina Subratie 1C

I can't figure out what I am doing wrong here but I keep getting this wrong on achieve. This is my working out:
E= E - (RT/zF)lnQ
E= 1.94 - [(8.3145)(298.15)/(2)(96485)] ln(0.79/0.013)
E= 1.94- 0.12846(4.107)
E= 1.41

Cristina Subratie 1C

the anode is always negative charge and losing electrons which oxidizes while the cathode always positive and allows for gain of electrons /reduction - electrons flow from anode to cathode

Cristina Subratie 1C

platinum is only separated by one line because electrons can flow through it

Cristina Subratie 1C

can someone clarify the significance of the salt bridge?

Cristina Subratie 1C

Can someone clarify the use of the salt bridge?

Cristina Subratie 1C

Thank you so much for this advice! It is really helpful to hear about other people's journeys.

Cristina Subratie 1C

My acronym to remember oxidation and reduction is OILRIG
Oxidation
Is
Loss
Reduction
Is
Gain

Cristina Subratie 1C

Hi for question 4.9 part c why must the reaction be cooled to maintain a constant T? If the reaction is exothermic doesn't that mean the temperature of the surroundings is increasing and therefore the temperature of the reaction is decreasing since it is releasing heat. Wouldn't that suggest that yo...

Cristina Subratie 1C

why does it matter which one the limiting reagent is

Cristina Subratie 1C

determine which of the following. compounds are stable with respect to decomposition into their elements under standard conditions at 25C. PCl5 which has a free energy of formation of -305kJ/mol which because is less than 0 means the forward reaction is spontaneous and the products are more stable t...

Cristina Subratie 1C

why is it that when a reversible process occurs the total entropy would be 0

Cristina Subratie 1C

can someone explain the reasoning behind this question specifically the part about resonance and how it affects the body enthalpy benzene is more stable and less reactive than would be predicted from its Kekule structures. Use the data to calculate the lowering in molar energy when resonance is allo...

Cristina Subratie 1C

in lecture there was an equation mentioned qp = gCsp(change in T)
I was wondering what the Csp stood for?

Cristina Subratie 1C

is the change in H the same thing as q?

Cristina Subratie 1C

usually irreversible reactions are faster and are usually biological

Cristina Subratie 1C

temperature always held constant but volume changing and pressure changing which is why the equation turns out to be what was said in previous response

Cristina Subratie 1C

Cl2 is the most thermodynamically stable because it is in its lowest state of energy

Cristina Subratie 1C

I believe its because the PCl5 is what is being initially placed for the reaction.

Cristina Subratie 1C

under what conditions do we ignore the second deprotonation of the acid

Cristina Subratie 1C

For number 7 I am using the equation:

H+ + ClO- + Na+ + ClO- + H2O -> HClO- + OH- + Na+

I am wondering what happened to the H+ and why my equation might be wrong

Cristina Subratie 1C

the seasaw concept is just showing us that with a stronger acid there is a weaker conjugate base and with a stronger base there is a weaker conjugate acid

Cristina Subratie 1C

can someone explain what was said about solving the cubic equation in the lecture, im not fully understanding. I know that I should not solve the entire thing via factorization and there is an approximation/trick I can use

Cristina Subratie 1C

Yes this is still happening however since they only give a small amount to the solution they are neglected from the equation

Cristina Subratie 1C

is the conjugate base or acid essentially the same as the salt being formed?

Cristina Subratie 1C

partial pressure generally applies to gaseous state

Cristina Subratie 1C

this is because they are present in excess and there change is insignificant

Cristina Subratie 1C

how do we know when the partial pressure is 0

Cristina Subratie 1C

We are able to calculate the initial concentration of SO3 and then when calculating the equilibrium concentration...why is it that we must subtract the initial from the conc of the SO2? Why are subtracting from SO2 and why are we not also subtracting the O2?

Search found 54 matches