CHEMISTRY COMMUNITY

Callum Guo 1H

state functions are those that are not path-dependent. So the path it takes for it to get from it's intital to final state doesn't matter

Callum Guo 1H

we have until Wednesday

Callum Guo 1H

not sure if we are allowed to post answers online lol.

Callum Guo 1H

rate is determined by the slow step

Callum Guo 1H

Find out which one is the cathode and which one is the anode. And then plug it into the equation E= Ereduction - Eoxidation

Callum Guo 1H

Test grades are on myucla right now

Callum Guo 1H

You probably can't find exact problems that match up (otherwise there would be no point testing). Try looking at acid/base problems in like 6D

Callum Guo 1H

catalysts can be canceled out they just are necessary for the reaction to start in the first place and aren't created. Which is different than an intermediate because they are created through reactions and then canceled out.

Callum Guo 1H

Yeah if gives you the other variables I assume you can just solve for Ea

Callum Guo 1H

Delta G0 is at standard conditions while delta G can be at any

Callum Guo 1H

the question will usually tell you which ones match up

Callum Guo 1H

I think it's best to wait to see what Lavelle will say. He'll probably send an email.

Callum Guo 1H

Lavelle will probably send some sort of announcement. I assume he'll put it in the front office for us to pick up like our finals for 14A?

Callum Guo 1H

https://byjus.com/chemistry/zero-order-reaction/

Callum Guo 1H

add up the orders of all of the substances.

Callum Guo 1H

First balance all elements expect H and O. Balance O next using H2O and balance H with H+. Then you balance out charges by adding e-.

Callum Guo 1H

ln(K2/K1)= (-DeltaH/R)(1/T2 - 1/T1)

you can use it to calculate K value at a temperature given the K value at another temperature

Callum Guo 1H

Lavelle will probably send a email addressing it soon.

Callum Guo 1H

Lets just wait until he responds

Callum Guo 1H

Did you know that you can cool yourself to -273.15˚C and still be 0k?

Callum Guo 1H

What do you get when you mix sulfur, tungsten, and silver?
SWAG.

Callum Guo 1H

E is usually given in reduction reactions. If you have an oxidation reaction, you flip it.

Callum Guo 1H

Maintain electrical balance between the anode and cathode

Callum Guo 1H

reactions that are short are kinetically controlled while longer ones are thermo controlled

Callum Guo 1H

I think you just do practice problems in them

Callum Guo 1H

its the same as acidic solution expect you balance out the H+ with OH-

Callum Guo 1H

hg2 is a covalently bounded Mercury molecule while 2hg is 2 separate hg ions

Callum Guo 1H

probably a typo then if 3 people got the same answer

Callum Guo 1H

at ph 6 there is more products than reactants so it would be more negative

Callum Guo 1H

n is the mole of e-

Callum Guo 1H

I think the syllabus says he doesn't curve grades but he might adjust your grade at the end.

Callum Guo 1H

a reaction is spontaneous if gibbs free energy is negative

Callum Guo 1H

It is used to maintain a charge balance

Callum Guo 1H

Cp is constant pressure (5/2R) Cv is constant volume (3/2R)

Callum Guo 1H

I don't think it matters unless the question specifically asks for a unit

Callum Guo 1H

yes, gibbs free energy is a state function

Callum Guo 1H

for an isothermal process

Callum Guo 1H

when your system does work. so in this class, most of the time its when a gas expands.

Callum Guo 1H

You use it to find residual energy. Its useful if you have the number of particles and the amount of states it can be in

Callum Guo 1H

i think just assume constant pressure.

Callum Guo 1H

It takes energy to change a phase from one to another. For example, if you're heating Ice into liquid water, it'll take a certain amount of energy to get it from a solid to a liquid. This is the reason why steam at 100 degrees Celsius causes harsher burns than liquid water at 100 degrees Celsius (be...

Callum Guo 1H

i think all the equations are given to us? You will have "memorize"/understand some conceptual things because not everything is calculations

Callum Guo 1H

no slides : (

Callum Guo 1H

It takes energy to change phases. (heat of vaporization, heat of fusion)

Callum Guo 1H

yeah, the second law says that entropy of the universe is increasing

Callum Guo 1H

You have to account for energy it takes for changes in phases and the difference in specific heat for different phases.

Callum Guo 1H

Constant external pressure

Callum Guo 1H

There is a chart of gas constants. Match up R with the correct units.

Callum Guo 1H

Internal energy remains constant throughout the reaction (first law of thermo) so it doesn't matter how you get from the initial to final values.

Callum Guo 1H

Positive because you add energy

Callum Guo 1H

It's conservation of energy: energy is can't be created or destroyed. So the total energy of a internal system remains constant.

Callum Guo 1H

maybe https://www.khanacademy.org/science/bio ... to-entropy

Callum Guo 1H

Trying doing the opposite of what you did (i.e. since its -b plus or minus ... , try minus if you did plus and plus if you did minus)

Callum Guo 1H

Pressure shifts the reaction to the side with the least moles of gas if you add gas and the opposite if you remove gas

Temperature depends on whether or not the reaction is endothermic or exothermic

Callum Guo 1H

You would probably take the 10^-pka to convert it into Ka and then make a ICE table to find the concentration of H+ ions. After that, you would take the -log of the H+ concentration.

Callum Guo 1H

It takes energy to convert liquid into a gas. During this period of time, more energy is added to the substance (water) without changing the temperture. Thus, you can have a liquid and a gas at the same temperature but the gas would have much more energy

Callum Guo 1H

Make an ICE table and solve for H+ concentration. Find the pH by taking the -log of it, and then subtract that value from 14 to find poh

Callum Guo 1H

It takes energy for any substance to move from liquid to gas state. During this period in which bonds are being broken, energy added to the substances does not increase the temperature. Therefore, you could have steam that is 100 degrees with more energy compared to 100 degree water.

Callum Guo 1H

Usually, you would look at Ka value and set up an ICE table; however, since sulfuric acid is an strong acid, the reaction goes to completion and you can just find the concentration of [H+] via stoich and then take the -log of it.

Callum Guo 1H

the path a reaction takes does not change the enthalpy of the reaction

Callum Guo 1H

It's during your discussion this week

Callum Guo 1H

On Friday, we didn't really learn new material. We just did application of what we learned and some problems

Callum Guo 1H

The value of x changes 0.1 so little that it's negligible

Callum Guo 1H

You usually use ICE tables to find the concentration of a reactant or product given that the reaction does not go to completion (at equilibrium there are both reactants and products still being formed).

Callum Guo 1H

The easiest way to think about it is if you have 2 moles of gas on onside and 1 mole of gas on the other. If you increase the pressure, the reaction will favor the side with 1 mole of gas.

Callum Guo 1H

to calculate pOH. You find the concentration of OH- molecules and then take the -log[OH-] to find the pOH

Callum Guo 1H

Lower pKa means a stronger acid

Callum Guo 1H

viewtopic.php?t=24493

Callum Guo 1H

There some stuff on page 442 of the textbook. You should just go through the chapters and find these sections

Callum Guo 1H

We'll probably go over what we will have to know on the test this week.

Callum Guo 1H

Endothermic reactions favor product formation if the temperature increases and vice versa. Exothermic reactions favor reactant formation if temperture increase. The opposite is true if temperture decreases. Equations tend to resist change by doing the opposite of what is happening around them

Callum Guo 1H

Temperature is how you decide between the three. There should be a colmum that shows temperature for and a given K for that

Callum Guo 1H

it's week 3 during your discussion i think

Callum Guo 1H

it's proton transfer between two of the same atom. one of them acts as a bronsted acid and the other as a bronsted base.

Callum Guo 1H

Yeah its only used for gases. Every gas has a partial pressure and when all the partial pressures get added together, you get the total pressure of the system.

Callum Guo 1H

Yes, solving for Q is the same way you would solve for K

Callum Guo 1H

You can change the equation around so that you can find the pressure of elements which helps you find the equilibrium for gases

Callum Guo 1H

It depends if the pressure given is in atm or pascals

Callum Guo 1H

Yes, the ideal gas law only applies to gases

Callum Guo 1H

Yeah you only count things that are in aqeuous states and gas states if you are calculated the equilibrium for pressure

Callum Guo 1H

Decide whether an aqueous solution of each of the following salts has a pH equal to, greater than, or less than 7. Write a chemical equation to justify your answer: AlCl3 The Cl doesn't factor into pH since it came from a strong acid. So you use the Al which would be Al3+ as an ion. But the solution...

Callum Guo 1H

no i dont think.

Callum Guo 1H

I think F only forms only single bonds because of its electronegativity

Callum Guo 1H

it's -log[h+] and i doubt we would need to derive it

Callum Guo 1H

How do you know if an element's name originates from a Latin name like Fe(ferrum)

Callum Guo 1H

naming for what?

Callum Guo 1H

This may help. https://m.youtube.com/watch?v=yjulD5dMjn8

Callum Guo 1H

Probably go over your midterm, go over homework problems, and examples Lavelle emphasized in class.

Callum Guo 1H

I’m not sure, would like to know to lol

Callum Guo 1H

I think it would be helpful to know them

Callum Guo 1H

pH=-log[h+]

Callum Guo 1H

I think so, unless he gives us another one

Callum Guo 1H

probably like the midterm, mostly calculation with some conceptual problems.

Callum Guo 1H

compare ka values

Callum Guo 1H

yes it could go below negative. The way you calculate ph is -log[h+]

Callum Guo 1H

HCL is a strong acid

Callum Guo 1H

What's Ba(Na2)?

a banana.

Callum Guo 1H

What weapon can you make from the elements potassium, nickel and iron? A KNiFe.

Callum Guo 1H

no hybridization was not on the test

Callum Guo 1H

i dont think so

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