CHEMISTRY COMMUNITY

Abigail Tran 14a

anodes more readily reacts to form cations that cathodes

Abigail Tran 14a

the only way out is through!!! push through!!!

Abigail Tran 14a

what are some last minute details that are important but easy overlooked when studying for the chem final? for example, something i easily forget but is important is that rates of forward and reverse reactions are equal

Abigail Tran 14a

the equation for rate law is r=k[A]^x[B]^y

Abigail Tran 14a

When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules. One chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere. Chlorofluorocarbons (CFCs) and other halogenated ozone-depleting substances (ODS) are...

Abigail Tran 14a

When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules. One chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere.

Abigail Tran 14a

what are the basic and most important rules of le chateliers principle

Abigail Tran 14a

ideal gas is hypothetical gas that follows certain set of rules such as they dont repel or attract eachother

Abigail Tran 14a

negative delta g is spontaneous, positive delta g is nonspontaneous, delta g=0 mean rxn is at equilibrium

Abigail Tran 14a

ph is how we measure how basic or acidic a solution is. it can be calculated by ph=-log10[h3o+]

Abigail Tran 14a

Hess law is the law of summation of heat
rules include
if u multiply rxn by a number, multiply change in heat by that number
when u do the reverse reaction, flip the sign of change in heat

Abigail Tran 14a

how come when reaction constant is positive, cell potential is positive and when reaction constant is negative, cell potential is negative. and the opposite for gibbs free energy

Abigail Tran 14a

how come when reaction constant is positive, cell potential is positive and when reaction constant is negative, cell potential is negative. and the opposite for gibbs free energy

Abigail Tran 14a

rate= k[A]^a[B]^b where k is the rate constant, A is the concentration, a is the order of reaction in respect to A

Abigail Tran 14a

The activation energy can be calculated by taking the difference of the transition state enthalpy and the reactant enthalpy

Abigail Tran 14a

in ΔG∘=−nFE∘cell what does the F stand for and why?

Abigail Tran 14a

in ΔG∘=−nFE∘cell what does the F stand for and why?

Abigail Tran 14a

how do you know whether a reaction is spontaneous or not based on standard reduction potential

Abigail Tran 14a

what makes a good oxidizing agent and what makes a poor one?

Abigail Tran 14a

Complete the half‑reactions for the cell shown, and show the shorthand notation for the cell. The electrode on the left is the anode, and the one on the right is the cathode. the anode half rxn is Pb + 2Cl- --> PbCl2 + 2e- the cathode half rxn is 2AgCl + 2e- --> 2Ag + 2Cl but why isnt it 2Ag + 2Cl -...

Abigail Tran 14a

Identify the oxidizing and reducing agents in the skeletal (unbalanced) reaction. Then, balance the reaction, including the phase (solid, liquid, etc.) of each species. The reaction takes place in basic aqueous solution. Cl2O7(g)+H2O2(aq)⟶ClO−2(aq)+O2(g) I was wondering once you balance oxygen for h...

Abigail Tran 14a

i been listening to super stars by yves tumor its a super good song

Abigail Tran 14a

first I determined the oxidation numbers of each element in each half‑reaction. i balanced the atoms of each half reaction, balancing every element except hydrogen and oxygen first . then i used h2o to balance the oxygen atoms. for basic solutions, i used oh to balance hydrogen and then h2o again to...

Abigail Tran 14a

when q<k the amount of products at the time is greater than the amount of products at equilibrium so the reaction will shift left towards reactants to reach equillibrium

Abigail Tran 14a

Kw is the equilibrium constant for water

Abigail Tran 14a

heat capacity is an extensive property because it depends on the amount of matter

Abigail Tran 14a

a closed system is where matter can be exchanged but energy cannot, an isolated system is where neither matter nor energy can be exchanged

Abigail Tran 14a

a closed system is where matter can be exchanged but energy cannot, an isolated system is where neither matter nor energy can be exchanged

Abigail Tran 14a

exothermic is when heat EXits and endothermic is when heat ENters

Abigail Tran 14a

when delta h is negative that means it is losing heat and when delta h is positive it means gaining heat

Abigail Tran 14a

i did heat required to melt ice + heat required to bring ice to final temp= heat required to bring water to final temp

Abigail Tran 14a

in an open system, the system can exchange matter and energy with its surroundings.

Abigail Tran 14a

in an open system, the system can exchange matter and energy with its surroundings.

Abigail Tran 14a

favoring a product means the reaction will go towards the product meaning it will form more of the product. if a reaction favors a reactant, the reaction will go towards the reactant

Abigail Tran 14a

the answer is [HA]=/=[H3O+]

Abigail Tran 14a

i think they are interchangeable since the units are so similar but i think atm is more commonly used.

Abigail Tran 14a

ice charts are usually used to find concentration so mol/L or M is usually preferred.

Abigail Tran 14a

in a closed system, heat can be exchanged but not matter. in an isolated system, neither heat nor matter can be exchanged.

Abigail Tran 14a

I really thought it was as long as you have 50 by the end of the quarter.

Abigail Tran 14a

when a reaction is exothermic, heat is being released or lost so the enthalpy is negative and when a reaction is endothermic, heat is going in/gained so enthalpy is positive

Abigail Tran 14a

i love the ice box method its so satisfying to see how everything fits together :)

Abigail Tran 14a

R = 0.0821 liter·atm/mol·K
R = 8.3145 J/mol·K
R = 8.2057 m3·atm/mol·K
R = 62.3637 L·Torr/mol·K or L·mmHg/mol·K
usually for ov=nrt, we would use .0821, but for w = -nRTln(V2/V1), we would use 8.3145

Abigail Tran 14a

Yes, there is a difference because when you use Ka, -logx will give you pH, but when you use Kb, -logx will give you pOH and pH and pOH will add up tog get 14. ka x Kb= 1x 10^-14

Abigail Tran 14a

You use Hess's law to find total bond enthalpies, enthalpies of reactions or products, and to calculate heat of formation, combustion neutralizations, ionization, etc...It is basically like adding all of the enthalpies in order to find total enthalpy. If you multiply an equation by n, you have to ra...

Abigail Tran 14a

Yes gases are included but aqueous solutions are included as well.

Abigail Tran 14a

specific heat capacity is an intensive property as it does not depend on quantity. the heat capacity per gram is the same

Abigail Tran 14a

I was wondering the same thing and couldn't find it either.

Abigail Tran 14a

kp can be atm or barr because they are very similar

Abigail Tran 14a

find concentration of acid then divide it by the concentration given in the question and multiply by 100 to get perventage

Abigail Tran 14a

when q is greater than there is more products and it needs to be balanced out by creating more reactants and shifting the reaction to shift to the left

Abigail Tran 14a

find concentration of amine and divide it by initial concentration and multiply by 100 to get percentage

Abigail Tran 14a

K is the equillibrium constant and Q is the reaction constant. When q>k reaction favors reactants causing system to shift left.

Abigail Tran 14a

R is a constant so it does not change.

Abigail Tran 14a

R is a constant so it does not change.

Abigail Tran 14a

You use an ICE table when you are given equilibrium reaction constant and initial concentrations. Something I like to look out for when to use ICE tables is when the problem says ""determine molar concentrations in the mixture at equilibrium,"

Abigail Tran 14a

adding a catalyst will not affect value of k, but changing the temperature will

Abigail Tran 14a

adding a catalyst will not affect value of k, but changing the temperature will

Abigail Tran 14a

In the original equation 2N2+O2-->2N2O, the concentration of N2O at equilibrium is 2x since there are 2mols of N2O at equilibrium. So once we solve for x which is 3.3x10-21 mols, we multiply it be 2 to get 6.6x10^-21.

Abigail Tran 14a

When Q>K, the reaction quotient is greater than the equilibrium quotient which means the concentration of products is greater than the concentration of reactants so the reaction will have to go in reverse.

Abigail Tran 14a

see saw because it has 5 connections and 1 is a lone pair

Abigail Tran 14a

We dont have to worry ao=bout sigfigs because they are multiple choice and generally the options have the same #sigifigs

Abigail Tran 14a

pH and pOH are related because they add up to 14

Abigail Tran 14a

pH and pOH are related because they add up to 14

Abigail Tran 14a

for a weak acid, when pka<OH --> the acid is charged, when pka>OH --> the acid is neutral

Abigail Tran 14a

It is indicating 25 degrees because that is the temperature condition that allows the equations to work

Abigail Tran 14a

It is indicating 25 degrees because that is the temperature condition that allows the equations to work

Abigail Tran 14a

pka is a number that shows how strong or weak an acid is.

Abigail Tran 14a

here are some important pH equations
pH = -log[H+]
pOH = -log[OH-]
1.0 x 10^14 = [H+][OH-]
14.00 = pH + pOH

Abigail Tran 14a

All ligands are Lewis bases but not all Lewis bases are ligands. Ligands are species that bond to metal ions using an electron pair since they have that electron pair available to donate by definition they are lewis bases.

Abigail Tran 14a

All ligands are Lewis bases but not all Lewis bases are ligands. Ligands are species that bond to metal ions using an electron pair since they have that electron pair available to donate by definition they are lewis bases.

Abigail Tran 14a

Yes you can find pOH from pH. All you have to do is subtract pH from 14 because pH+pOH=14

Abigail Tran 14a

between RbOH and Sr(OH)2, Sr(OH)2 is the stronger base since it has 2 "OH"'s.

Abigail Tran 14a

seesaw has 5: 4 bonds and 1 lone pair.

Abigail Tran 14a

strong acids: H2SO4 (or sulfuric acid), HI (hydrologic acid), HBr (hydrobromic acid), HNO3 (nitric acid), HCl (hydrochloric acid) and HClO4 (perchloric acid)
You can use the acronym So I Brought No Clean Clothes to memorize this.

Abigail Tran 14a

h2o has two bonds and one lone pair so it is bent

Abigail Tran 14a

The different polarities of the C-H and C-Cl bonds mean the effect of the polar bonds are not cancelled so the molecule is polar.

Abigail Tran 14a

yes, cations are usually metals and are positively charged!

Abigail Tran 14a

acid rain occurs when Nitrogen dioxide, Sulfur dioxide, or carbon dioxide reacts with water in the air so we can prevent acid rain by reducing pollutants in the air and carbon emissions.

Abigail Tran 14a

Kw is the equilibrium constant, the dissociation/ionization constant of water. In pure water [H+] = [OH-] = 1.00x10-7 M.

Abigail Tran 14a

yes they are interchangable!

Abigail Tran 14a

Polar models are assymetrical while nonpolar are symetrical

Abigail Tran 14a

XeF4 is a common molecule with a square planar geometry

Abigail Tran 14a

Lewis acids and bases accept or donate electron pairs. Bronsted Lowry acids and bases accept or donate hydrogen ions ( H+ )

Abigail Tran 14a

Hi! I am so glad that midterm 2 was successful for you! I will definitely be using the studying methods you mentioned. I especially found the tip to complete homework problems as we learn about them in lecture to be helpful! Good luck on the rest of the quarter!

Abigail Tran 14a

Hi midterm results have already come out! I think they came out Saturday night and you can check them on myucla. Also I am thankful to be at ucla with all of these bright and caring people!! Have a great thanksgiving

Abigail Tran 14a

I am not sure but here is a helpful chart that you could use to study! https://www.google.com/url?sa=i&url=https%3A%2F%2Flearnwithdrscott.com%2Fpolyatomic-ions-list-and-worksheet%2F&psig=AOvVaw0YNYE0coaX1z5RkS2efWSv&ust=1636444918262000&source=images&cd=vfe&ved=0CAsQjRxqFwoTC...

Abigail Tran 14a

intra means within so intramolecular is within a molecule. inter means between intermolecular is between molecules

Abigail Tran 14a

intra means within so intramolecular is within a molecule. inter means between intermolecular is between molecules

Abigail Tran 14a

ldf--> dipole dipole --> hbond--> ion ion

Abigail Tran 14a

I believe strongest to weakest is i2, br2, cl2, because ldfs are stronger between larger atoms.

Abigail Tran 14a

Intra means within so intramolecular means within a molecule. Inter means in between so intermolecular means in between molecules.

Abigail Tran 14a

Those elements are very electronegative so they are hydrogen bond acceptors. They withdraw the majority of the electron density in the covalent bond with hydrogen, leaving the h atom very electron deficient.

Abigail Tran 14a

I hope this chart is helpful! https://www.google.com/url?sa=i&url=htt ... AdAAAAABAI

Abigail Tran 14a

You can determine strength of london dispersion forces through molecular size: larger and heavier atoms have stronger dispersion forces than smaller and lighter ones. London dispersion forces tend to be stronger between molecules that are easily polarized and weaker between molecules that are not ea...

Abigail Tran 14a

During my discussion, the TA said that we can go over the problems we got wrong in the midterm during TA office hours:)

Abigail Tran 14a

electron affinity increases up and across the periodic table. Hope that helps!

Abigail Tran 14a

There is no way to see your participation credit as far as I know, but you can see how many posts you have made on chemistry community and divide it by the week number and if the result is 5, then you have met the participation credit so far!

Abigail Tran 14a

One way to remember sigfigs is that everything after the decimal is counted as a significant figure. Also, any zeroes between other numbers is counted as a sigfig

Abigail Tran 14a

Dipole moments tell us where the electrons on a molecule are, they can also tell us the shape of molecules. They are important for many properties such as ability to dissolve solutes, melting and boiling points, and reactivity in general.

Abigail Tran 14a

Double bonds are shorter because they are stronger so they bring atoms closer together so that the distance between them is shorter and therefore the bond is shorter

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