CHEMISTRY COMMUNITY

Anita Wong 1H

https://www.facebook.com/photo.php?fbid ... ater&ifg=1

Anita Wong 1H

what i do is add the h2o to balance out the Os, then add H to balance H, then for the amount of H you add, add the same amount of OH to each side. The oh and h should combine to form h2o with can be added to/subtracted. just simplify from there!

Anita Wong 1H

its different at varying temperatures

Anita Wong 1H

theyre dependent on what youre given/what you want to find

Anita Wong 1H

so does that mean the amount of product and reactant is or isnt affected by adding a catalyst?

Anita Wong 1H

catalysts are in the reactant and intermediate is in the product side

Anita Wong 1H

yes! deltaU= 0 for isothermal reversible expansion

Anita Wong 1H

for monatomic gases!

Anita Wong 1H

Thank you Dr. Lavelle for being so kind and very interested in what you're teaching! it makes learning more engaging! I am glad to have had you as a professor for 2 quarters!

Anita Wong 1H

polyprotic acids contain more than one acidic proton. three acidic protons make it triprotic

Anita Wong 1H

you use it for irreverible reactions. usually youre given the external pressure pushing onto the system and you need to find the work of the systemm pushing out against the external pressure. and its w = -pdeltav

Anita Wong 1H

pka is in reference to ka whereas ph is in reference to H+

Anita Wong 1H

Henry Dudley 1G wrote:Can a bimolecular reaction be third order if one of the reactants is second order?

no i believe theyre directly related so thats not possible

Anita Wong 1H

Here’s another set!

Anita Wong 1H

Here are more pictures!

Anita Wong 1H

David Sarkissian 1K wrote:How do you post pictures? I have a decent one from up front, but I don’t know how to post it.

Refer to this: viewtopic.php?f=176&t=3916

Anita Wong 1H

when its negative its spontaneous. when its positive its not spontaneous.

Anita Wong 1H

material up to but not including nernst equation

Anita Wong 1H

MichaelMoreno2G wrote:Up to what section of electrochemistry do we need to study? I'm still a little confused so if someone can clarify that would be greatly appreciated.

up to but not including nernst

Anita Wong 1H

this is what i found: https://socratic.org/questions/why-is-l ... -oxidation
it had to do with what they thought in the early days of chemistry

Anita Wong 1H

I would ask your ta

Anita Wong 1H

they both go on the left side

Anita Wong 1H

gibbs free energy of formation is the change of Gibbs free energy that accompanies the formation of 1 mole of a substance in its standard state.

Anita Wong 1H

heres some examples: The simplest examples given in thermodynamics texts are the reversible and irreversible expansion of a gas. If you have a gas in a container connected to an evacuated container, and you open the stop-cock between them, the gas will expand without doing any work. This process is ...

Anita Wong 1H

In a irreversible reaction, the reactants react to form the products, which cannot revert back into reactants. In reversible reactions, as the reactants react with other reactants to form products, the products are reacting with other products to form reactants. Combustion cannot be undone. i am not...

Anita Wong 1H

i think thats all we need to know

Anita Wong 1H

open system: glass of tea evaporating
closed system: boba drink with the plastic seal
isolated system: calorimeter

Anita Wong 1H

no you shouldnt consider the heat of the surroundings in an isolated system

Anita Wong 1H

is is a given constant! should be in the equations sheet or in the problem

Anita Wong 1H

because a state property's value is determined by its current state and not dependent on the path taken to obtain that state

Anita Wong 1H

the stronger the bond, the more energy it requires to break it

Anita Wong 1H

strong acids dont have ka values. if you see a ka value, its most likely a weak acid

Anita Wong 1H

dont include solids and liquids. only include gases and aqueous solutions

Anita Wong 1H

its under Board index > Chem 14B > Administrative Questions and Class Announcements > Yekan Discussion slides (1B, 1H, 1J)

Anita Wong 1H

At equal concentrations, a strong acid will typically have a lower pH than a weak acid, since the strong one will donate more protons to the solution.

Anita Wong 1H

When comparing the two, usually you’ll be given K and you’ll have to calculate Q.

Anita Wong 1H

In lecture today, Professor Lavelle gave us the reaction N2(g) + 3H2(g) --> 2NH3(g) and described what would happen if we increased N2, increased NH3, and decreased H2. Can someone please explain to me each scenario, I am a bit confused still. If you increased N2, which is the reactant, a forward r...

Anita Wong 1H

Actually I found out that it’s most likely a TB error and the 7 N2 should have been a 5 N2

Anita Wong 1H

Jessica Chen 1F wrote:The equation definitely has to be balanced before you plug things in to solve K because the stoichiometric coefficients matter as the exponents.

does that mean the solution manual is wrong then?

Anita Wong 1H

I noticed that for 11.3 in the 6th edition that the equation isn't balanced. In the solutions manual, the answer is from the original/given equation. I thought we always had to balance equations... Are we supposed to leave the equation as it is when writing the equilibrium expression K? 11.3 Write t...

Anita Wong 1H

If you have a substance with nonpolar molecules , the only Intermolecular Forces of Attraction that exist are London-Dispersion forces, which are very weak. Therefore, a polar substance will have a stronger attraction between its molecules than a substance with nonpolar molecules.

Anita Wong 1H

To determine whether a substance is an acid or a base, count the hydrogens on each substance before and after the reaction. If the number of hydrogens has decreased that substance is the acid (donates hydrogen ions). If the number of hydrogens has increased that substance is the base (accepts hydrog...

Anita Wong 1H

the Bronsted definition: an acid is a proton (H+ ion) donor, and a base is a proton acceptor

the Lewis definition: an acid is an electron acceptor, and a base is an electron donor.

Anita Wong 1H

when the electronegativity difference is greater than 2.0, the bond is considered ionic.

Anita Wong 1H

Electrons in bonding orbitals stabilize the molecule because they are between the nuclei. Antibonding orbitals place less electron density between the nuclei. The nuclear repulsions are greater, so the energy of the molecule increases. Antibonding orbitals are at higher energy levels than bonding or...

Anita Wong 1H

I’d assume so

Anita Wong 1H

in a non-polar molecule, the whole molecule has zero dipole moment but bonds are polar. When two non-polar molecules comes closer to each other, the negative part (electrons) of one molecule attract the positive part (nucleus) of another molecule. As a result, two dipoles are induced.

Anita Wong 1H

yes i believe so

Anita Wong 1H

im not quite sure what your question is but i believe you are asking about the bond lengths of resonance and non resonance structures? what do you mean by in what context do we discuss them in?

Anita Wong 1H

our ta will hand it to us after lecture

Anita Wong 1H

chapter 3!

Anita Wong 1H

l= 0,1,2,3
orbitals: s,p,d,f

since l is i that means its in the p orbital which can hold up to 6 electrons (two on each __ __ __)

Anita Wong 1H

i know thar electron affinity and ionization energy are related. But i know that from lecture it was mentioned that elements towards the right have a lower ionization energy and elements towards the left have a higher ionization energy. When drawing the lewis dot structures, the element with the lea...

Anita Wong 1H

all energys on the energy levels are negative. its just a matter of becoming less negative when it moves down an energy level

Anita Wong 1H

you should know by the placement on the periodic table. just search it up and youll find images! when i went to the periodic trends review session the ta said we should know stuff like that

Anita Wong 1H

start off wherever you want. It completely up to you but try to make it balanced in a way i guess

Anita Wong 1H

they are both the same! they are just written differently! the h over 2 pi is call h bar and it yields the same result!

Anita Wong 1H

Light has both wave and photon/particle properties!

Anita Wong 1H

since lavelle will not be posting anymore modules, I heard the course reader helps alot!

Anita Wong 1H

yeah just chapter 1 and 2 for quantum world

Anita Wong 1H

I think during lecture he said we should just know the general order of the spectrum.

Anita Wong 1H

You would use v/c=3600 cm^-1 v=frequency and c=speed of light
from there just plug in the speed of light and solve for v which is the frequency

Anita Wong 1H

joonsoo explained it right! Because we are going from a higher energy level to a lower energy level, the change in energy is negative since we are going down energy levels.

Anita Wong 1H

I'm not entirely sure. But i assume it cannot be any other value other than what it already is since it is a 'constant'

Anita Wong 1H

I like my calculator because you can scroll and use the last answer to solve another problem! So if you calculate the molar mass of a compound you don't have to re type it! It's the Ti-30xs! I really recommend it!

Anita Wong 1H

I'd say just search up the formulas for the review. He will probably tell us later which ones to memorize if we ever need to. I wouldn't worry about memorizing for the test too if he specifically said we don't need to memorize them yet.

Anita Wong 1H

As per what the instructions on page F97 say: Since we are given the actual yield (25.2 g N2H4), we need to calculate the theoretical yield. 1) Start with the given mass of the reactant : 35.0 g NH3 2) Divide the mass by the molar mass of reactant NH3 to get the amount (mol) of reactant : 35.0 g NH3...

Anita Wong 1H

I'm guessing just maybe the date the assignment is due? Other than that I think what you posted is good!

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