CHEMISTRY COMMUNITY

lauraxie2e

How do you know which combination of solutions produces the greatest change in temperature?

lauraxie2e

The homework gives you a good idea of the questions but it is by no means indicative of the exam

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They do have an effect on reactions.

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Activation energy is not the same as change in enthalpy because change in enthalpy is the difference between products and reactants

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In word problems would they usually tell us the order so we would know what equation to use? If not, how would we determine what equation to use?

lauraxie2e

yes they give them to you but they aren't labelled so you have to br clear on which equations apply to which order

lauraxie2e

Is there a practice exam, if so where do I find it?

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what affects the rate constant?

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A catalyst is something that shows up in the reactants of the first equation but disappears by the products of the last equation as opposed to an intermediate which is produced throughout the reactions and disappears, right?

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How do you know if something is independent of the rate law?

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Aren't the answers supposed to be opposite of each other because one is rate of formation and one is rate of consumption?

lauraxie2e

it is always a whole number

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yes it is pretty easy though its just the derivative but also you could just find an average

lauraxie2e

use the comma only for the same phase, use the straight line for change in phase

lauraxie2e

it is more precise because it isn't an average

lauraxie2e

does anyone know where on the outline we need to know up to for the test?

lauraxie2e

the change in energy from the reactants to the products

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I think you have to email your TA and see.

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when the system does work on the surroundings

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it usually will tell you if it is irreversible or reversible

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it isn't necessarily 0 unless its isothermal and reversible

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negative is exothermic and positive is endothermic

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yes entropy is a state function

lauraxie2e

think about the reversibility of an equation

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Reversible is when a process can go either way and irreversible can only go one way. The entropy of the system of a reversible reaction is 0 and the the entropy of surroundings of a irreversible reaction is 0.

lauraxie2e

If temperature doesn't change, internal energy doesn't change.

lauraxie2e

when do we use -nrt vs p delta v

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half of thermodynamics

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its mostly to all free response

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p.282

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up to half of thermodynamics

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6-8pm

lauraxie2e

Work being done is to the surroundings and work being done on the system is to the system.

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Q is heat gained or lost and W is work done so combined they create the energy of the system

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Enthalpy is when pressure is held constant.

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Energy is lost due to entropy so we have to factor it in.

lauraxie2e

yes the phase change occurs after temperature change

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acid ionized over original x 100

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when they give you a concentration and ask for equilibrium concentration

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yes unless it states that it's a pure liquid

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can I still pick mine up or has it been shredded

lauraxie2e

delta s is enthalpy correct?

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you use the concentration of a base

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use the pH to calculate the concentration of H3O+ and then use the initial concentration to find the other values and set up the equation with products over reactants

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its inverse; lower pKa is a stronger acid

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when can I pick up my 14a final exam?

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I know when there is a small Ka in strong acids, you can disregard the change in the denominator when solving for the change to solve for pH, however does this also apply to weak acids?

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Kc is only at equilibrium, while Q is at any time of the reaction

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it is the gas constant and can either be seen as 8.314 J/mol·K or 0.082057 L⋅atm/mol⋅K

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Temperature is combined with the reactants to form the products so when you increase the temperature more reactants are formed changing K

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You use Kp

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We will most likely get a formula sheet that tells us the conversions.

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What is the cut off for the degrees Is for being able to act as a monodentate and bidentate ligand? For example in 9C5, I was told that CO3^2- is monodentate because the angle between the oxygens is only 120 degrees which is too small to bind to the same metal, but then it is also bidentate because ...

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No. Take the amphoteric oxides as an example (e.g. Al2O3). If you react Al2O3 with a strong acid, it will act as a base by producing hydroxide ions. If you react Al2O3 with a strong base, it will act as an acid by producing hydronium ions. None of the amphoteric oxides contain hydrogen. then can yo...

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Does a compound have to contain hydrogen to be amphoteric?

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I know H+ would be a Lewis acid, but would this be the same for H-?

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Are all polydentates chelating ligands because they have two or more points of attachment to the transition metal?

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What relevance is the litmus paper turning pink when the solution is tested on it, what does that show?

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I understand how you can identify Bronsted Acids and Bases when you are looking at a chemical equation, but how do you identify Bronsted Acids/Bases just by looking at the compound? For ex in J1, what is NH3

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If you're looking at a chemical equation, how do you know if it can be polydentate? For example HN(CH2CH2NH2)2?

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How do you know what Roman numeral to put after the name, when you're naming the compound? For example how do you know that [Fe(CN)6]4- is hexacyanidoferrate (II) and not hexacyanidoferrate (III)?

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It is mostly when the structure is symmetrical.

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It completely dissociates to lose one H

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it is anywhere where hydrogen can potentially bond to an element, so anywhere where there is F,O,N

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it is basically the same thing it is just if you view the compound as a proton acceptor/donor or electron acceptor/donor

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I don't believe double bonds effect hybridization because it is based on regions of electron density.

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Within the same period of anions with different charges, how do you determine which anion is most polarizable?

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How does dissociation energy relate to bond strength?

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does a molecule have to be polar to have dipole dipole IMFs

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What makes something have stronger London dispersion forces?

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Does anyone know why when we draw the lewis structure for this we draw the hydrogens next to each other and the chlorines next to each other instead of across from each other, because if we have them next to each other I understand why there is dipole dipole attraction forces, but if they were acros...

lauraxie2e

When do I use wedge and dash to draw models? For example CH4 in class we drew it using wedge and dash, but SF6 we didn't?

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On Lewis structures, do we have to know when do draw the wedge and dash for the midterm?

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As the forces get stronger the BP and MPs get higher.

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Butanol because when you look at the Lewis Structures, it has a hydrogen bond which holds the highest strength.

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I believe 3F or anything pass that

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CHI3 because the size of it makes the forces stronger

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Yes because usually molecules that weigh more have stronger forces so they will have higher MP/BP

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yes ideally you want every atom to have a formal charge of 0

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an acid accepts a lone pair and a base gives one up

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For 6D I am still unclear on what it means by wave like properties, could someone explain that to me?

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how come a) n=4 l=1 has six orbitals that could contain it?

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why is it that in Heisenbergs uncertainty principle (delta)p(delta)x is greater than h/4pi but also equal to h/2?

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It has multiple bonds that can be placed differently so the electrons flow around smoothly

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Formal charge is the charge assigned to a bonded atom. The formula is FC=V-(LP+0.5BP)

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Will bonding be on the midterm?

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When it says which metal is M^2+ and the configuration is [Ar]3d^7 do they leave off 4s^s because of the 2+ charge on the metal?

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What would be an example of an element that the d orbitals effect the number of valence electrons?

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say for instance n=3
would l=0,1,2 and ml=-1,0,1? would that be it?

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Because they have about the same mass, they should have pretty much the same wavelength

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the first one should be the equation for heisenburg's uncertainty principle

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Which elements were the exceptions to the normal electron configurations?

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so last week we did an example in class that said n=2; l=1; ml=-1

and the answer was that we had an electron that was in 2px state, I get the fact that it is 2p but why subscript x?

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radio, infrared, uv, visual light

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If the energy of light is less than the ionization energy does that mean no electrons are ejected?

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would the ionization energy be the same thing as work function?

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For tests will we have to know the electron mass?

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in the answers to questions using the uncertainty equation, do you leave it with the greater than equal to sign or just an equal sign?

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Sometimes they will give it to you, but it is pretty easy and helpful just to memorize them.

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I believe the answer is C because E=hv and so frequency and energy are directly related.

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