CHEMISTRY COMMUNITY

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most likely for the test we will be given that information, not required to look it up from a chart ourselves.

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Extensive: mass dependent
intensive: mass independent
Determines what units or constants you use in equation

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When E is positive it is spontaneous, so delta G needs to be negative

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When Q and Kc are equal then the reaction has reached equilibrium and Q will stay the same. This doesn't mean that the reaction is no longer occurring rather that both the forward reaction and the reverse reaction are happening at the same rate

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Q will tend to go towards Kc, so when Q >Kc it will shift towards the reactants and when Q<Kc it will shift towards the products.

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Ssys + Ssurr = Stot
same thing applies when you make them all delta

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concentration of reactants does not affect rate.

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Most heterogeneous catalysts are solids, and in order to maximize catalyst-substrate interaction it needs to be porous or finely divided.

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The linear form is useful for graphical analysis and basic comprehension. It can also be useful for finding k, because its the slope of the line. Either work for simple calculation using the relationship between time and concentration of the reactant.

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It will be given, but you might have to do some Ka pKa manipulation to find out, so make sure you remember how

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With the reaction mechanisms method we can make educated guesses on reaction rates for untried reactions with the same or similar steps.

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A reaction mechanism is the combination of all the elementary reactions that overall chemical change goes through.

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activation energy is always accounted for in both endo and exothermic reactions, but that doesn't determine net loss/gain of energy

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write out the skeletal reaction like H+ ---> H20. and OH- ---> H2O and then follow the regular instructions for balancing a redox reaction.

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Either Joules or Kilojoules per mole depending on the context of the problem

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If the reactant is included both in the initial reactants and the products of the final step then it is a catalyst, because it is used in the reaction but is reformed by the end

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Transition state theory deals with all reactions, while collision theory applies only to reactions in the gas phase because all other phases are colliding much more frequently.

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The frequency factor represents frequency of collisions between reactant molecules

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If the observed rate law is given then you dont need to worry about identifying the slow step because it will just be the one that matches the given observed rate law

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You would need to run the experiment, and then check with the pre equilibrium method to confirm. In the test the slow step will most likely be given.

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The rate constant is proportional to the reaction rate so if rate constant doubles so does the reaction rate.

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You use the Arrhenius equation when you need to determine the effect of a temp change on the rate constant, which changes the overall reaction rate.

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The pre equilibrium approach assumes that the reactants and intermediates are in equilibrium, namely the rate limiting step is at equilibrium because it is backed up at that point.

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Lavelles website has the link to the equations and constants sheet that we have been using, so it seems it will suffice for the content we are being tested on. The rest of the other stuff we would need like enthalpy of formation values would no question be available to us in some way.

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Usually the slow step will be given, but you might be given data about the different steps and have to analyze it to determine the rate determining step

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More specifically the Arrhenius equation can show us the impact of temperature, a catalyst, energy barrier, and frequency and orientation of collisions, which are all not shown in the rate law.

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Activated complex refers to a range of configurations near the transition state that the atoms pass through in the transformation from products, while the transition state refers to only the highest potential energy configuration of the atoms during the reaction.

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The difference between balancing in an acidic or a basic solution is when you are balancing H. If you have an acidic solution you just add H+ to the side that needs H+. But with a basic solution you need to add H2O to the side that needs the H+ and OH- to the other side, so that the net difference i...

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From their oxidation numbers determine the species being oxidized and reduced and then from their unbalanced equations balance the half reactions, then have the electrons in both equations cancel by multiplying both equations to make them cancel, then you can combine the equations, cancel stuff out,...

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If the rate of the reaction is proportional to the concentration of the reactants then it is an elementary reaction

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Molecular shape and structure for sure Ellis! Maybe ochem will suite me better who knows

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The Law of Conservation of Energy was coined by Mayer in 1842, and now it has been compiled with the others as the 1st law of Thermodynamics. They are one and the same

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Yes because endothermic reactions require energy for the reaction to go forward, so endothermic reactions are held back by the lack of energy, but when you supply that energy in the form of heat with higher temperatures the reaction is allowed to take place more often resulting in a equilibrium shif...

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delta U can be 0 when a system is doing work as a reversible expansion and when the energy lost is replaced by heat flow into the system (isothermic).

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We can definitely use that equation, cause its just a reworked 1st law equation. Under constant pressure q=delta H and w= -P deltaV

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Anyone know a good mnemonic device for all the state variables we need to know?

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U is internal energy, meaning the energy inside of a system at a time. Is also a state function. Usually used in terms of change of internal energy, delta U

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Because heat and work are related to delta U directly as the two different methods showing how energy is transferred in and out of the system. Say delta U was +2kJ, the q and w could be any combination of energy values as long as the sum is +2kJ.

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U is a state property representing internal energy of a system. So in equations it represents the change in internal energy from initial and final states.

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This is assuming it is an open or closed system with a piston, where heat and compression/expansion change, but in an isolated system the delta U is just q + w =0 because the point of an isolated system is that the internal energy doesn't change

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if delta P is 0 (under constant pressure) then delta U = delta H - P deltaV

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If delta V is 0 (constant volume) then its just deltaU = q

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In a closed system with no constants its just delta U = q +w

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if delta P is 0 (under constant pressure) then delta U = delta H - P deltaV

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If delta Volume is 0 then delta U = work

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heat capacity is the energy required to raise temp of a substance which is much different from the energy change from forming a bond. These are separate ideas as one deals with change in temp and phase of a substance and the other is chemical changes to the substance

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Its basically there to save us time so we dont have to use the quadratic formula, plus we can assume the change to the concentration to the reactant is nonexistent which is nice as well. You can always just do the problems with the quadratic formula and it will still be correct if you ever forget th...

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for example, when K>Q, then the reaction shifts to the right

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Its important to differentiate between the different K subscripts because they aren't all the same, Kw is a constant while Kc Ka Kb Kp all mean different things

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for example, when Kc>Q, then the reaction shifts to the right

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For aqueous solutions you need to calculate the Q of the solution currently and compare it to the Kc and then you can tell which way it is going.

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shifted implies that the reaction was already at equilibrium and something changed it, and lies to the right/left just means that it is product/reactant favored

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Kw is really nifty because if you have one of [OH-] or [H30+] you can find the other because you know Kw is 10^-14. Ba(OH)2 adds to the [OH] (you know Ba2+ doesnt affect) then you use the new [OH-] to find the [H30+].

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Generally if your molecule has more than a few atoms its going to be listed in the order that it is formed so it generally isn't a problem, you just gotta make sure everything works out charge wise and octet rule wise. Regarding shape, you just consider one "central" atom at a time.

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Just count the # of electron densities on the atom in question and count the orbitals to hybridize from there ie s, sp, sp2, sp3

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The kinds we are doing right now are acid-base titrations but there are others like Redox Titrations, Precipitation Titrations. Complexometric Titrations.

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AXE formula is used only regarding a single atom as the central atom, you can't have two As, so it simplifies it for us so all the X and Es are directly attatched to the central atom

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literally pKa just means the -log of the concentration of the products over the concentration of the reactants

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p just means -log of something, so for pH that something is the concentration of H+ or H3O+ and the pOH is substituting in the concentration of OH-

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It's hard to put down on paper, but the electrons making the bond are being shared with other atoms so the bond is only inbetween those two atoms half the time

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It kinda just squeezes itself into the H-N hydrogen bond in the backbone between two guanine or two adenine, causing a kink that prevents DNA replication

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Yes only one O2 can bind to each coordinate structure at a time

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just draw a lewis dot structure of the molecule, make sure to add the extra charge somewhere, and then count the electrons directly touching the atom and find the difference between the number of electrons its supposed to have in a neutral state. Do that for both, and experiment with the bonds and t...

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Ka is the concentration of the product over the concentration of the reactant.

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5 ligands, the oxygen it picks up acts as the 6th completing the octahedral shape

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if the molecule in question is able to both accept a proton and give a proton then it is amphoteric as a general rule.

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Generally in an equation you can look for the more electron deficient molecule of the two assuming its a lewis acid base reaction

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Same thing with lewis and bronstead definitions, both mean essentially the same thing, just one is a more specific definition

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The Bronstead-Lowry definition of acids and bases are PROTON donors/acceptors. acids being proton donors and bases being proton acceptors

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adding on, you can test for amphoteric substances by attempting to add or remove protons from the molecule.

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A bronstead acid donates a proton (H+) while a lewis acid takes electrons

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No but for some compounds they are useful to know for identification purposes

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An amphiprotic substance is one which can both donate hydrogen ions (protons) and also accept them like water. Amphoteric means that they have reactions as both acids and bases.

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Because they are directly overlapping with the orbitals. Pi bonds are merely parallel with the orbitals

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You mean molecular shape? VSEPR is plenty good enough

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You always take them into account but if there is a greater intermolecular force that is stronger you consider those instead such as dipole-dipole.

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The seesaw shape occurs when you have 5e density clouds with one lone pair.

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Hydrogen is just a weird element in general and doesn't follow a lot of the conventional rules of the periodic table.
thats why they put hydrogen all the way in the left corner even though its not an alkali metal

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what do you do when you only need 2 of the p orbitals to hybridize, do you just include the third one anyways or does it stay a p orbital.

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What does Vsepr stand for

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if when you consider what Atom to make a lone pair you consider the bond angles in reference to the other atoms why don't we take one from the axial plane say from a trigonal bipyramidal because its bond angle is 90 compared to the equitorial plane one of 120?

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starting from a pentagonal bipyramidal if you turn 3 into lone pairs where would you put the third lone pair? would it still be on the equatorial plane? or would it need to be an axial because of the lone pair repulsion?

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does the surface area of the dipoles matter more than having multiple dipoles attached at once in terms of strength of the intermolecular forces?

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Why do double bonds restrict rotation around an atom?

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Why does carbon monoxide have a +1 charge on the oxygen and a -1 charge on the carbon?

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Why is oxygen less electronegative than nitrogen?

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What's the difference between dipole-dipole forces and induced dipole-induced dipole forces? I could not quite grasp this concept in the lecture

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When do London dispersion forces take priority in bonds?

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why is it that an anion has a larger radius than its parent atom, I thought that when we add electrons the attraction gets stronger with the nucleus and it gets pulled in making it smaller.

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For drawing the lewis structure of ClO, why is it that the unpaired electron is on the chlorine instead of the oxygen, which makes the formal charges -1 and 1 instead of it being on the oxygen which would make it 0 and 0

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In the case of oxygen and carbon, you would say that they are sharing their electrons because it is a covalent bond. If it were a scenario where there were ionic bonds then you could say that atom A took one electron from Atom B

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electrons that are farther away from the nucleus are easier to remove because they are less affected by the pull of the positively charged protons in the nucleus. Sort of like gravity, although idk how far that analogy can go

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The atom with lowest ionization energy because they pull other atoms toward it with its electrons that it shares

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is it 2- or -2 I've seen it both ways and idk if one is right and why

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We can obtain oxidation numbers by arbitrarily assigning the electrons of each covalent bond to the more electronegative atom in the bond. This is in contrast to the Formal Charge which divides each bonding pair equally without concern for which atom may be more electronegative.

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Balmer series lies in the visible spectrum, Lyman series lies in the UV spectrum. The graphs showed the shooting out of energy packets from electrons jumping from one energy level to another.

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Basic ones we should be able to figure out, but in general we will be given the molecular formula in questions. Most of the words are just flavor text anyways

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Just look at what they are using in the question, cause if you understand what it represents then you can just use dimensional analysis and be done with that step, you shouldn't need to guess

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yes as long as you have the correct answer and the grader can tell what you did then you'll get credit

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which periodic table should I use in terms of to which decimal place cause a lot of them differ a lot.

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