CHEMISTRY COMMUNITY

Jorja De Jesus 2C

Le Chatelier's Principle refers to how chemical reactions adjust to go in the direction that will minimize the effect of changes. This can occur if the physical parameters pressure and temperature are changed. I think you can check using the equation PV=nRT.

Jorja De Jesus 2C

You don't include H2O if it is in solid or liquid form. Solids and liquids are not counted in ICE tables.

Jorja De Jesus 2C

You use the first one (8.314 J/K*mol) because it will allow you to cancel out temperature and Faradays constant, then you would be left with J/C which equals volts.

Jorja De Jesus 2C

Why does the work of expansion at a constant pressure use volume for the integral?

Jorja De Jesus 2C

What do you plug in to the equations for these methods if you aren't given the $\Delta H^{\circ}_{f}$ or the $\Delta H^{\circ}_{B}$ values? How do you use the equation to determine this?

Jorja De Jesus 2C

Yes, you do not include H2O. In a cell diagram I think the molarity of the aqueous species already shows that there is a liquid involved. In cell notation you also do not include water (the set up is electrode material|aqueous species||aqueous species|electrode material).

Jorja De Jesus 2C

Are you referring to the frequency factor? I think it is A=Zp but it is not usually calculated so it is just left as 1.

Jorja De Jesus 2C

Does enthalpy have its own equation or can you only use the three methods to find it (such as Hess's law)?

Jorja De Jesus 2C

When the half reactions are both reduction reactions or both oxidization reactions you change one of them by switching them around and changing the sign of the cell potentials right? How do you know which one to change so that they are no longer the same?

Jorja De Jesus 2C

Does the Arrhenius equation find the activation energy and then could the equation $lnK=(-E_{A}/RT)+lnA$ be used on the activation energy? Also what does exp stand for in the Arrhenius equation?

Jorja De Jesus 2C

If a step refers to a chemical equation how do you know which step it is from looking at the equation? How can you tell if it is slow or fast? How can you tell if it is an elementary step or a non-elementary step?

Jorja De Jesus 2C

When using R (the 8.314 $J*K^{-1}*mol^{-1}$ version) with the Nernst equation, what should the units be in the end and how do the units cancel out to that? Also could the other variations of R be used in the Nernst equation too?

Jorja De Jesus 2C

905415863 wrote:Conjugate seesaw has to do with conjugate acids and bases. A weak acid will have a strong conjugate base. A strong acid will have a weak conjugate base. You can see how this is metaphorically related to the idea of a seesaw.

So the conjugate seesaw isn't referring to K_AK_B=K_W?

Jorja De Jesus 2C

If q is heat what is qP? What does P stand for? Is it pressure?

Jorja De Jesus 2C

How do you get from the conjugate seesaw to other equations such as pK_A+pK_B=pK_W to pK_W =pH+pOH? Should values for pK_A, pK_B, and pK_W be within 0-14 like pH and pOH?

Jorja De Jesus 2C

What does the subscript w mean in Kw? Why do the acid and base constants multiply to get Kw? Also is it a capital or lowercase W?

Jorja De Jesus 2C

Is decay just the breaking apart of different elements in a compound? If so does growth look like? Also how do reduction and oxidation relate to these if possible?

Jorja De Jesus 2C

What is the difference between k' and $k_{r}$ ?

Jorja De Jesus 2C

So if it's the instantaneous rate of change, then the differential rate law is the derivative of that and is the regular rate law, then what is the average rate? Is it the second derivative? Is it even the same as the average reaction rate or am I connecting the concepts in the wrong way?

Jorja De Jesus 2C

Is the integrated rate law instantaneous?

Jorja De Jesus 2C

What is the difference between the reaction rate and the average reaction rate if the reaction rate is also considered an average of the change in concentration? Wouldn't they both be the same even if the average reaction rate is measured on an interval?

Jorja De Jesus 2C

When would you use K instead of Q? Does the electron flow stop at equilibrium? If so why use K?

Jorja De Jesus 2C

What exactly is the difference between electrolytes and electrodes and do they even relate to each other? Why do they affect voltage differences?

Jorja De Jesus 2C

When calculating voltage why must there be a plus sign in front of the answer if it is positive? Why is it not the same without the plus sign?

Jorja De Jesus 2C

What is the purpose of reversing one of the half reactions to change the sign of the cell potential?

Jorja De Jesus 2C

Does the electromotive force only include electron flow that goes from left to right (in galvanic cells)? Or is it any direction?

Jorja De Jesus 2C

If batteries are designed to flow in one direction, are galvanic cells the same? Can electrons only flow in one direction or can they go both ways? Does the salt bridge make it go both ways?

Jorja De Jesus 2C

Are there other galvanic cells like concentration cells that have special conditions?

Jorja De Jesus 2C

When applying the Nernst equation, why is it better to have less reactants and more products? Is it because of Le Chatelier’s principle? What happens if there are more reactants and less products?

Jorja De Jesus 2C

When writing equations based off what is given in cell notation, what is the best way to determine which elements to leave out? For example in the standard hydrogen equation, you leave out platinum when but use the rest of the elements.

Jorja De Jesus 2C

What does it mean when you put a degree symbol or knot symbol with delta G or any other variable? What is the difference between that and when the symbol is used for temperature?

Jorja De Jesus 2C

Is the flow of electrons electricity? Is the term electricity interchangeable with the term electric energy?

Jorja De Jesus 2C

Do you put all the reactants of each reaction together and all the products of each reaction together?

Jorja De Jesus 2C

When simplifying half reactions what does it mean to cancel out species?

Jorja De Jesus 2C

I think when the solution is acidic, you use H+ to balance H in the reaction and when the solution is basic you use H2O to balance H.

Jorja De Jesus 2C

Why is it lnk1 at T1 and lnk2 at T2? Are both K and T changing?

Jorja De Jesus 2C

Why do you need to pay attention to whether or not the solution in a redox reaction is acidic or basic?

Jorja De Jesus 2C

Why do we multiply the half-reactions by the number of electrons gained or lost?

Jorja De Jesus 2C

In example 6K.1, why is the C2H2O4 turned into H2C2O4?

Jorja De Jesus 2C

How do you do use Hess's law when only the main reaction is given?

Jorja De Jesus 2C

How do you simplify a cubic function to a quadratic function?

Jorja De Jesus 2C

What is the purpose of the fractions multiplied by R? For example Cp= (5/2)R; does this get plugged into $q=mC\Delta T$ or does it get put into U=3/2 nRT except the 3/2 would be 5/2? Also when do you know if it is Cp or Cv?

Jorja De Jesus 2C

In $-\int _{V1}^{V2} PdV=-nRTln(V2/V1)$ what is d? Is it a separate variable or is it dV (the derivative of V) and how do you find it? Also do V1 and V2 represent volume? If they represent volume how do they turn into the number of microstates?

Jorja De Jesus 2C

Are these referring to the shape of a molecule? If so why does the shape affect entropy?

Jorja De Jesus 2C

Is W just the number of microstates and are microstates just the number of atoms attached to the central atom of a molecule? If so how do you know which molecule you should be basing W on?

Jorja De Jesus 2C

How do you know whether heat is added or released just by looking at the equation?

Jorja De Jesus 2C

When creating ice tables, does it matter if the reactants or products are on a certain side (left or right)? When the equation is not given how do you know what side to put the reactants/products?

Jorja De Jesus 2C

Are ICE tables only used to calculate molarity? Or can there be instances where the ICE table will be used to find something other than molarity such as mass, and then the mass would have to be converted into molarity?

Jorja De Jesus 2C

Other than in aqueous solutions, in what other situations would $\Delta V$ equal 0?

Jorja De Jesus 2C

I’m not exactly sure what a piston is and how that works in the diagram. A piston is the disk/cylinder looking thing that can move up and down the container and push against or pull away from the system decreasing or increasing pressure and volume. The diagram I'm referring to is the one from the l...

Jorja De Jesus 2C

What are these terms referring to and what do the errors in S and W have to do with them?

Jorja De Jesus 2C

In lecture there was a diagram of three pistons showing how force and internal energy affect how energy increases or decreases in the system; some of the pistons have arrows pointing upwards in the section labeled D which is the change in volume and the change in area (I think). What do these arrows...

Jorja De Jesus 2C

Would systems with constant pressure be considered open systems and systems with constant volume be closed systems? If so when would a calorimeter with constant pressure become defined closed or isolated?

Jorja De Jesus 2C

Is force pressure per unit area or pressure times area?

Jorja De Jesus 2C

What do the orderly and disorderly motion of atoms look like? Wouldn't atoms just have disorderly motion, like how atoms behave in a gas? Or is that not what it is referring to?

Jorja De Jesus 2C

Do superheating and supercooling happen every time something heats up/cools too quickly?

Jorja De Jesus 2C

Since work is the opposing force x distance moved what can it affect? What is work not applicable to?

Jorja De Jesus 2C

When using the Hess's Law method, I know that the $\Delta H$ values are added together, but what exactly do you do to the chemical equations given?

Jorja De Jesus 2C

Does steam produce more severe burns than water because it changes phase once it touches your skin? Also how does whether or not the temperature is uniform affect this?

Jorja De Jesus 2C

When a buffer neutralizes something, does it take or give protons?

Jorja De Jesus 2C

What is the 5% rule and how do you apply it?

Jorja De Jesus 2C

When is concentration the only thing that affects K and when is it not the only thing?

Jorja De Jesus 2C

When using PV=NRT, would finding the equilibrium constant only apply to pressure? Or could you use [P]/[R] with all the other variables?

Jorja De Jesus 2C

When calculating the percent protonated, what is being protonated and when do you need to know if it is protonated?

Jorja De Jesus 2C

What determines whether we use a quadratic or a cubic function? Are the exponents determined differently than when the leading coefficients are used for the exponents?

Jorja De Jesus 2C

Other than the size of K, does anything else affect whether the equilibrium sits to the left or right?

Jorja De Jesus 2C

Is there a difference between partial pressure and just pressure?

Jorja De Jesus 2C

What values correlate with a, b, and c? Also what is the purpose of the quadratic equation? What does it calculate?

Jorja De Jesus 2C

Does volume affect pressure only when it is decreasing?

Jorja De Jesus 2C

If the C stands for change, C stands for the change of what? Is it the concentration? How do you determine what goes in the row for C?

Jorja De Jesus 2C

When do electrons get promoted? For example if there are two electrons in an orbital that have opposite spins and one of them gets moved so that all of them are parallel, when does this happen?

Jorja De Jesus 2C

What does pK stand for and what's the difference between it and others like pKw, pKa, $pK_{a}$ , $pK_{b}$ , $K_{a}$ , and $pK_{w}$ ? Also how do you calculate all of these?

Jorja De Jesus 2C

How can you tell if ligands can occupy more than one bonding site?

Jorja De Jesus 2C

How do you determine the oxidation number? Also how do you determine the overall charge of the molecule?

Jorja De Jesus 2C

When writing the equation for Lewis acid-base reactions, do you do anything differently compared to writing the equation of a chemical reaction that isn't an acid-base reaction?

Jorja De Jesus 2C

Are Bronsted acids and bases the opposite of conjugate acids and bases?

Jorja De Jesus 2C

What exactly are hydrogen bonding sites? Are they where hydrogen is just bonded to some element or where hydrogen can potentially bond with an element?

Jorja De Jesus 2C

What is the difference between hydrogen bonds and hydrogen bonding? For example, if hydrogen bonding (the intermolecular force) only occurs when H bonds with O,N, or F, would those be hydrogen bonds, would hydrogen bonded with an element other than those be a hydrogen bond, or would both kinds be hy...

Jorja De Jesus 2C

What is the difference between two hydrogen bonds and a double bond?

Jorja De Jesus 2C

Doesn't the double bond in amide already indicate that it has a stronger boiling point than N-H? (Amide has an N single bonded to a C, and then an H single bonded to the N and an O double bonded to the C) I thought that if the molecule has stronger bonds in it like a double or triple bond, it would ...

Jorja De Jesus 2C

Is it just complexes that can form rings?

Jorja De Jesus 2C

What is the difference between polydentate, bidentate, and ambidentate? What are they referring to when it comes to ligands?

Jorja De Jesus 2C

Are d-metals just metals with d orbitals? If not what does the d in front mean?

Jorja De Jesus 2C

Are the central atoms of complexes always a metal atom or ion? Are there cases where it is not a metal?

Jorja De Jesus 2C

What is the difference between the terms cis and trans?

Jorja De Jesus 2C

Do $\delta$ and $-\delta$ represent partial charge? How do you know where to put these symbols and when? Also do the arrows ( $\mapsto$ ) used along with these point from the negative to the positive?

Jorja De Jesus 2C

If the size of the atoms in a molecule affect the strength of intermolecular forces does that mean that the over all size of the molecule can affect the strength of intermolecular forces too? Do they follow the same trends?

Jorja De Jesus 2C

When drawing Lewis structures do you fill out the outer atoms with lone pairs first and then put the remaining on the central atom? What is the best way to tell if you should put lone pairs on the central atom or if double or triple bonds should be made?

Jorja De Jesus 2C

What's the difference between partial charges and formal charges? How do you calculate partial charges?

Jorja De Jesus 2C

When calculating formal charge, which atoms to you calculate first, the central atom or the surrounding ones? Do you add up all their charges in the end?

Jorja De Jesus 2C

Do the number of lone pairs on a central atom affect how polar a molecule is?

Jorja De Jesus 2C

If a lewis structure has atoms arranged around its central atom non-symmetrically then it is a polar atom right? What draws the line between symmetrical and not symmetrical? For example if there are 5 atoms around the central atom, the atoms could be arranged around it so that it can be either symme...

Jorja De Jesus 2C

How can you tell if they are more polar than another?

Jorja De Jesus 2C

Atoms have electron clouds and electron distortion is when that cloud gets distorted. Polarizability is how easily an electron cloud can be distorted. So if ions have high electron distortion that means that their electron cloud is distorted easily, and as a result they have high polarizability or h...

Jorja De Jesus 2C

Longer bonds are weaker and shorter bonds are stronger. Single bonds are the longest so they are the weakest; triple bonds are the shortest so they are the strongest. Double bonds are in the middle with both length and strength.

Jorja De Jesus 2C

I don't think you would have to calculate formal charge all the time, I think it would just be when it is being asked for in a problem. Another instance where you most likely will have to calculate it might be when you have to adjust the lewis structure so that all the atoms are stable at a formal c...

Jorja De Jesus 2C

Ionization energy and electron negativity (and electron affinity and atomic radius) are involved in what an atom does to its electrons when it becomes bonded with another atom. They are two different things but they follow the same trend. Ionization energy is the energy required to remove an electro...

Jorja De Jesus 2C

I don't think you have to write them in a certain order; it just depends on what is being asked for. If you are asked for the ground state electron configuration, you just write that out. If it asks for the electron configuration for a cation or anion, you will probably have to write the ground stat...

Jorja De Jesus 2C

It is mainly referring to the size of the atom. The larger the atom the larger the bonds, and the larger the bonds the weaker the bonds are. The smaller the atom the shorter the bonds, and the shorter the bonds the stronger the bonds are. So basically you just have to look at the atomic radius trend...

Jorja De Jesus 2C

I think your problem is that you set the calculator to SCI. SCI makes ALL the calculations in scientific notation. For example if you did 5 x 5, you wouldn't get 25, you would get 2.5x10^-1. I think that this is what would throw your answers off. So change your settings to the default settings. I th...

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