CHEMISTRY COMMUNITY

Michelle Song 1I

You squareroot Kw to find the concentration of hydronium ions and take the negative log of that.

Michelle Song 1I

kennedyp wrote:
Michelle Song 1I wrote:I don't think you can multiply both sides in k1 cause the left side of the Van't Hoff equation is ln(k2/k1) so you'd have to change that to ln(k2)-ln(k1) and add ln(k1) to both sides.

Oh okay my bad!! :(((

Don't worry about it! It's an easy mistake

Michelle Song 1I

I don't think you can multiply both sides in k1 cause the left side of the Van't Hoff equation is ln(k2/k1) so you'd have to change that to ln(k2)-ln(k1) and add ln(k1) to both sides.

Michelle Song 1I

Would the fact that two moles of NOBr are produced affect the rate law?

Michelle Song 1I

Yes, it could happen if they all depend on the presence of a catalyst.

Michelle Song 1I

If I want to talk to my TA about Test 2, could I do so over email?

Michelle Song 1I

Dear Dr. Lavelle, Thank you so much for all the effort you've put into this class and in helping your students succeed. It was really helpful to have access to Chemistry Community and all the review sessions and I really appreciate the amount of work it takes to organize all of that and how dedicate...

Michelle Song 1I

The integrated rate law equations allow you to find the concentrations of reactants in regards to time and vice versa.

Michelle Song 1I

Unless the question states otherwise, it's seconds.

Michelle Song 1I

The order of a reaction tells you how the rate of that reaction changes in response to changes in the reactants' concentrations.

Michelle Song 1I

I think a pseudo rate law helps you find the order of an individual reactant in a reaction. You can use it when the concentrations of the other reactions are so large that a decrease in concentration doesn't really affect them, allowing you to focus on a single reactant.

Michelle Song 1I

It's moles per liter per time in sec. However, the units for k will change depending on what order of reaction it is.

Michelle Song 1I

It tells you how (or whether) changes in the concentrations of products will affect the rate of reaction.

Michelle Song 1I

An intermediate was formed (and then used up) by the reaction, so it doesn't show up in the rate law.

Michelle Song 1I

Consider both Kinetics and Thermodynamics?

Michelle Song 1I

How come the cell diagram in 6L.3 part d leaves out water? Is there ever a time we should include water, or any liquid, in a cell diagram?

Michelle Song 1I

Couldn't make it to Lyndon's workshop, is anyone willing to share the problems? Or anything he said that would be good to know?

Michelle Song 1I

If you need to write a cell diagram and a half-reaction doesn't have a solid, you can use platinum.

Michelle Song 1I

I believe Dr. Lavelle may have been referring to the Fe half-reaction, in which both the product and reactant are in solution.

Michelle Song 1I

Yeah you can pretty much assume anion is left and cathode is right unless the question is worded in a way that implies differently.

Michelle Song 1I

The electrons flow from the anode to the cathode.

Michelle Song 1I

J Medina 2I wrote:What are basic conditions?

Conditions where the pH is above 7

Michelle Song 1I

n is the number of moles of electrons, which you can find after balancing the half reactions.

Michelle Song 1I

They're the same number, just different sig figs (which shouldn't matter since it's a constant)

Michelle Song 1I

The equation for overall cell potential already takes into account that the values for standard reduction potentials that are given are all positive, which is why you don't have to change the sign before inputting it into the equation.

Michelle Song 1I

It's the number of electrons transferred, which you can find in the half reactions (after balancing them).

Michelle Song 1I

Adding on to the people above me, Faraday's constant is the charge on a mole of electrons, so the expression nFE is just the total amount of charge multiplied with the average amount of Joules per charge, which gives work.

Michelle Song 1I

For acidic reactions you add H+ to balance out the hydrogen atoms and in basic reactions you add OH- to then cancel out the H+ ions.

Michelle Song 1I

Yes, kinda like in math, whatever you do to one side you should do to both.

Michelle Song 1I

My guess for some of your questions would be since Br is being oxidized, you can assume that O3 is reduced, which kinda makes sense considering it loses an oxygen.

Michelle Song 1I

Shouldn't the oxidation state of oxygen in O2 be zero?

Michelle Song 1I

Adding an inert gas will not cause the reaction to shift in either direction.

Michelle Song 1I

The way you determine is by looking at the units you have.

Michelle Song 1I

Do you mind posting the entire question?

Michelle Song 1I

Work done by the system is associated with an increase in volume (and, therefore, has a negative sign) and work done onto the system is associated with a decrease in volume (resulting in a positive sign).

Michelle Song 1I

q would be positive if heat is being added to the system and negative if heat is being removed. w would be positive if work is done by the system and negative if work is done on the system. what is an example of work being done on or to the system? An example of work being done on a system would be...

Michelle Song 1I

In a closed system, energy is exchanged with its surroundings, but matter isn't, such as a sealed beaker of water. In an isolated system, nothing is exchanged with the surroundings, like the combustion of glucose in a bomb calorimeter.

Michelle Song 1I

It is the final internal energy minus the initial internal energy of the system.

Michelle Song 1I

Because it exchanges energy and mass with its surroundings.

Michelle Song 1I

Hey, I forgot that we could pick up our finals this week and I was wondering if I could pick mine up next week?

Michelle Song 1I

Sara Richmond 2K wrote:Yes, I am sure that I am looking at the right solution manual question. The answer to part A is actually 5. I have included a screen shot of my work to show how to get 5 for part A.

Oh whoops, I assumed that NH4Cl dissociated completely, sorry.

Michelle Song 1I

You should know that strong acids dissociate completely, which is why they don't have Ka constants, and thus result in solutions with higher H+ concentrations. Thus, if you are comparing two strong acid solutions, you can expect the one with a higher molarity to be more acidic. So is there a chart ...

Michelle Song 1I

Equilibrium constants are calculated using concentrations (or partial pressures, depending), so you could find the number of moles of reactants and product at equilibrium for this reaction, but you would have to convert them to concentrations in order to find the equilibrium constant.

Michelle Song 1I

If Q is less than K that means the ratio of products to reactants is too low and the reaction will shift towards the products. If it is more than K then the reaction will shift towards the reactants.

Michelle Song 1I

I believe that anytime the the concentration of H30+ = concentration OH- is considered neutral even if the ph isn't 7, which is neutral for water at room temperature. If kw changes because of a change in temperature then we should expect the ph scale and what is acidic, neutral, and basic should al...

Michelle Song 1I

I don't have the solutions manual in front of me so I can't check, but are you sure you're looking at the right solution? The solutions manual appears to be saying that the answer for part a is 5.00, and that's not the pH of 0.19 M NH4Cl.

Michelle Song 1I

You should know that strong acids dissociate completely, which is why they don't have Ka constants, and thus result in solutions with higher H+ concentrations. Thus, if you are comparing two strong acid solutions, you can expect the one with a higher molarity to be more acidic.

Michelle Song 1I

Noble gases like Neon and Argon are inert.

Michelle Song 1I

It depends on how you change pressure. If you add pressure by decreasing the volume of the system, then you're also increasing the concentrations of the reactants and products, thus making the reaction shift to whatever side has the least number of moles (and vice versa if you decrease pressure by i...

Michelle Song 1I

In the cases where Kw is a different value than 1.0 x 10^-14, assuming that [OH] still equals [H3O] and vice versa, wouldn't that mean that both the pH and pOH of the system are either lower or higher than 7? For example, if the Kw was higher than 1.0 x 10^-14, since [OH] = [H3O], wouldn't both of t...

Michelle Song 1I

Renee Grange 1I wrote:The divide by 100 in order to convert pKa to bar. 1 pKa = .01 bar.

Thank you! Did he mention this in lecture?

Michelle Song 1I

VPatankar_3L wrote:Yes I think you should always convert from Pa to atm or bar before you continue with calculations.

Ah okay, thank you! Did Dr. Lavelle mention this in lecture?

Michelle Song 1I

When calculating the equilibrium constant, the solution divides each of the values given on the plot (which are in kPa) by 100. Is this to convert it from kPa to atm? And if so, does that mean gas equilibrium constants can only be calculated using partial pressures in atm?

Michelle Song 1I

I was wondering about this too. The book gives 3.2 x 10^-12 as the answer because it multiplies 3.1 by 10^-3, which I think implies that it has something to do with units. However, the units of 3.1 are mol*L^-1, which are the same units the values in the other parts had and those values weren't mult...

Michelle Song 1I

Whatever is inside the brackets is part of the coordination sphere.

Michelle Song 1I

cis molecules have the same groups on one side and trans molecules have them on opposing sides.

Michelle Song 1I

DMuth_1J wrote:if coordination number is the number of bonds, then what is valence?

Valence is the number of electrons an atom/ion has in their outer shell

Michelle Song 1I

I remember Dr. Lavelle still used the equilibrium arrows for a reaction with a strong acid in water though. I can't remember what he said when he explained why.

Michelle Song 1I

The one with the hydrogen ion is the acid and the one without is the base

Michelle Song 1I

ATingin_3I wrote:
ashwathinair wrote:You should know cisplatin has a different structure than the trans version of the molecule because of sigma and pi bonds and the lewis structures of each.

so what would transplatin be used for?

Nothing in particular

Michelle Song 1I

What exactly does the suffix "-dentate" refer to? "Dentate" kind of means "bite", which refers to the bonds that form between the ligand and the central ion (a bond is similar to the ligand "biting" onto the ion). So a polydentate is a "ligand" that...

Michelle Song 1I

Their bonds tend to be more polar, making them more easily deprotonated.

Michelle Song 1I

Once it's in water, the hydrogen ions will dissociate.

Michelle Song 1I

Cisplatin is used in a certain kind of chemotherapy. It stops DNA from replicating by binding onto the guanine residues. It can only bind when the DNA is replicating, which is usually DNA in cancer cells. However, it can also affect healthy cells with replicating DNA.

Michelle Song 1I

Would you mind posting the homework question and solution you're talking about?

Michelle Song 1I

Probably, so long as you label them

Michelle Song 1I

Probably about as important as knowing how to name a compound, considering it's pretty much the same information

Michelle Song 1I

It bonds to the central ion in more than one place

Michelle Song 1I

I agree, the names of the ligands still have to be in alphabetical order in the formula

Michelle Song 1I

Start with naming the ligands

Michelle Song 1I

It doesn't matter which one you calculate first.

Michelle Song 1I

The smaller and more highly charged a cation is the more polarizing power it has.

Michelle Song 1I

A general rule to remember is that if the electronegativity difference is >2.0, the bond is ionic and if it's 1.5> and >.5 then it's polar covalent. If it's <.5 then it's nonpolar covalent.

Michelle Song 1I

Boron and Aluminum are also exceptions in that they can form only 3 bonds.

Michelle Song 1I

I go with the least electronegative atom, which tends to be the atom with the lowest ionization energy except in the case of nitrogen and oxygen, in which oxygen has a lower ionization energy but is more electronegative (in this case, I believe nitrogen is used as the central atom).

Michelle Song 1I

I'm pretty sure δ is used to indicate the charge on the atoms and the dipole arrows are drawn going from the positive to negatively charged atoms.

Michelle Song 1I

You probably only have to know the basics of the shapes of the orbitals, like how s-orbitals are a sphere, p-orbitals are like dumbbells, and so on. Also the number of nodes for each type of orbital. I'm pretty sure we don't need to know about f-orbitals though.

Michelle Song 1I

Yes, in the review session I went to today, the TA said we didn't have to specify p_x, p_y, p_z

Michelle Song 1I

To add on to previous responses, m_x is the spin of the electron and can be either positive or negative 1/2

Michelle Song 1I

I assume it is Li+ since I think for cations, they have more polarizing power with higher charge and smaller radius.

Michelle Song 1I

How would you find the frequency of a particle that is not a photon?

Michelle Song 1I

Because Na also has a smaller effective nuclear charge than Al, and they have the same number of "shielding electrons".

Michelle Song 1I

It also doesn't include lone pairs of electrons.

Michelle Song 1I

A high ionization energy means that it is difficult for it to lose electrons, thus, it is unlikely that a nonmetal will gain a positive charge.

Michelle Song 1I

Metals tend to form cations and nonmetals tend to form anions, meaning metals will tend to donate electrons to nonmetals.

Michelle Song 1I

Adding on to what the person above me said, it's also important to remember that transition metals in the d-block will lose electrons in the s-orbital first.

Michelle Song 1I

Increasing the energy of the photon (or decreasing its wavelength) is needed to eject an electron. Increasing the intensity of light simply increases the number of photons and, if the energy in one photon isn't enough, it doesn't matter how many there are since none of them will launch an electron (...

Michelle Song 1I

The Lyman series is a series of transitions that result in emission lines and is defined by the fact that the nf is 1. I haven't seen it used to describe wavelength absorption, but if it is I would assume that it applies to transitions where the ni is 1.

Michelle Song 1I

This is kinda a simple way of thinking about it but atoms want to have a full electron shell and since s-block metals only need to lose 1-2 valence electrons in order to have a full shell they really want to lose them, which is why they react more easily.

Michelle Song 1I

Yes, constructive and destructive interference apply to sound (which is a longitudinal wave), you can use tuning forks to demonstrate this (it's fun to play around with them).

Michelle Song 1I

Do we know when the midterm is yet?

Michelle Song 1I

The photoelectric experiments support the particle behavior view, Young's double slit experiment (or any experiments that involve the diffraction of light) supports the wave behavior view (although I remember something about how light will act differently when its being observed). Someone above alre...

Michelle Song 1I

One difference is that the photoelectric experiments involve completely removing the electron from the atom and measuring the properties of the removed electron, whereas atomic spectroscopy only involves the transition of an electron in between the energy levels of an atom. The electron can be excit...

Michelle Song 1I

It does seem that visible light is most commonly used, but any type of light can be used to cause the photoelectric effect so long as its wavelength is shorter than 683 nm.

Michelle Song 1I

The above reply is true if light acts simply as a wave, as the photoelectric experiment has demonstrated, light also acts a particle, in which case increasing its intensity would be increasing the number of photons.

Michelle Song 1I

Each series contains the transitions of an electron going from a higher energy to a specific lower energy level. For the Lyman series, the lower energy level is n = 1, for Balmer, the lower energy level is n = 2 and so on. So essentially, what is common to the lines within a series is that they end ...

Michelle Song 1I

Amir Bayat wrote:Alright, that is what I believed it to be.

Thank you.

No problem, glad I could help.

Michelle Song 1I

My TA said that most TAs won't care about sig figs when grading homework, and I would personally go with following the sig fig rules because then, if you actually do get points taken off, you have a good defense for your answer as the established rules should hold precedence over what the solutions ...

Michelle Song 1I

I believe so, I'd recommend looking up homonuclear molecules to learn more.

Michelle Song 1I

The mass of oxygen will be the same whether you convert from moles of O2 or O as the number of moles of O is twice the number of moles of O2 and the molar mass of O is half the molar mass of O2.

Search found 102 matches