CHEMISTRY COMMUNITY

sallina_yehdego 2E

The units for k in a second order reaction is M^-1s^-1

sallina_yehdego 2E

Catalysts lower the curve of the reaction.

sallina_yehdego 2E

You're correct. You don't add the zero order.

sallina_yehdego 2E

^I agree. When solving for one experiment, you determine the numbers you are doing the calculations with by seeing which other variables are constant. So for example, if you are trying to find the rate of A, you look at the chart to see when B and C are constant in an experiment and then divide thos...

sallina_yehdego 2E

Increasing activation energy means that the reaction rate is increasing because you are making the reaction slower and causes more energy to be needed.

sallina_yehdego 2E

What's the main difference between fast and slow steps and how can you tell them apart if they aren't mentioned? Also, why is the slow step the one that determines the reaction?

sallina_yehdego 2E

Are the units for zero order reactions M/s or mol/(L*s)?

sallina_yehdego 2E

k is products over reactants, so if k > 1, then the products are favored and the forward rate is faster; however, if k < 1, then the reactants are favored and the reverse rate is faster.

sallina_yehdego 2E

Yes, they are used for elementary step rate laws, but always keep in mind you cannot use it when you're trying to solve for the rate law of the overall reaction because the coefficients may not always line up.

sallina_yehdego 2E

The purpose of kinetics is to see what various substances affects the rate of the reaction and how fast the reactants are turned into products. So basically what you pretty much got it.

sallina_yehdego 2E

Yes, negative orders are possible and just means that whatever the substance is, it decreases and cases the reaction rate to increase. I had the same confusion, but a TA told me to get familiar with negative orders and fractions.

sallina_yehdego 2E

Ultimately, a salt bridge is what helps maintain a battery and allows it to work. When adding a salt bridge, it the elements K+ favors the cathode and CL- favors the anion, and helps the stabilize the flow of electrons between the two.

sallina_yehdego 2E

If a problem were to ask you to find the value of K or Q, how would you do this when using Nernst's equation?

sallina_yehdego 2E

First, you should always see if the equation is balanced out or not. From there, you go to each compound/ion and find the charge of each one. From there, you compare the reactants with the products to see which are being reduced and which are being oxidized. The reducing agent is the one that gets o...

sallina_yehdego 2E

Just for clarification, why do isothermal systems use the constant R and why don't non-isothermal systems use R?

sallina_yehdego 2E

Molecules that are more complex (larger in size) are the ones with higher entropy. Also, residual entropy is the difference in entropy (left over in the system) when it is at absolute 0 Kelvin.

sallina_yehdego 2E

Larger compounds/atoms are more complex and larger in weight, allowing it to have accessible vibrational energy levels. This is what causes it to have higher entropy.

sallina_yehdego 2E

Why aren't there any delta symbols for the standard molar entropy formula? Also, why are the components always positive?

sallina_yehdego 2E

Just to be clear, does low temperature mean there's an increase in entropy? Or is it the opposite?

sallina_yehdego 2E

Why is steam hotter than boiled water? It was discussed in lecture, but I still am confused with the concept.

sallina_yehdego 2E

Adiabatic means q=0, which means delta U=w

sallina_yehdego 2E

Isochoric means delta V=0, which means w=0 and delta U=q

sallina_yehdego 2E

Isobaric means that delta P=0 or qp=delta H, which means that delta U=delta H—P*delta V

sallina_yehdego 2E

When do you know when work is negative or positive?

sallina_yehdego 2E

On an exam, when conducting a problem using the equation, q=g*Csp*deltaT, are we supposed to memorize the specific heat (Csp) even if the problem doesn't give it to you, or will it be given?

sallina_yehdego 2E

I understand the concepts of systems, but what's a good example of an isolated system?

sallina_yehdego 2E

What is the difference between q and qp?

sallina_yehdego 2E

Why aren't heat and work considered a state property?

sallina_yehdego 2E

What does the p represent in the expression "qp"?

sallina_yehdego 2E

When conducting the ICE table, are aqueous and gas compounds allowed only?

sallina_yehdego 2E

What's the difference between Q and K??

sallina_yehdego 2E

Why does a change in temperature affect K and not a change in pressure or concentration?

sallina_yehdego 2E

When working on problems dealing with partial pressure, should we always write a "P" before the constant? (e.g. Kp= PCO2) Because it was shown to do it in lecture?

sallina_yehdego 2E

In lecture we went over how if there is a large equilibrium constant, it is a result from it having less product because it is stable; however, if the product is more than the reaction, will it make it a smaller equilibrium constant? And would it count as a reverse reaction?

sallina_yehdego 2E

It depends on the information given in the problem. It will most likely ask for you to find either or.

sallina_yehdego 2E

What does the R represent in the equation PV=nRT? and what are the units?

sallina_yehdego 2E

Why is HF not considered a strong acid??

sallina_yehdego 2E

Just to be clear, strong acids usually have weak conjugate bases and strong bases usually have weak conjugate acids right?

sallina_yehdego 2E

If a compound consists of resonance structures, can that help distinguish if it's a weak or strong acid or base?

sallina_yehdego 2E

Yup! When given pH and want to find pOH, you simply subtract the pH by 14, due to the fact that pH and pOH together equal 14.

sallina_yehdego 2E

I noticed in lecture, Professor Lavelle wrote hydroxide ion as [-OH], instead of [OH-]. BY moving the charge, does it alter the compound? Are they both the same or are they different?

sallina_yehdego 2E

THANK YOU!!!!

sallina_yehdego 2E

You first find the oxidative number of the compound (given) and are usually given another oxidative number of one of the atoms or you must know (e.g. (NH3) is 0). From there, you find the difference between the oxidative states to find the oxidative number of the missing one(s).

sallina_yehdego 2E

What are the relationships between strong and weak acids and bases with water? Do they dissociate or not? Does one dissociate faster than the other?

sallina_yehdego 2E

Do the definitions of Bronsted acids and bases and Lewis acids and bases relate to oxidation and reduction reactions? Just thought I saw a connection with a bio topic and chem topic.

sallina_yehdego 2E

Here's a website that can also help.

http://chemed.chem.purdue.edu/genchem/t ... vsepr.html

sallina_yehdego 2E

The two models are pretty similar, but I first start by drawing out the lewis structure in the most linear shape as possible. Then I add the dotted and darkened lines as much needed. I also circle in the lone pairs. From there, I find it easier to the the VSEPR shape. Hope this helps.

sallina_yehdego 2E

Fluorine is the element with the highest electronegativity

sallina_yehdego 2E

Do resonance structures also occur in VSEPR models? Like when you are drawing them with the dotted lines?

sallina_yehdego 2E

When all four lobes of the d orbitals interact with each other making it a covalent bond.

sallina_yehdego 2E

Single bond = one sigma bond, double bond = one sigma bond and one pi bond, and triple = one sigma bond and two pi bonds

sallina_yehdego 2E

Is there a difference in length/distance for sigma and pi bonds?

sallina_yehdego 2E

If a d-block does appear, would writing the hybridization out like sp^3d be correct or do we have to put the d in the beginning first like dsp^3?

sallina_yehdego 2E

I don't believe so, but it's always good to know how to draw the 3D model

sallina_yehdego 2E

I think you have to memorize those as well. Or you can look at the shape and determine it from there, but you would have to draw the shape correctly if you are looking doing it that way

sallina_yehdego 2E

What's the difference between polarizing power and polarisability?

sallina_yehdego 2E

Are we supposed to draw all of the resonance structures even if the problem does not ask?

sallina_yehdego 2E

When drawing out the Lewis Structures, are we supposed to add the charges on the atoms even when it's not asked in the problem?

sallina_yehdego 2E

I understand the trend of electronegativity, but what is the purpose of electronegativity?

sallina_yehdego 2E

There shouldn't be any exceptions in regards to periodic trends and drawing Lewis structures

sallina_yehdego 2E

When drawing Lewis Structures for polyatomic molecules, what are the rules if charges exist?

sallina_yehdego 2E

Why are H, He, Li, and Be exceptions to the octet rule?

sallina_yehdego 2E

We haven't mentioned in Lecture 1 yet, but how do you find the number orbital of in a sub shell??

sallina_yehdego 2E

Will the values of the symbols be given on the exam or should we just memorize them? (e.g. Planck's constant or speed of light)

sallina_yehdego 2E

For week 3, are we choosing another set of 7 questions from the Quantum World chapter or do we move on to the Chemical Bonds chapter?

sallina_yehdego 2E

I would just stick with v because that's what Lavelle has been giving us.

sallina_yehdego 2E

Why is this equation negative again? I know Professor Lavelle mentioned this in class, but can someone please refresh it to me?

sallina_yehdego 2E

Can someone please narrow down the significance of photoelectric effect? I still don't get it.

sallina_yehdego 2E

What does the h in E=hv represent again??

sallina_yehdego 2E

Quick Question: Are we supposed to write down the questions for the textbook problems when doing the homework??

sallina_yehdego 2E

You complete any 7 problems that you want to do

sallina_yehdego 2E

False alarm. I figured it out (:

sallina_yehdego 2E

If I don't know the states of atoms when writing a chemical equation, what should I do? Leave it blank or just do an educated guess?

sallina_yehdego 2E

Anyone willing to give a simpler definition of the Law of Conservation of Mass?

sallina_yehdego 2E

Hey guys. Am I the only one that is confused about where the problems are located in the textbook? What pages are the textbooks problems in, for the 6th and 7th edition??

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