CHEMISTRY COMMUNITY

LianaHernandez1F

Just curious as to why catalysts aren't involved in in the thermodynamics? Is it because kinetics favors reactions with lower activation energies while thermodynamics favors more stable ones? This is because catalysts don't change the energy of the reactants or products. Therefore since thermodynam...

LianaHernandez1F

If a temperature is not given, can we assume we are solving at 25 degrees celcius? If temperature is not given it means it usually does not have an effect on the equation you are solving for. You could assume 25 Celsius since that is standard but I would definitely make sure that the equation does ...

LianaHernandez1F

I just had a quick question about conjugate acids and bases. I just wanted to know how we know which compound is the conjugate acid/base in the chemical reaction and also how this concept may come up when solving problems? The conjugate base is the acid minus its proton. A strong acid is completely...

LianaHernandez1F

Reading through these explanations confused me a little bit. If we were asked straight up: "Are H and S temperature dependent or independent" would you say they are temperature dependent since they do vary with large temperature changes? Yes because H and S are essentially standard values...

LianaHernandez1F

First, you would use the table to determine the ordering of each reactant. As changing the concentration of C has no effect on rate, it is of zero order. A is first order since the rate doubles when the concentration of A is doubled. B is second order because doubling the concentration of B causes a...

LianaHernandez1F

You can pick any trial, however some concentrations are more tangible to work with than others. Its really up to you.

LianaHernandez1F

The two things we mostly discuss in this class are electrolytic and galvanic/voltaic. The typical cell potential is positive because galvanic cells are always flowing from anode to cathode. In contrast, the flow in electrolytic cells is from cathode to anode, which typically results in a negative st...

LianaHernandez1F

When concentrations are changing at an excessive rate, a pseudo rate is taken into account. For instance, figuring out the rate when both A and B are changing and you know k[A][B] is challenging. In order to make the rate reliant only on the other, you make one much greater.

LianaHernandez1F

You determine these through experimental data. For example a question will provide you with numbers and information in order to calculate the rate law.

LianaHernandez1F

A particular reaction mechanism will go through all of its steps. We require the rate-determining step, sometimes known as the "slow step," in order to determine the rate law. Alternatively, if the situation demands it, we can decide the rate-determining step in light of the rate law. The ...

LianaHernandez1F

Making sure that the number of electrons acquired by the reduction half-reaction equals the number of electrons lost by the oxidation half-reaction is the process of balancing half-reactions. In most cases, this is accomplished by multiplying the half-reactions by coefficients so that the quantity o...

LianaHernandez1F

E nought is employed in typical circumstances. The abnormal cell potential is denoted by E. The relationship between E and E naught varies depending on how we modify the reactant and product concentration. For instance, the cell potential increases when we increase the reactants and reduce the produ...

LianaHernandez1F

When you have a lower standard reduction potential, you will have a stronger reducing agent. when you have a higher standard reduction potential, there will be a stronger oxidizing agent (but weaker reducing agent). This means they are inversely related.

LianaHernandez1F

The lone line depicts the boundary between two phases that are in contact with one another (including a porous wall in the middle instead of a salt bridge). A salt bridge connecting the anode and cathode is shown by the double line. On the left (anode) are the molecules that are being oxidized, and ...

LianaHernandez1F

Will K always change if the temperature changes?

LianaHernandez1F

I would definitely use whatever is on Lavelle's constants sheet because that is how he will calculate answers.

LianaHernandez1F

When would we use delta S naught as opposed to just delta S?

LianaHernandez1F

When would we assume that the change is "too small" to be considered?

LianaHernandez1F

I understand to use vent offs equation when calculating K but is this ONLY with temperature change. I know there are other ways to calculate K that's why I am wondering.

LianaHernandez1F

To determine if a compound is acidic or basic: Count the hydrogens on each component before and after the reaction to determine if it is an acid or a basic. If there are fewer hydrogens, then the substance is acid (donates hydrogen ions). The material is the base if the hydrogen count has increased ...

LianaHernandez1F

For these type of problems do we need to label all different types of bonds or does it not have to do with that necessarily?

LianaHernandez1F

Enot = RT/Nf ln is the result of solving for Enot with the cell at equilibrium, q=k (k). This can be entered into the E = Enot - RT/nfln(k) calculation for Enot. The result, E = RT/Nf ln(k) - RT/Nf ln(k), is simply zero.

LianaHernandez1F

State functions can be found by subtracting the final from the initial state. State functions also do not take into account the process to get from one to another. Work would not be a state function because it includes the work and path of a system.

LianaHernandez1F

Yes! It is safe to assume that constant temperature means it is isothermal. An isothermal reaction occurs at a constant temperature so there is no change in T values.

LianaHernandez1F

Insulated systems mean that heat can be transferred in and out of the system where as isolated systems mean there cannot be any heat or mass transfer.

LianaHernandez1F

I was wondering do we need to add negative signs or positive signs to certain equations depending on what the equation is talking about. For example in an equation talking about work being done by the system would we add a negative sign to the equation or leave it as is?

LianaHernandez1F

Hi! I think it depends on what the question is asking for and what units are given. Sometimes there are no moles within the question so you know which units you will use. Although different worksheets use different units, I think that for the test you should look for what units are being used in the...

LianaHernandez1F

The person under this post is saying that we have to do the combustion reaction for 1 mole of each of the equations but I am confused on how that would be done? Im not sure the steps for solving for the combustion reaction of 1 mole? Could someone please explain?

LianaHernandez1F

Most equations will never ONLY be positive or negative. These only indicate what the number is telling us. In terms of Delta H (also known as heat), negative values show that the equation lost heat. This means that it is an exothermic reaction. In the same reasoning, with a positive Delta H, the rea...

LianaHernandez1F

I believe we are only covering Outlines 3 and four which include the thermodynamic lectures. Not any electrochemistry though! Hope that helps!

LianaHernandez1F

My question is when do we know to use molarity and when do we not. Some equations require us to convert our units and some don't. What is the basis on which we decide to use molarity or not?

LianaHernandez1F

When do I know to use the ICE Chart as opposed to just doing the regular Kc equation?

LianaHernandez1F

I know we use Kc a lot in our problems but I'm confused to exactly what it represents?

LianaHernandez1F

If you click on your User ID and scroll all the way to the bottom you will see the "total number of posts", you can then click on this to view your exact posts.

LianaHernandez1F

The only thing that effects Kc is temperature. Otherwise the reaction will always be able to stabilize.

CHEMISTRY COMMUNITY

Search found 35 matches

Re: Catalyst

Re: Acids and Bases

Re: Acids and Bases

Re: Why are ∆H and ∆S temperature dependent

Re: Finding the rate of A, B, and C

Re: picking a trial

Re: Electrochemical cells

Re: Psuedo First Order

Re: Rate Laws

Re: Reaction Steps

Re: Half-reactions

Re: E vs Eo

Re: Cell Potentials and Agents

Re: Salt Bridge Notation

Re: Dependence of Temperature

Re: T1 vs. T2

Re: Assumptions that ΔS naut and ΔH naut are constant

Re: Why do we assume the changes are constant

Re: van't hoff equation

Re: Acids and Bases

Re: chelating ligands [ENDORSED]

Re: Cell Potential at Equilibrium

Re: State Functions

Re: constant temp

Re: What is the difference between an insulated and isolated system?

Positive and Negative signs in equations

Re: enthalpy and heat units

Re: Textbook 4D.13

Re: Sign Change Enthalpy Change Product bonds Form

Re: midterm 2 [ENDORSED]

Molarity in Thermochemistry

ICE Chart

What does Kc represent?

Re: How to find my posts

Re: Kc