CHEMISTRY COMMUNITY

Ethan Baurle 1A

For number 9 part d do we have all the information we need to solve the problem? I'm assuming we will have to solve for the standard cell potential and find the difference between that and this new cell potential, I just don't know how to get there.

Ethan Baurle 1A

Number 8 asks for the enthalpy change per mol so wouldn't you have to convert 2000g to moles of BaSo4 and then solve per mol?

Ethan Baurle 1A

Given a rate law we could identify the slow step out of a list of steps because we know that it is the rate determining step so the law will be based ooff of its reactants.

Ethan Baurle 1A

For this particular question, you are using ones where concentrations aren't all constant because on of the reactants is zero order and does not effect the rate law. As far as dividing things goes, that is just to show the ratio of the concentration in one reaction to that of another and then compar...

Ethan Baurle 1A

Most of the time when you are working with integrated rate laws it will be because a reaction happened over a specific amount of time with an initial and final concentration. You will be asked to solve for one of the variables given the others and will use the integrated rate law to solve for this c...

Ethan Baurle 1A

Think of it like a battery being used up. After all of the reactants have gone to products, there is no more ability for it to create energy from the reaction.

Ethan Baurle 1A

Find the individual orders of each reaction based on how the rate changes with additional initial concentration of the reactants. Each reactant will have its own individual order and then you will take the sum of the orders of the reactants to find the overall order of the reaction.

Ethan Baurle 1A

When thinking about the unique vs individual rate, I look at what Dr. Lavelle went over in class with one over the coefficient times the rate of change. Each species will have the same unique rate (one over coefficient times individual rate) but different individual rates if they have different coef...

Ethan Baurle 1A

Also, don't forget that adding hydronium ions adds electrons to that side when you are balancing the electrons later.

Ethan Baurle 1A

It depends whether it is the cathode or the anode. You write the reactant first and then the product, so you would have to determine if it is the oxidation or reduction half reaction to determine the order.

Ethan Baurle 1A

I always start with balancing with H20 and then move on to OH- or H+. Makes it easier for me. The one that you use depends on the type of solution you are in, and balance other parts of the reaction before you start adding hydrogens and oxygens.

Ethan Baurle 1A

Sometimes, if given enough values, you may have the use the equation PV=nRT to solve for temperature.

Ethan Baurle 1A

Gibbs free energy is the energy free to do work. At equilibrium, no net energy is being gained or lost (nothing is really changing). Thus, at equilibrium, Delta G is 0.

Ethan Baurle 1A

A positive cell potential means spontaneous, a negative cell potential means not spontaneous. Think of the equation Delta G = -nFE. Negative delta G is spontaneous, and n (electrons transferred) and F (Faraday's constant) are always positive. Thus the, the sign of E (cell potential) determines wheth...

Ethan Baurle 1A

No. You just pick one of the values and use it to solve for the change in entropy.

Ethan Baurle 1A

Isochoric is constant volume, Isobaric is constant pressure, Isothermal is constant temperature. I don't think we have done any work with Isometric.

Ethan Baurle 1A

Balance your equation first and then omit the ones that are solids are liquids.

Ethan Baurle 1A

You can solve for temp using PV=nRT. I keep getting a wack answer for this question, however. I'm assuming the overall delta U and delta S will be zero because they are state functions, but I am not getting the right q and w quantities. Can someone who feels confident put down their values so I can ...

Ethan Baurle 1A

Think of the heat capacity as the amount of heat something can absorb. The larger the value, the more heat it will be able to absorb before it transitions to the next phase. If it can absorb more heat,it will take longer for this process to happen and will thus have a less steep slope.

Ethan Baurle 1A

Most calorimeters we work with should be isolated or closed systems. I don't think any of them will be open.

Ethan Baurle 1A

Homework problems as well as watching youtube videos on certain concepts has worked well for me. Professor Dave Explains on youtube has some good videos that explains concepts pretty clearly.

Ethan Baurle 1A

I believe the kinetic portion has to do with the movement in all direction of a molecule of a substance and the potential portion has to do with the energy that held inside the bonds of that substance.

Ethan Baurle 1A

Basically, a change in, say, 10 degrees celsius is the same as a change in 10 Kelvin. So when you're using a value for change in temperature in the equation you can use celsius and Kelvin interchangeably.

Ethan Baurle 1A

If we need to use that combustion reaction to solve for the enthalpy of a different net reaction, that value will be given to us. If we are asked to actually find the enthalpy of the combustion reaction we can use any of the methods to solve for enthalpy we learned in lecture. Either way, some value...

Ethan Baurle 1A

Anytime we are given a Ka or Kb, the acid or base is almost certainly going to be weak. This is because the Ka or Kb of a strong acid or base is extremely high because the substance gets basically completely deprotonated/protonated. This should help you in identifying weak substances right away, and...

Ethan Baurle 1A

Just for future reference and ease on test problems, any time the constant value is lower than 1 x 10^-3 it should be safe to use an approximation. You can use the % deprotonation rule to check afterwards if you are worried, but this will save you some time on exams.

Ethan Baurle 1A

I believe it is any value higher than 1 x 10^-7 that will make a difference in the PH.

Ethan Baurle 1A

Because the equilibrium constant of the decomposition of Cl2 is less than that of the decomposition reaction for F2, there are less products in the chlorine reaction than the fluorine reaction. This shows that the chlorine is more likely to keep its original form and not decompose as much, showing i...

Ethan Baurle 1A

Also, in regards to the strengths of acids and bases based on their equilibrium constants, a lower Kx (Ka or Kb) shows a weaker substance. A lower Kx also responds to a higher PKx if those are the values you are looking at, so a higher PKx would be weaker.

Ethan Baurle 1A

The higher the equilibrium constant is, the more the reaction favors the products and thus the more the compound is dissociated if it is reacting with water. This would represent a higher solubility.

Ethan Baurle 1A

When you have a reaction that consists of only gasses, you use their partial pressures in the equation that we learned to find the Kp value. When the reaction consists of compounds in a non gas state (for instance aqueous) you would plug in the concentrations of the products and reactants into the s...

Ethan Baurle 1A

This is because there is no change in the composition of the solution from flask 3 to 4. To simplify things, look at the number of ions stuck together and those floating around freely. As the pictures progress, more ions are floating around freely, but in flask 3 and 4 there are the same number of d...

Ethan Baurle 1A

K is the value of the concentrations of the products over the reactants at equilibrium, thus we would only ever use equilibrium concentrations to find K. Any other concentrations we are given at a particular point in the reaction should be put into the same equation we have been practicing in class....

CHEMISTRY COMMUNITY

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Re: LYNDON'S PORK RAMEN REVIEW

Re: Review Session-Thermo-files- Wednesday-Q11-clarification [ENDORSED]

Re: Slow Step

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