CHEMISTRY COMMUNITY

Simmi Diwanji 2B

Thank you!

Simmi Diwanji 2B

Thank you Lyndon!

Simmi Diwanji 2B

Thank you!

Simmi Diwanji 2B

It will definitely be cumulative, but I think it will focus more on thermodynamics, thermochemistry, and kinetics.

Simmi Diwanji 2B

Can someone clarify what microscopic reversibility is and its correlation to reaction mechanisms? I remember Professor Lavelle mentioning this in class but I wasn't quite sure what he meant.

Simmi Diwanji 2B

Why is there always an inverse relationship between half life and the rate constant k?

Simmi Diwanji 2B

Pt(s) is an inert electrode, meaning it helps with either reduction or oxidation without actually being changed in the reaction. It must be included in the cell diagram when an solid metal is not present on either the anode or cathode side. It aids in either the reduction or oxidation of aqueous ions.

Simmi Diwanji 2B

For what kinds of problems do you use the van't hoff equation and how do you apply it?

Simmi Diwanji 2B

For those kinds of problems, start by writing out each of the half reactions, even if one element is duplicated by appearing in both half reactions. Then, balance as usual and add the two half reactions together once the electrons can cancel. At the end, make sure to neutralize any excess H+ you may...

Simmi Diwanji 2B

The entropy of a liquid is always going to be more than a solid because there is more random movement of particles, so to find the entropy of fusion (going from solid to liquid), you would need to subtract the entropy of solid from the entropy of liquid.

Simmi Diwanji 2B

When a system is thermodynamically favorable, it means that it has -deltaG because that indicates a spontaneous reaction is occurring. In this case, it is melting.

Simmi Diwanji 2B

They are generally the same, but E(nought) is just the cell potential at standard conditions.

Simmi Diwanji 2B

Does reducing power mean the same as reducing agent or the ability of an element to be reduced?

Simmi Diwanji 2B

Zero work and no work mean the same thing. This happens when there is no change in number of moles from the reactant to product because that means no change in volume therefore no work done on the system or by the system.

Simmi Diwanji 2B

I think it might be because they don't specify if it's a monoatomic or diatomic ideal gas? I know it says nitrogen gas which is diatomic, but maybe they just don't want you to assume so you use R?

Simmi Diwanji 2B

When calculating entropy of vaporization, for example, why do you have to add the entropy of the system cooling down? I thought it would just be the entropy of the system heating up and then its entropy of vaporization at that temperature.

Simmi Diwanji 2B

Does anyone remember the explanation for why in the equation: Utotal = 3/2 nRT there is a 3/2 coefficient?

Simmi Diwanji 2B

A bomb calorimeter is an example of an isolated system, which means that no matter or energy can be transferred in or out of it. This is ideal for experiments where you would like to measure a temperature difference under constant volume where you don't have to worry about heat being transferred fro...

Simmi Diwanji 2B

A state function just refers to a property that is independent of the path it takes to get to that value. For example, the length of a hike up a mountain is dependent on the path you take, so it is a path function, whereas the altitude is the same regardless, so it is a state function.

Simmi Diwanji 2B

I believe they are the same thing. Bond enthalpy/energy is the energy required to break one mole of a bond.

Simmi Diwanji 2B

No, a higher bond energy means that there is a higher potential E meaning lower stability as the bond has more potential to change. Low bond energy equates to lower potential chemical energy therefore higher stability in the bond. In regard to molecules with resonance structures, they should have a ...

Simmi Diwanji 2B

A reversible process is always in equilibrium and always does more work than an irreversible process. An irreversible expansion means that there will be an entropy change in the system.

Simmi Diwanji 2B

I think enthalpy could be either kJ or kJ/mol but the standard enthalpy of formation always must be kJ/mol.

Simmi Diwanji 2B

A state property is a value determined by its current state and is independent of the path taken to obtain that state. State properties can be added and subtracted. An example of one is enthalpy.

Simmi Diwanji 2B

Even if there is a decrease in internal energy, when solving for work or heat in U = q + w, do you always assume change in U is positive?

Simmi Diwanji 2B

I think it's just important that you understand how to formulate the chemical equations for buffers, namely what kind of products a group of reactants can yield, like Professor Lavelle mentioned in lecture for the first test.

Simmi Diwanji 2B

The equilibrium arrows should be used for all reactions in equilibrium, no matter if it is a strong or weak acid or base. However, if the reaction favors one side, the products or the reactants, than the lengths of the arrows become skewed in the respective directions.

Simmi Diwanji 2B

It should specify, but you should do what makes sense. Aqueous solutions will have concentrations so you should find Kc while gases will probably have partial pressures (but it could also be concentration) so you should find Kp.

Simmi Diwanji 2B

The significance of Q<K and vice versa is that it helps determine whether a reaction has reached equilibrium at a certain point in time. If it hasn't reached equilibrium (Q=K), than that means that the reaction will either favor the reactants or products in order to proceed towards equilibrium.

Simmi Diwanji 2B

Here's an example: HCl + NaOH --> NaCl +H2O In this reaction, HCl is the acid and NaOH is the base. Since the HCl donates a proton it is the acid and since the OH- accepts the proton it is the base. NaCl would be the conjugate base and would be a acid-conjugate base pair with HCl. H2O would be the c...

Simmi Diwanji 2B

Q is very similar to K in that they are calculated the same way, but Q calculates the ratio of products/reactants at any given time, usually at initial concentrations or partial pressures. It is used to compare a reaction to its equilibrium constant K to see what side the reaction favors.

Simmi Diwanji 2B

Can someone explain how to do problem 5I.13 part b) from the textbook?

CHEMISTRY COMMUNITY

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Re: Hotdog #5

Re: LYNDON'S PORK RAMEN REVIEW

Re: DOWNLOAD SESSION WORKSHEETS HERE - Sun 7-9PM (Karen)

Re: Final

Microscopic reversibility

Half Life and k

Re: Pt inert electrode

Temperature and Gibbs

Re: Homework 6th edition, 14.5, part d

Re: Entropy of Fusion

Re: Melting/Spontaneous Processes

Re: E^o(cell) vs. Ecell

Reducing power

Re: 0 work vs no work

Re: Problem 4F.11 7th Edition

Entropy Calculations

Ideal Gas Internal Energy

Re: Bomb Calorimeter

Re: State Function

Re: Bond enthalpy vs Bond Enregy

Re: Total bond energy

Re: Irreversible vs. Reversible Expansion

Re: Enthalpy Units

Re: 8.55

Internal Energy

Re: buffer questions on test

Re: Equilibrium Arrow

Re: Concentration or Partial Pressure

Re: Understanding Q

Re: Cojugate Acids and Bases

Re: K vs. Q

5I.13