CHEMISTRY COMMUNITY

Eric Quach 1C

Is there a difference in using a platinum electrode or a graphite (carbon) one?

Eric Quach 1C

Can someone explain what the A is in the Arrhenius Equation and why it's there?

Eric Quach 1C

Does molecularity only depend on the reactants? If there are multiple products does that affect molecularity?

Eric Quach 1C

Out of curiosity, what is the integrated rate law for a third order reaction?

Eric Quach 1C

Considering that it would make all of our answers have one sig fig, we would probably use the number that has next least number of sig figs. Also, we know the exact value for n, so it has "unlimited" sig figs in a sense.

Eric Quach 1C

AB would be an intermediate because if you sum up the elementary reactions for the overall reaction, AB is neither a product or reactant as it cancels out.

Eric Quach 1C

Another way to put it would be that there is a bottleneck at the slow step. For example if there are 3 steps in a reaction and step 2 is the slow step, it doesn't matter if step 1 and 3 are almost instantaneous as step 2 must finish occurring before step 3 which completes the reaction.

Eric Quach 1C

k is the rate constant and is different for each reaction. the units for k vary depending on the order of the reaction. k can be found experimentally, but on the tests we will probably have to calculate it or solve for it.

Eric Quach 1C

Adding on to the answers, to find the order one must plot the ln A, one over A, and just A (A being concentration of a reactant) against time to determine if it is first, second, or zero order. For the overall order, add the orders of each reactant to get the order for the entire reaction.

Eric Quach 1C

How are reduction potentials calculated?

Eric Quach 1C

I know that salt bridges are used to balance the charges to maintain the charges, but how exactly does a salt bridge do this?

Eric Quach 1C

we don't have to memorize the oxidation states of metals, as they change depending on the compound. Just make sure to memorize the states for oxygen, the halogens, groups 1 and 2 and with that you can figure out the oxidation states of the metals.

Eric Quach 1C

when its kp, the only thing to make sure about units is that they are all in units of pressure and the same unit of pressure. The units all cancel out in the end, making kp not have a unit.

Eric Quach 1C

as work is equal to -PdeltaV and there is no change in volume, the expression would equal zero and no work is done.

Eric Quach 1C

the two moles of water are not part of the ice table or the equilibrium constant as water is a liquid. This means that the water is solvent and there's an excess of it.

Eric Quach 1C

Yep if work is done by the system to the surrounding then the work is negative. If work is done by the surroundings on the system then work is positive. It's similar to q where if heat is released to the surroundings then q is negative. However, if the system gains heat, then q is positive.

Eric Quach 1C

I think we just need to know how to apply it. The integral was used to help explain how the formula w=-PdeltaV was derived.

Eric Quach 1C

The units commonly used for entropy is J/K but I don't quite understand why it's like that. Is the unit supposed to show change in energy per kelvin?

Eric Quach 1C

use the conversion 1L*atm=101.33 J and use dimensional analysis to convert

Eric Quach 1C

Yep the formulas give the same answer. I think Dr.Lavelle was just using the integral to show how the P delta V formula was derived.

Eric Quach 1C

If a piston is compressing then is work being done to the system or is the system doing work on the surrounding? What does this mean for negative and positive values of work?

Eric Quach 1C

Is the change in enthalpy from water as a liquid to gas positive and negative? Why?

Eric Quach 1C

Reversible reactions have a two way arrow in a chemical reaction, while irreversible ones will have a one-way arrow.

Eric Quach 1C

State of matter does affect enthalpy. The value of enthalpy between liquid water and vapor will be different.

Eric Quach 1C

K is the equilibrium constant and represents the ratio of products to reactants at equilibrium. While Q is the reaction quotient and is the ratio of products to reactants at a certain point in time (can be before or at equilibrium). Remember if Q does not equal K that means the reaction is not at eq...

Eric Quach 1C

To find pH simply take the -log{H30+}.

Eric Quach 1C

Typically, Kp is used for when they give you partial pressures which means it will typically be used with problems that contain gases in the products or reactants. Kc is used with concentration values and are typically used in problems with aqueous solutions. However, if a problem gives you the conc...

Eric Quach 1C

The value of R used is dependent upon the unit of pressure used.
For example if atmosphere is the unit of pressure used then 0.08206 is the R value. However, if torr is the unit of pressure used then use the R value of 62.36.

Eric Quach 1C

What does it mean when K is larger than 1 and smaller than 1?

Eric Quach 1C

For the equilibrium constant K, how does changing the coefficients in the chemical reaction affect K?
For example, how does doubling each coefficient change the value of K?

CHEMISTRY COMMUNITY

Search found 30 matches

Cell Diagram

Arrhenius Equation

Molecularity

Third Order Reactions

Re: n and significant figures

Re: Reaction Intermediates

Re: Slow Step

Re: k values

Re: Order of a Reaction

Reduction Potentials

Salt Bridge

Re: Oxidation States

Re: Kp equilibrium constant

Re: Work without change in volume

Re: Liquid and moles

Re: Work

Re: Integral Expression for Work

Units for Entropy

Re: Work by expansion

Re: finding W

Compression Work

Change in Enthalpy

Re: Reversible and Irreversible Process

Re: Enthalpy and States

Re: Concentration

Re: pH

Re: Using Kc or Kp

Re: ideal gas constant

Value of K

Equilibrium Constants