CHEMISTRY COMMUNITY

Dylan Do

An odes are negative so it repels the electrons. Electrons leave and therefore oxidation occurs. Cat hodes are positive so it attracts the electrons. Electrons flow toward it so reduction occurs. A fun memory trick is this pun I learned. [Cat]ions are [paw]sitive. ie. Cat ions are positive so cat h...

Dylan Do

Hi Minh-Anh! Steady state reaction means that the concentration of its intermediates are constant throughout the reaction.

Dylan Do

Why are there different forms of the arrhenius equation? (refer to images) And do I need to have the ln(k/k) one memorized?

Dylan Do

Can someone explain the relation between the wMAX and the $\Delta G$ ? Why are both of them equal = - n F E?

Dylan Do

For the shorthand notation, how do I know when to put Pt(s) in the diagram and when not to? For example, why do the equations below have Pt(s) while others do not?

Dylan Do

How do I figure out the oxidation half reaction and reduction half reaction for this?
$Pt | O_{2} | H^{+} || OH^{-} | O_{2} | Pt$

Dylan Do

Question asks:

Write the half-reactions and the balanced equation for the cell reaction for each of the following galvanic cells:

(C) $C | H_{2} | H^{+} \left | \right |Cl^{-} | Cl_{2} | Pt$

How do I approach this question?

Dylan Do

For Shorthand Notation of Anode Cathode Cells how do we know the way to order the elements on the anode and cathode side?

For example

Pb(s)|PbCl2(s)|Cl−(aq)‖Cl−(aq)|AgCl(s)|Ag(s)

Dylan Do

For those types of questions, you should use whatever temperature given to you(this temperature could be the final or the initial depending on the situation). I am not aware of any 14B questions that give multiple temperatures.

Dylan Do

Because the atoms of $P_{4}$ split into two different compounds. Some of the P atoms become the oxidizing agents while the others become the reducing agents.

Dylan Do

\Delta G and E are related in that a spontaneous reaction means \Delta G <0 and E is >0. We can connect them by saying when one is negative, the other is positive . \Delta G and K relation can also be explained by a spontaneous reaction. In a spontaneous reaction, \Delta G <0 while K>1. This also m...

Dylan Do

There are the steps for balancing a basic redox reaction. First split them into oxidation half and reduction half reactions. Then consider the change in each element's oxidation number to determine the number of e- lost/gained. Example I will use is: X^{-}+Y+\rightarrow X+Y^{3-} Oxidation: Loss of e...

Dylan Do

$E=E^{o} - \frac{RT}{nF} *lnQ$

To find Q take P(H2) and divide it by $[H^{+}]^{2}$
because P/R and it's 2H+(aq)+2e−↽−−⇀H2(g)

For this E $^{o}$ = 0

Dylan Do

You need to refer to the list of elements and their reduction potentials. Higher reduction potential(likely to reduce) means better oxidizing agent.

https://sites.google.com/site/chempendix/potentials

Dylan Do

This is a joke AND a memory trick:
[CAT]ions are [PAW]sitive!

Dylan Do

The relationship between ΔG and equilibrium is fundamental to understanding chemical reactions. At equilibrium, the forward and reverse reactions are occurring at the same rate, so there is no net change in the concentrations of the reactants and products. ΔG is related to the difference in the Gibb...

Dylan Do

Gibbs free energy is the potential energy. So when Gibbs free is negative, then the reaction has the potential to lose energy meaning it is spontaneous. The equation for standard Gibbs free energy is \Delta G^{o} = -RTlnK. K being greater than 1(Products>reactants at Eq) makes lnK positive, making G...

Dylan Do

Because adding the standard cell potentials for anodes and cathodes equal to zero.

Dylan Do

It is actually going from $Mn^{7+}$ to $Mn^{2+}$ meaning it gains electrons. How did I know that? Well...
let's say charge of Mn reactant is 'X'
Now we know the total charge of $MnO_{4}^{-}$ has to be -1.
So now use algebra to find Mn charge (X):
-1 = X + (4*-2)

Dylan Do

In order to solve for T I must first find q. How do I find the enthalpy change for this reaction?

Dylan Do

First use the ideal gas law $PV=nRT$
to find the number of moles(n). Then use $\Delta S = n*C_{V,m}*ln(\frac{T2}{T2})$

Dylan Do

To get started, use the 4.39 minutes and take the 400W to convert to Joules. (400W=400J/s). Then find the mass of content that was vaporized, and convert that into moles. Take Joules and divide by moles.

That's how to get started but let me know if you need more explanation.

Dylan Do

Can somebody explain to me the concept of a reversible reaction, and why an infinitesmal change is possible for reversing a reaction?

Dylan Do

These formulas might be helpful.
$C_{P}=C_{V}+R$
$\Delta U = nC_{V}\Delta T$

Dylan Do

You have correctly calculated the heat required to melt the ice , but that value doesnt represent q. In order to find q you must combine that value to the heat required to bring 54.2g of ice from 0 degrees C to the T_{F} . Since we do not have the \Delta T , we cannot find q like that, but we can se...

Dylan Do

Bond enthalpy is the energy associated with each individual bond in a molecule or compound. Standard Reaction Enthaply is the overall energy change for the reaction as a whole. Standard reaction enthalpy can be calculated by taking the negative values bond enthalpies for each of the products(energy ...

Dylan Do

How exactly will the midterm exam be curved?

Dylan Do

An isolated system is a system that does not intereact with its surroundings as neither matter nor energy can enter or exit it. An example could be hot water sealed tightly in a thermoflask. That way neither the water(matter) nor heat(energy) can enter or exit. In other words, it stays warm.

Dylan Do

To add on, reversible reactions are where the K constant comes into play. K represents the ratio between products:reactants at equilibrium. Only reversible reactions will have equilibrium concentrations for reactants and products.

Dylan Do

How do I go about solving part A and part B?

Dylan Do

When an acid is monoprotic it means each atom contains one and can donate one proton. When an acid is weak it means that the acid's solution will not dissociate all the way. In other words, not all the reactants will convert meaning not all the molecules will dissociate and donate. As for calculatin...

Dylan Do

Create an ICE table. To find the initial concentration(M) of ammonium carbamate([ NH_{4}(NH_{2}CO_{2}) ) take the initial mass(25.0g) and convert it to moles and divide it by the volume(0.250L). The initial concentrations of NH3 and CO2 are 0. Then for equilibrium concentration of ammonium ...

Dylan Do

What is the difference between "Workshop", "Step-up", and "Drop-in" Sessions?

Dylan Do

Here is how you would do an ICE chart after adding [NO]

Dylan Do

Open the Course Canvas page("lecture 1" or "lecture 2") and click "UCLA Media Reserves" to access lecture videos. You may also check the syllabus to see which chapters correspond with each week's lectures.

Dylan Do

The answer on the answer key is given in the form of pressure instead of concentration
( $(P_{C2H4Cl2})^{2}$ instead of just $[C2H4Cl2]^{2}$ ).
How do we know whether the expression for K should be in concentration or pressure.

CHEMISTRY COMMUNITY

Search found 36 matches

Re: Anode vs Cathode

Re: Steady State

arrhenius equation

- n F E

Galvanic Cells Shorthand Notation

Textbook Question 6L 3D

Textbook Question 6L 3B

Shorthand Notation for Anode Cathode Cells

Re: finding -pdeltav using pv=nrt

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Re: How are ΔG, E, and K related?

Re: How To Balance Redox

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Re: Post All Chemistry Jokes Here

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Re: Gibbs Free Energy Equilibrium Equation

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Re: Separating a redox reaction into two half reactions

Textbook Question 4.15

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Reversible Reactions

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Week 4 Midterm

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Chemistry Study Sessions [ENDORSED]

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