Search found 13 matches

by Yi Ying Chen 3N
Fri Mar 17, 2017 12:52 am
Forum: Balancing Redox Reactions
Topic: Q4 2013 Practice Final
Replies: 2
Views: 343

Re: Q4 2013 Practice Final

Here, "n" represents the number of electrons in the balanced half reactions. In this question, our half reactions are: (Fe \rightarrow Fe^{2+} + 2e^{-}) \times 2 <-- we multiply this one by 2 to balance out the electrons and 4e^{-} + 2H_{2}O + O_{2} \rightarrow 4OH^{-} Hope that he...
by Yi Ying Chen 3N
Mon Mar 13, 2017 12:20 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Unit of Equilibrium Constant K
Replies: 1
Views: 278

Unit of Equilibrium Constant K

Hello, I have a question regarding one of the questions in quiz 2. The question is: Consider the following reaction at equilibrium. A\rightleftharpoons B+C The equilibrium concentration were measured as follows: [A] = 0.0100M, [B] = 0.500M, [C] = 2.50M In a kinetic experiment, the rate constant of t...
by Yi Ying Chen 3N
Thu Mar 09, 2017 10:11 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1015175

Re: Post All Chemistry Jokes Here

ATTENTION! A new element has been discovered!
by Yi Ying Chen 3N
Mon Mar 06, 2017 7:06 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1015175

Re: Post All Chemistry Jokes Here

I hate dealing with triple bonds. They cause alkyne-ds of problems.
by Yi Ying Chen 3N
Sun Mar 05, 2017 4:49 pm
Forum: *Cycloalkenes
Topic: Cyclopropane
Replies: 1
Views: 222

Re: Cyclopropane

It cannot be cyclopropane, because all cycloalkanes have the general molecular formula of
Meanwhile, CH3-CH2-CH3 has 3 carbons and 8 hydrogens, so it is a propane, which follows the general formula of for alkanes.
by Yi Ying Chen 3N
Mon Feb 20, 2017 9:59 pm
Forum: General Rate Laws
Topic: Reaction Rate Units
Replies: 1
Views: 150

Re: Reaction Rate Units

No, the units for reaction rates do not change. They remain as M/sec or M/min (depending on what unit you use to measure time)
On the other hand, the units for rate constants (k) do change depending on the order of the reaction.
by Yi Ying Chen 3N
Sun Feb 19, 2017 6:46 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Activation energy and its reliance on temperature
Replies: 3
Views: 355

Re: Activation energy and its reliance on temperature

Ea and temperature are related by the Arrhenius equation:

The higher the activation energy, the stronger is the temperature dependence of the rate constant k.
by Yi Ying Chen 3N
Sat Feb 11, 2017 11:49 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation at 25 degrees? [ENDORSED]
Replies: 1
Views: 481

Re: Nernst Equation at 25 degrees? [ENDORSED]

The "2.303" comes from writing the Nernst equation in log base 10 rather than in ln:



It's sometimes more convenient to use log base 10, like when you're dealing with pH.
by Yi Ying Chen 3N
Sat Feb 11, 2017 8:22 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Midterm 2014 Winter Q5A
Replies: 2
Views: 398

Re: Midterm 2014 Winter Q5A

Yeah, I'm also getting 1.21 x 10^-22.
Perhaps there's an error in the course reader?
by Yi Ying Chen 3N
Sat Feb 04, 2017 3:04 pm
Forum: Balancing Redox Reactions
Topic: Easy way to remember when electrons are lost/gained
Replies: 4
Views: 480

Re: Easy way to remember when electrons are lost/gained

My high school chemistry teacher taught me this trick to remember that reduction takes place at the cathode and oxidation takes place at the anode.

reduction, cathode = RED CAT
anode, oxidation = AN OX
by Yi Ying Chen 3N
Sun Jan 29, 2017 1:20 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: bomb calorimeter mechanism
Replies: 1
Views: 402

Re: bomb calorimeter mechanism

A bomb calorimeter measures the heat released in a reaction. A sample is placed in the sealed metal container (the "bomb"), which is immersed in water. The bomb is ignited electrically by a fuse wire, allowing the sample inside to combust. Once combustion has begun, energy released as heat...
by Yi Ying Chen 3N
Fri Jan 20, 2017 11:34 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Piston Diagram [ENDORSED]
Replies: 1
Views: 221

Re: Piston Diagram [ENDORSED]

For that diagram, A refers to the area of the top of the cylinder (the circular part).
If you multiply that area by the distance the piston moves due to external pressure, you'd get the change in volume.
by Yi Ying Chen 3N
Mon Jan 16, 2017 7:44 pm
Forum: Phase Changes & Related Calculations
Topic: Different enthalpy of vaporizations for water
Replies: 3
Views: 267

Re: Different enthalpy of vaporizations for water

The 40.7 degrees celsius value would be used when we're dealing with water at its boiling point (100 degrees celsius), as mentioned at the bottom of pg 283. The standard reaction enthalpy only indicates that the reactants and products are in their standard state (pure form at 1 bar/atm). Since tempe...

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