Search found 19 matches

by Hue_Vo_1D
Sun Mar 19, 2017 12:50 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: The different Nernst equations
Replies: 2
Views: 443

Re: The different Nernst equations

First is used at 25 Celcius, a shortcut.

Both will yield you the same answer, but only at 298 F. At any other temp, use the second.
by Hue_Vo_1D
Sun Mar 19, 2017 10:44 am
Forum: General Rate Laws
Topic: pre equilibrium
Replies: 4
Views: 538

Re: pre equilibrium

In any reaction systems, the slow step will always determine the rate of reaction, thus the rate law. The purpose of using Pre-Equilirbrium Approach is to substitute other terms with intermediate, which is not supposed to be in the Rate Law. Suppose you have two-step reaction and the rate limiting s...
by Hue_Vo_1D
Sun Mar 19, 2017 1:41 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalyst
Replies: 16
Views: 1263

Re: Catalyst

In the Pre-Equilibrium Approach does the slow step always determine the rate law? In any reaction systems, the slow step will always determine the rate of reaction, thus the rate law. The purpose of using Pre-Equilirbrium Approach is to substitute other terms with intermediate, which is not suppose...
by Hue_Vo_1D
Fri Mar 17, 2017 3:26 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Free Energy of Activation
Replies: 1
Views: 284

Free Energy of Activation

4.36 in Organic Chem Book

Why is the standard Gibbs free energy of activation always a positive value for all reactions?
by Hue_Vo_1D
Tue Mar 07, 2017 11:23 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: lnA: does this y-intercept exist?
Replies: 1
Views: 355

Re: lnA: does this y-intercept exist?

There would be no y-intercept (i.e the line will not cross y-axis at lnA) because theoretically, it's impossible to reach the absolute zero temperature of 0K. Also, because 1/T is the x-axis, 1/0 would be undefined.
by Hue_Vo_1D
Sun Mar 05, 2017 10:08 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: adsorption?
Replies: 2
Views: 351

Re: adsorption?

In the case of adsorption, a relatively small quantity of one substance would get attached to the surface of the bulk substrate as a result of various types of interactions. In regards to materials that we have learned in this class, adsorption is the process in which reactants sit on surface of cat...
by Hue_Vo_1D
Mon Feb 20, 2017 9:58 pm
Forum: Zero Order Reactions
Topic: Zero Order Meaning
Replies: 5
Views: 625

Re: Zero Order Meaning

Rate of zero-order rxn = k Note that what we're plotting in zero-order reaction is Concentration of R vs Time , which yields a straight line with slope of m, represented by k. The reaction is independent of initial condition , so [R]-reactant concentration of that specific rxn will decrease at a con...
by Hue_Vo_1D
Sun Feb 19, 2017 7:03 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram
Replies: 11
Views: 789

Re: Cell Diagram

The format should be that: The anode always goes on the left and cathode on the right . Separate changes in phase by | and indicate the the salt bridge with || . Other important notes: Add "Pt(s)"-Platinum, which an inert conductor that must be in the cell with the half reaction that has o...
by Hue_Vo_1D
Sat Feb 11, 2017 11:09 am
Forum: General Science Questions
Topic: Sig Figs: Rounding Off
Replies: 2
Views: 401

Sig Figs: Rounding Off

If the problem has several calculation steps, should we round off at every step before moving to the next or leave it off until the end to round just the final answer?
by Hue_Vo_1D
Sun Feb 05, 2017 9:06 pm
Forum: Balancing Redox Reactions
Topic: Intensive property
Replies: 4
Views: 406

Re: Intensive property

The unit Volt might make you confused. 1Volt=1Joule/Coulomb->similar to other intensive value such as density (g/mL). Standard reduction potential is a fixed value. Note: this means that if you multiply the half reaction by a constant, you don't multiply E° by the same constant since E° is an intens...
by Hue_Vo_1D
Mon Jan 30, 2017 2:05 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13713

Re: Quiz 1 Preparation Answers

Can someone please explain why on #5 the answer has 2NH3 on the product side? When I did the question and canceled everything, I divided 2NH3 by 2 so that it would be the same as in the target equation N2H4 + H2 = NH3. This gave me an enthalpy of -105.1kJ/mol, instead of -151 kJ/mol. Thanks I don't...
by Hue_Vo_1D
Sun Jan 29, 2017 5:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13713

Re: Quiz 1 Preparation Answers

-Write out the equation for the combustion of propane and make sure to balance the eqn. -From the given standard enthalpy of combustion (kJ/mol), figure out how many moles of propane is burned in order to release 2580. kJ of heat.(use stoichiometry). -Convert moles to mass using MM. Just let me kno...
by Hue_Vo_1D
Sun Jan 29, 2017 5:14 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13713

Re: Quiz 1 Preparation Answers

Can someone show me the setup for #6? Please and thank you! -Write out the equation for the combustion of propane and make sure to balance the eqn. -From the given standard enthalpy of combustion (kJ/mol), figure out how many moles of propane is burned in order to release 2580. kJ of heat.(use stoi...
by Hue_Vo_1D
Sun Jan 29, 2017 4:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13713

Re: Quiz 1 Preparation Answers

BrianaBarr2A wrote:For number 6, I'm a little stuck on which equation to use. Could someone help me with this?


Use the equation for the combustion of propane.
C3H8 + 5O2 => 3CO2 + 4H2O (balanced)
by Hue_Vo_1D
Sun Jan 29, 2017 4:53 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13713

Re: Quiz 1 Preparation Answers

Can someone show me the setup for #6? Please and thank you! -Write out the equation for the combustion of propane and make sure to balance the eqn. -From the given standard enthalpy of combustion (kJ/mol), figure out how many moles of propane is burned in order to release 2580. kJ of heat.(use stoi...
by Hue_Vo_1D
Sun Jan 29, 2017 3:39 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13713

Re: Quiz 1 Preparation Answers

In an isolated system, neither matter nor energy is exchanged with the surroundings->no change in internal energy->deltaU=0

Got it! Thank you.
by Hue_Vo_1D
Sat Jan 21, 2017 11:49 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework 8.25
Replies: 5
Views: 2402

Re: Homework 8.25

From what we are given, the reaction in the calorimeter releases 3.50 kJ of heat, which resulting in a temperature rise of 7.32 C in the calorimeter . The first step in solving this is -3.50kJ/7.32 C, which gives us .478 kJ/C; this is the heat capacity of this one specific calorimeter that is used i...
by Hue_Vo_1D
Wed Jan 18, 2017 12:25 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Homework 8.29: Need Clarification [ENDORSED]
Replies: 3
Views: 509

Re: Homework 8.29: Need Clarification [ENDORSED]

Generally, the main concept of this question is that the heat capacity increases with molecular complexity

-As more atoms are present in the molecule, there are more possible bond vibrations that can absorb added energy-(NO2 has one more oxygen atom compared to NO)
by Hue_Vo_1D
Sat Jan 14, 2017 11:18 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity
Replies: 3
Views: 424

Re: Heat Capacity

This is briefly explained in the book (reference page-269). Heat capacity, heat divided by change in temperature, itself is an extensive property, meaning that the larger the sample, the more heat is required to to raise its temperature by a given amount. It is, in a way, "uncertain" as th...

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