Search found 32 matches

by Annika_Karody_3L
Thu Mar 10, 2016 4:12 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: pseudo equilibrium constant
Replies: 2
Views: 788

pseudo equilibrium constant

Does the pseudo equilibrium constant refer to the equilibrium constant of the transition state, or does it have to do with the rate constants of pseudo-first/second order reactions? Also, what is the significance of the pseudo equilibrium constant?
by Annika_Karody_3L
Wed Mar 09, 2016 10:58 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: how to know which reduction rxn to use (ch 14 no. 17)
Replies: 2
Views: 265

how to know which reduction rxn to use (ch 14 no. 17)

no. 17 (a). asks for the balanced half rxns at the cathode and anode for the rxn of KMnO4 + FeCl3 I looked in the back of the book for the reduction potentials of MnO4- and Fe3+ and found that MnO4- is more likely to be reduced and put that as my cathode, and used the oxidation reaction o Fe3+ as my...
by Annika_Karody_3L
Wed Mar 09, 2016 10:32 pm
Forum: Balancing Redox Reactions
Topic: Ch 14 no. 3 part d - reducing/oxidizing agent
Replies: 2
Views: 380

Ch 14 no. 3 part d - reducing/oxidizing agent

The equation given is

H2S (aq) + Cl2 (g) --->S(s) + Cl-(aq)

They ask for the reducing and oxidizing agents, and the answer key says that Cl2 serves as both. I am wondering why this is. Thanks!
by Annika_Karody_3L
Wed Mar 02, 2016 8:22 pm
Forum: *Alkanes
Topic: structures w longest chains of the same length
Replies: 1
Views: 292

structures w longest chains of the same length

I've been looking up practice naming problems and I've come across several compounds that have more than one chain that could serve as the "longest," as they are of equal length. How do we choose among these?
by Annika_Karody_3L
Sun Feb 28, 2016 11:44 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: determining priority
Replies: 1
Views: 299

determining priority

When determining the priority of a substituent with a double/triple bond, how do we figure out whether it has priority over something else? Also, how does one go about expanding these structures? Thanks in advance!
by Annika_Karody_3L
Thu Feb 18, 2016 11:31 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Ch 15 no. 101 question about intermediate species
Replies: 1
Views: 8838

Ch 15 no. 101 question about intermediate species

This problem gives the reaction mechanism as such step 1 ClO- + H2O ----> HClO + OH- (fast equil) <---- step 2 HClO + I- ----> HIO + Cl- (very slow) step 3 HIO + OH ----> IO- + H2O (fast equil) <---- Part b. asks for the rate law, which, according to the slow step is rate = k [HClO][I-] However, sin...
by Annika_Karody_3L
Mon Feb 15, 2016 12:37 am
Forum: Second Order Reactions
Topic: What graph is linear for second order reaction?
Replies: 2
Views: 817

Re: What graph is linear for second order reaction?

the reciprocal of the concentration plotted against time should be linear if it is second order
by Annika_Karody_3L
Sun Feb 07, 2016 11:16 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Ranking substances by entropy
Replies: 2
Views: 1165

Ranking substances by entropy

I am wondering what properties of a substance trump others in terms of ranking them by entropy. I know that anything an a gaseous state will have a higher entropy than something in a solid or liquid state, but if two substances are in the same state, what determines which one has a higher entropy? A...
by Annika_Karody_3L
Fri Feb 05, 2016 1:41 am
Forum: Balancing Redox Reactions
Topic: 14.17: why are only Fe and MnO4 included?
Replies: 1
Views: 390

14.17: why are only Fe and MnO4 included?

The question asks for us to write balanced half-reactions for the redox of an acidified solution of potassium permanganate and iron(II) chloride. The half-reactions in the textbook only include the reduction reactions of MnO4 and Fe(II). Why are the reactions of Cl and K not included and how do we k...
by Annika_Karody_3L
Fri Feb 05, 2016 1:29 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14. 15 c galvanic cell diagram
Replies: 1
Views: 428

14. 15 c galvanic cell diagram

the reaction for this problem is Cd (s) + 2Ni(OH)3 (s) -----> Cd(OH)2 (s) + 2Ni(OH)2 (s) the half reactions are Cd(OH)2 + 2e- -----> 2Cd (s) + 2 OH- E standard = -.81 V 2 [Ni(OH)3 (s) + e- -----> Ni(OH)2 + OH-] E standard = +.49 V The galvanic cell diagram in the answer key reads Cd (s)| Cd(OH)2 (s)...
by Annika_Karody_3L
Thu Jan 28, 2016 2:09 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Assumptions to be made when doing calorimetry calculations
Replies: 1
Views: 2268

Assumptions to be made when doing calorimetry calculations

When doing calorimetry calculations, will the reactions always take place in an aqueous surrounding and, if so, are we always supposed to assume that the constituents of the system have the same density and heat capacity of water? Also, are we always supposed to assume a perfect system (q sys = -q s...
by Annika_Karody_3L
Sun Jan 24, 2016 11:12 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Change in entropy
Replies: 1
Views: 264

Re: Change in entropy

Entropy describes the disorder of the system. Disorder can arise in positional, rotational, or vibrational forms, and these depend on the constituent atoms and structure of a molecule. A positive change in entropy indicates an increase in disorder which, as made evident by the Gibbs free energy equa...
by Annika_Karody_3L
Mon Jan 18, 2016 1:55 am
Forum: Calculating Work of Expansion
Topic: Irreversible vs reversible expansion
Replies: 3
Views: 641

Re: Irreversible vs reversible expansion

For a reversible expansion, the pressures outside and inside the system are equal at the beginning of the process. The gas then increases or decreases its volume (thus decreasing or increasing its pressure) in very small increments, allowing the outside pressure to adjust to these changes and mainta...
by Annika_Karody_3L
Sun Jan 10, 2016 5:11 pm
Forum: Calculating Work of Expansion
Topic: Work and Expansion?
Replies: 1
Views: 320

Re: Work and Expansion?

The energy generated by a system is released in its entirety as heat when the system is under constant volume because the its contents cannot expand. When the system is under constant pressure, however, its gaseous contents may expand. Some of the energy produced and released by the reaction is used...
by Annika_Karody_3L
Fri Dec 04, 2015 6:25 am
Forum: *Biological Importance of Buffer Solutions
Topic: Applying Le Chatelier's to aqueous equilibrium questions
Replies: 1
Views: 745

Applying Le Chatelier's to aqueous equilibrium questions

On the 2013 midterm, 8A parts a and b ask about the effect of the addition lactic acid and oxygen, respectively, on the concentration of HbO2- in blood. I got the correct answers ( increases and decreases, respectively,) but I justified it by le chatelier's, and the answer key justifies it by the in...
by Annika_Karody_3L
Fri Dec 04, 2015 6:02 am
Forum: Calculating the pH of Salt Solutions
Topic: Acidic coordination compounds
Replies: 2
Views: 528

Re: Acidic coordination compounds

Ok, thanks so much!
by Annika_Karody_3L
Fri Dec 04, 2015 6:00 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Relative-withdrawing capacity of atoms/compounds
Replies: 1
Views: 411

Relative-withdrawing capacity of atoms/compounds

In number 7 part b on the 2013 midterm, it asks you to rank the structures of 4 given oxoacids in terms of increasing strength. The only differences b/w the structures are the attached atoms/ molecules, which are F, Cl, H, and CH3. I answered the question under the assumption that H is less electron...
by Annika_Karody_3L
Tue Dec 01, 2015 11:10 pm
Forum: *Titrations & Titration Calculations
Topic: Henderson-Hasselbach Equation
Replies: 4
Views: 629

Re: Henderson-Hasselbach Equation

for problems when either an ice box or henderson-hasselbach can be used, how does one determine which one to use?
by Annika_Karody_3L
Sun Nov 29, 2015 12:49 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Determining relative strength of acids and bases
Replies: 2
Views: 3173

Re: Determining relative strength of acids and bases

That does, thank you! What I meant to ask in the first part of my question was whether the cation is an acid because it cannot accept any more protons, but I realize now that it is positively charged, which also indicates that it can donate and H+ and form H3O+, so I think I'm good on that one. Than...
by Annika_Karody_3L
Sun Nov 29, 2015 4:50 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Determining relative strength of acids and bases
Replies: 2
Views: 3173

Determining relative strength of acids and bases

I wanted to clarify the justification for the classification of certain compounds as weak acids or bases. Is the compound CH3NH3Cl, an acid because it cannot acquire any more protons, as made evident by its lewis structure,and would thereby donate protons in H2O? Furthermore, is it weak because it i...
by Annika_Karody_3L
Sun Nov 29, 2015 4:38 am
Forum: Calculating the pH of Salt Solutions
Topic: Acidic coordination compounds
Replies: 2
Views: 528

Acidic coordination compounds

For 65 e.) and f.), the question asks for the pH range of AlCl3 and CuCl2, respectively (i.e. ,<, >, or = 7). I remember from lecture that such compounds tend to form acids in solution, as the cations lose their anions and subsequently coordinate with H2O molecules. I was wondering, however, how one...
by Annika_Karody_3L
Thu Nov 19, 2015 11:51 pm
Forum: Lewis Structures
Topic: The "Lewisiana" Purchase Video
Replies: 4
Views: 679

Re: The "Lewisiana" Purchase Video

Our video details how to draw lewis structures based on the amount of electrons present in the molecule and formal charge. We also briefly discussed resonance
by Annika_Karody_3L
Mon Nov 16, 2015 8:14 pm
Forum: Naming
Topic: When to write (OH2) vs (H2O) and similar topics
Replies: 1
Views: 265

When to write (OH2) vs (H2O) and similar topics

When writing the formulas of coordination compounds, should we write the atom that bonds to the tm first, or should we write the normal formula? I'm asking this question in reference to the ligands that don't have isomers. For example, in some coordination complex formulas I have seen water written ...
by Annika_Karody_3L
Sun Nov 15, 2015 10:33 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Denticity of Sulfato
Replies: 1
Views: 771

Denticity of Sulfato

Since the sulfate ion has resonance, how does one determine the denticity of such a ligand?
by Annika_Karody_3L
Sun Nov 15, 2015 11:15 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework Question 11.1 (d)
Replies: 2
Views: 403

Re: Homework Question 11.1 (d)

The equilibrium value itself is the ratio of the concentration of the products over the concentration of the reactants. Therefore, in order to maintain this ratio, if concentration of reactants increases, so does that of the products. The concentrations of product and reactant are not constant at a ...
by Annika_Karody_3L
Sat Oct 31, 2015 4:18 pm
Forum: Empirical & Molecular Formulas
Topic: Which methods to use when finding empirical formulas
Replies: 2
Views: 663

Which methods to use when finding empirical formulas

I am wondering whether our method for finding empirical formulas can differ from that which is shown in the midterm answer keys because the points are assigned to the steps of the method. For empirical formula problems where we're given the mass of the sample and of each constituent atom, I divide t...
by Annika_Karody_3L
Sun Oct 25, 2015 8:34 pm
Forum: Electronegativity
Topic: Electronegativity of Cl and N
Replies: 2
Views: 598

Re: Electronegativity of Cl and N

Thank you! Does the same apply to o and cl? Because oxygen is the central atom in HClO, but as per the trend, O would be more electronegative than Cl
by Annika_Karody_3L
Sat Oct 24, 2015 2:47 pm
Forum: Electronegativity
Topic: Electronegativity of Cl and N
Replies: 2
Views: 598

Electronegativity of Cl and N

I have always thought, as per the trend, that N is more electronegative than Cl, however, Cl is listed as more electronegative than N in the chart in our text book. What is the reason for this exception to the trend?

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