Search found 30 matches

by Rhiannon Imbeah 2I
Wed Mar 08, 2017 12:03 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalyst vs. Intermediate Species
Replies: 2
Views: 554

Catalyst vs. Intermediate Species

What is the difference between a catalyst and an intermediate species?
by Rhiannon Imbeah 2I
Wed Mar 08, 2017 12:02 am
Forum: Biological Examples
Topic: Lecture Example: Homogeneous Catalyst
Replies: 1
Views: 608

Lecture Example: Homogeneous Catalyst

In the example of the homogeneous catalyst (nitric oxide conversion), in the very last step, how was 3/2 O2(g) converted to O3(g)? Thank you!
by Rhiannon Imbeah 2I
Tue Mar 07, 2017 11:56 pm
Forum: *Electrophiles
Topic: Question Regarding Alkenes
Replies: 2
Views: 439

Question Regarding Alkenes

In regards to alkenes, it was said in lecture that in a chemical reaction the pi-bond would break rather than the sigma bond. Why is this?
by Rhiannon Imbeah 2I
Mon Mar 06, 2017 12:37 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pre-Equilibrium Approach
Replies: 1
Views: 264

Pre-Equilibrium Approach

In the Pre-Equilibrium approach is the 2nd step always the slow step?
by Rhiannon Imbeah 2I
Sun Mar 05, 2017 10:57 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Ratio of Rate Constants (Energy Barriers)
Replies: 2
Views: 327

Ratio of Rate Constants (Energy Barriers)

When looking at the reverse rate (k') of a reaction, why is a lower rate constant required for a higher energy barrier? Visa versa for forward reaction (k), why is a higher rate constant required for a lower energy barrier?
by Rhiannon Imbeah 2I
Thu Feb 23, 2017 1:41 am
Forum: First Order Reactions
Topic: Question About the 1st Order REaction Rate Law
Replies: 2
Views: 420

Question About the 1st Order REaction Rate Law

Will we ever have to use this rate law to calculate the product concentration or is it only used for reactant concentrations?
by Rhiannon Imbeah 2I
Thu Feb 23, 2017 12:25 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: Method of Initial Rates: Course Reader Question
Replies: 1
Views: 267

Method of Initial Rates: Course Reader Question

In the course under the section METHODS OF INITIAL RATES, the question was asked How does initial rate depend on the concentration of nitrogen dioxide [NO2 ? What was the answer to this question?
by Rhiannon Imbeah 2I
Sun Jan 29, 2017 9:54 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 885301

Re: Post All Chemistry Jokes Here

"Don't trust atoms, they make up everything." ;)
by Rhiannon Imbeah 2I
Sun Jan 29, 2017 9:52 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Question 8.65
Replies: 2
Views: 283

Re: Question 8.65

Yes, I had to balance it but forgot to type it in. Thank you for the clarification.
by Rhiannon Imbeah 2I
Sun Jan 22, 2017 11:27 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Question 8.65
Replies: 2
Views: 283

Question 8.65

In question 8.65 the following equations:

1) 2NO +O2 --> 2NO2
2) 2NO2 + O2 --> N2O5

With the final equation reading:

2NO + 3/2 O2 --> N2O5

Following the process it appears that 2NO2 was cancelled out of the first and second, but why is that?

Thank you for your help!
by Rhiannon Imbeah 2I
Fri Jan 13, 2017 7:45 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State Property Difference
Replies: 2
Views: 277

State Property Difference

Hi,

Can someone clarify the reason why temperature and pressure are state functions but work is not? Thank you.
by Rhiannon Imbeah 2I
Wed Jul 27, 2016 6:42 am
Forum: Naming
Topic: Naming with Ammines [ENDORSED]
Replies: 1
Views: 238

Naming with Ammines [ENDORSED]

Just a quick technical question. For example, if you had a compound with six ammines it would be hexa and ammine. Would you write the name as hexaamine or hexammine?
Thank you!
by Rhiannon Imbeah 2I
Tue Jul 26, 2016 11:46 pm
Forum: Calculating the pH of Salt Solutions
Topic: Spectator Ions?
Replies: 5
Views: 855

Re: Spectator Ions?

Thank you!
by Rhiannon Imbeah 2I
Tue Jul 26, 2016 11:35 pm
Forum: Calculating the pH of Salt Solutions
Topic: Spectator Ions?
Replies: 5
Views: 855

Re: Spectator Ions?

Oh ok. Would this also include the cations that are from groups 1 and 2 on the periodic table?
by Rhiannon Imbeah 2I
Tue Jul 26, 2016 11:16 pm
Forum: Calculating the pH of Salt Solutions
Topic: Spectator Ions?
Replies: 5
Views: 855

Spectator Ions?

In a section on salts as acids and bases, the elements Na and Cl were referred to as spectator ions? Is there a specific definition for spectator ions or is this simply a colloquial term?
Thank you.
by Rhiannon Imbeah 2I
Tue Jul 26, 2016 11:09 pm
Forum: Calculating the pH of Salt Solutions
Topic: Finding Ka from Kw/Kb [ENDORSED]
Replies: 2
Views: 582

Re: Finding Ka from Kw/Kb [ENDORSED]

Oh yes! Thank you very much
by Rhiannon Imbeah 2I
Tue Jul 26, 2016 10:24 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Weak Acids and Bases as Buffers [ENDORSED]
Replies: 1
Views: 326

Weak Acids and Bases as Buffers [ENDORSED]

Hello,
Just a question about the concept of weak acids and bases. How can a weak acid or base act as a buffer if the do not fully dissociate? Wouldn't it suffice to use a strong acid or base?

Thank you
by Rhiannon Imbeah 2I
Tue Jul 26, 2016 7:52 pm
Forum: Calculating the pH of Salt Solutions
Topic: Finding Ka from Kw/Kb [ENDORSED]
Replies: 2
Views: 582

Finding Ka from Kw/Kb [ENDORSED]

In an example in the course reader for calculating the pH of the 0.15M NH4Cl, the given Kb for NH3 = 1.8x10^-5. There is a step that calculated an amount for Ka by dividing Kw by Kb:

Ka Kb=Kw=10^-14

Ka =Kw/Kb= 5.6x 10^-10.

I am not sure how this answer for Ka was calculated.
by Rhiannon Imbeah 2I
Tue Jul 26, 2016 4:44 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Aqueous Solutions in Equilibrium Constant
Replies: 2
Views: 824

Aqueous Solutions in Equilibrium Constant

For the following equations: NH4+ (aq) + H2O (l) ⇌ NH3 (aq) + H3O+ (aq), would only the concentration of H2O be removed or are aqueous solutions also not counted in the equilibrium constant?

The answer could either be:

K=[NH3][H3O]/[NH4]
or
K= 0


Thank you:)
by Rhiannon Imbeah 2I
Sun Jul 24, 2016 8:46 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Increasing yield without adding reactants
Replies: 3
Views: 319

Increasing yield without adding reactants

This was a question in the course and I'm not sure if we went over it in lecture:

For the reaction N2(g)+3H2(g) (--->)(<----) 2NH3(g)

How would you increase increase the yield of ammonia without adding more reactants?

Thank you.
by Rhiannon Imbeah 2I
Mon Jul 18, 2016 8:54 pm
Forum: Molarity, Solutions, Dilutions
Topic: Question About #5 on Post Module
Replies: 1
Views: 226

Question About #5 on Post Module

Hello, I am revisiting the Molarity and Dilution module. Question 5 in the post-module section is asking for the final molarity. After I finished converting the volume in mL to L, I was moving on to the molar calculations and the measurement is given in grams. Is the next step to convert the grams i...
by Rhiannon Imbeah 2I
Tue Jul 05, 2016 5:07 pm
Forum: Balancing Chemical Reactions
Topic: Calculating Net Moles
Replies: 1
Views: 335

Calculating Net Moles

In one of the post-assessment question regarding balancing chemical equation, we are asked to find the net number of moles produced. How would you go about finding the net number of moles produced in a chemical reaction? Thank you
by Rhiannon Imbeah 2I
Tue Jul 05, 2016 5:07 pm
Forum: Balancing Chemical Reactions
Topic: Calculating Net Moles
Replies: 3
Views: 732

Calculating Net Moles

In one of the post-assessment question regarding balancing chemical equation, we are asked to find the net number of moles produced. How would you go about finding the net number of moles produced in a chemical reaction? Thank you
by Rhiannon Imbeah 2I
Sat Mar 12, 2016 6:12 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Highest Priority Atom.
Replies: 2
Views: 317

Highest Priority Atom.

How do you determine which atom or atom group is the highest priority?
by Rhiannon Imbeah 2I
Wed Feb 24, 2016 3:32 pm
Forum: *Electrophiles
Topic: Thermody. and Kineticsof Organic Rxns Textbook Review
Replies: 1
Views: 249

Thermody. and Kineticsof Organic Rxns Textbook Review

I have the 5th edition chem textbook. Which chapter(s) go over the section on Thermodynamics and Kinetics of Organic reactions?
by Rhiannon Imbeah 2I
Sat Nov 07, 2015 11:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homo/Heterogenous Equilibria
Replies: 2
Views: 502

Re: Homo/Heterogenous Equilibria

In an equilibrium constant, which substances are not considered?

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