Search found 24 matches

by Miya McLaughlin 2B
Wed Mar 15, 2017 7:39 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Two Step Reactions
Replies: 3
Views: 469

Re: Two Step Reactions

Yes, it will take more energy for the slow step to be carried out compared the fast step because there is a higher energy barrier that the atoms must overcome. (ie higher activation energy) A higher activation energy means not as many molecules will be able to get over the energy barrier as often. S...
by Miya McLaughlin 2B
Mon Mar 13, 2017 4:16 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell potential equals zero?
Replies: 1
Views: 592

Re: Cell potential equals zero?

A concentration cell is when a galvanic or voltaic cell is made using the same components but at different concentrations. For example, one side of the cell could have Cu + ions with a concentration of 0.1 M while the other side has a concentration of 1 M. Because both sides have Cu+ ions, both the ...
by Miya McLaughlin 2B
Fri Mar 10, 2017 10:53 am
Forum: *Alkanes
Topic: Arranging substituents while naming
Replies: 2
Views: 294

Re: Arranging substituents while naming

No, those prefixes don't count when putting them in alphabetical order. (Example: Etheyl would be listed before dimethyl)
by Miya McLaughlin 2B
Wed Mar 01, 2017 3:55 pm
Forum: *Alkanes
Topic: Number in front of name
Replies: 2
Views: 336

Re: Number in front of name

The name will tell you where the substituent is located. In the name, the number before the substituent will indicate which carbon it is attached to. If you are instead given a picture, the substituent will be the line or series of lines protruding from one of the carbons in the chain. If you are as...
by Miya McLaughlin 2B
Mon Feb 27, 2017 4:06 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Determining Where Hydrogen Bonds
Replies: 5
Views: 605

Re: Determining Where Hydrogen Bonds

The arrow doesn't necessarily mean a bond is being broken, it just indicates where the electrons are coming from and where they end up. It's just easy for the electrons to come from bonds because they are more exposed than the electrons within the shells, thus they are easier to remove. The explanat...
by Miya McLaughlin 2B
Wed Feb 22, 2017 5:22 pm
Forum: *Electrophiles
Topic: Chapter 4 of the book
Replies: 1
Views: 297

Re: Chapter 4 of the book

The homework problems are listed at the end of each chapter in the organic chem textbook. They are pretty hard to find because the entire book is black and white, which makes all the pages look the same. The problems for Thermodynamics and organic chem are right after chapter 4. There should be a pa...
by Miya McLaughlin 2B
Wed Feb 22, 2017 5:14 pm
Forum: *Electrophilic Addition
Topic: intermediate
Replies: 2
Views: 366

Re: intermediate

An intermediate is any substance that is created in one step(product) then used up in another. If you were to add the step reactions together the intermediates would cancel out. Here is a visual example from the text book. Step 1 AC + B --> AB + C Step 2 AC + AB --> A 2 B +C In the first step, AB is...
by Miya McLaughlin 2B
Fri Feb 17, 2017 4:14 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Confusion about intermediates
Replies: 4
Views: 386

Re: Confusion about intermediates

Yes. When you add the equations together, all the intermediates should cancel out. Intermediates won't be in the final equation that represents the overall reaction.
by Miya McLaughlin 2B
Thu Feb 09, 2017 2:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.17 (HW problem)
Replies: 1
Views: 230

Re: 14.17 (HW problem)

You would need to use the half reaction that looks like this: Fe 3+ + e - --> Fe 2+ This is the only half reaction in which Fe is an ion on both sides. The other ones include Fe(s) in it's solid form. In the question, iron(II) chloride is your only source of iron and it can only give off Fe ions, no...
by Miya McLaughlin 2B
Tue Feb 07, 2017 12:24 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calculating pH
Replies: 3
Views: 369

Re: Calculating pH

I made a mistake when writing ln. [Cl-] should be squared.

ln( [H+]2 [Cl-]2 / [H2] )
by Miya McLaughlin 2B
Tue Feb 07, 2017 12:21 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calculating pH
Replies: 3
Views: 369

Re: Calculating pH

It's helpful to look at the nernst equation like this: E cell = E - (RT/nF) ln([P]/[R]) Here is an example, from the homework: H 2 (g) + Hg 2 Cl 2 (s) --> 2H + (aq) + 2Cl - (aq) For this equation, the value you'd be taking the ln of would look like this ln( [H + ] 2 [Cl - ] / [H 2 ] ) To find the pH...
by Miya McLaughlin 2B
Sat Feb 04, 2017 1:26 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation [ENDORSED]
Replies: 4
Views: 486

Re: Nernst Equation [ENDORSED]

The 0.0592 comes from combining all the constants in the equations. It represents RT/F, which is the gas constant multiplied by the temperature (in this case it's the standard temp of 273 K), then it is divided by one Faraday(F) which is 96485 C/mol. The n remains a variable because it depends on th...
by Miya McLaughlin 2B
Thu Feb 02, 2017 4:45 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Calculating the Potential of Half Reactions
Replies: 1
Views: 166

Calculating the Potential of Half Reactions

In problem 14.27 of the homework it asks you to calculate the standard potential for the half reaction: U 4+ (aq) + 4e - --> U(s) I tried adding the two half reactions from Appendix 2B that also included U to get this equation. Then I added together the E values of each equation and ended with E=-2....
by Miya McLaughlin 2B
Tue Jan 24, 2017 3:04 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Number 57 in Chapter 8 Homework
Replies: 2
Views: 286

Re: Number 57 in Chapter 8 Homework

The delta H values given in the problem are the reaction enthalpies for combustion(enthalpy of combustion is denoted by a little c subscript). You can write the three combustion reactions for each compound and use those equations for Hess' Law. For a combustion reaction, an organic compound reacts w...
by Miya McLaughlin 2B
Thu Jan 19, 2017 2:12 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: What does a Standard Enthalpy with a subscript "c" mean?
Replies: 2
Views: 933

Re: What does a Standard Enthalpy with a subscript "c" mean?

The subscript "c" on the delta H denotes that it's the Standard Enthalpy value for a combustion reaction. A combustion reaction is when a compound burns completely with O2 gas to create CO2 and H2O. Here is an example. Ex: 2 C2H2(g) + 5 O2(g) --> 4 CO2(g) + 2 H2O(g) It's not the exact oppo...
by Miya McLaughlin 2B
Sat Jan 14, 2017 2:07 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Measuring Heat Transfer (extensive vs intensive)
Replies: 2
Views: 274

Re: Measuring Heat Transfer (extensive vs intensive)

Extensive Properties are physical properties that depend on the size of the sample you are using. Intensive Properties are physical properties that DO NOT depend on the size of the sample. Example: Say you have a sample of water. The volume(a physical property) of that sample will be dependent on ho...
by Miya McLaughlin 2B
Wed Nov 16, 2016 3:42 pm
Forum: Lewis Acids & Bases
Topic: Homework 12.9 [ENDORSED]
Replies: 5
Views: 708

Homework 12.9 [ENDORSED]

For this problem, it asks if a set of equations can be classified as reactions between Bronsted acids and bases. I know that means a proton must be transferred from one molecule to another. However, with the reactions they gave us, I don't know how to tell if a proton is transferred in that way? The...
by Miya McLaughlin 2B
Tue Nov 01, 2016 8:07 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Molecular Orbitals between Two Atoms that are Different Elements
Replies: 1
Views: 300

Re: Molecular Orbitals between Two Atoms that are Different Elements

The anti-bonding orbitals have a higher energy because they are less stable than the bonding orbitals. This is because they are farther away from the nuclei of the atoms. Stability = lower energy. This higher energy level, means anti-bonding orbitals are closer in energy to the less electronegative ...
by Miya McLaughlin 2B
Mon Oct 31, 2016 6:11 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7569
Views: 1011570

Re: Post All Chemistry Jokes Here

Heisenberg is driving down the road when a cop pulls him over and asks him, "Do you know how fast you were going back there?"
To which Heisenberg responds, "No, but I know where I was."
by Miya McLaughlin 2B
Sun Oct 30, 2016 10:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles
Replies: 1
Views: 218

Re: bond angles

The bond angles for a see-saw shape are 90 degrees, 180 degrees and 120 degrees. T-shaped is 90 and 180. Square-pyramidal is 90. Square planar is also 90. A good way to figure out the bond angles is to look first look at how many regions of electron density there are. Take the see-saw shape for exam...
by Miya McLaughlin 2B
Mon Oct 17, 2016 7:21 pm
Forum: Resonance Structures
Topic: Homework 3.71 [ENDORSED]
Replies: 1
Views: 242

Homework 3.71 [ENDORSED]

For this problem in the text book, it asks you to select the Lewis structure that is "likely to make the dominant contribution to a resonance hybrid."

What does it mean by "resonance hybrid" and how do you determine if it makes a contribution?
by Miya McLaughlin 2B
Mon Oct 17, 2016 7:13 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formulas from Compounds [ENDORSED]
Replies: 3
Views: 505

Re: Empirical Formulas from Compounds [ENDORSED]

This makes a lot more sense! Thank you so much for your help. I understand now how to solve for the separate elements.
by Miya McLaughlin 2B
Sat Oct 08, 2016 12:16 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formulas from Compounds [ENDORSED]
Replies: 3
Views: 505

Empirical Formulas from Compounds [ENDORSED]

In the workbook, there is a quiz prep question that reads, "6.40 g of a compound was burned in air and produced 8.80 g of CO2 and 7.20 g of H2O. Find the empirical formula of the compound." I understand how to solve these problems when the mass of each element is given separately(i.e. 6.0 ...
by Miya McLaughlin 2B
Fri Sep 30, 2016 3:56 pm
Forum: Properties of Light
Topic: Question 1.11
Replies: 2
Views: 306

Re: Question 1.11

I believe "principal quantum number" is referring to the energy levels; n=1, 2, . . . etc. According to the textbook, each of the series(Balmer, Lyman, etc.) correspond to a certain final value of n. For example, when an electron jumps down from n=3 to n=2, the line of radiation given off ...

Go to advanced search