Search found 26 matches

by Rachel McMillan 3A
Fri Mar 11, 2016 8:01 pm
Forum: *Alkanes
Topic: Naming compounds with cyclo substituents
Replies: 1
Views: 321

Naming compounds with cyclo substituents

On Quiz #3, I was wondering how the following compound would be named (picture attached):
Thank you!
by Rachel McMillan 3A
Fri Mar 11, 2016 7:35 pm
Forum: First Order Reactions
Topic: Calculating concentration #23c
Replies: 4
Views: 903

Re: Calculating concentration #23c

chapter 15- Chemical Kinetics
by Rachel McMillan 3A
Fri Mar 11, 2016 4:01 pm
Forum: First Order Reactions
Topic: Calculating concentration #23c
Replies: 4
Views: 903

Calculating concentration #23c

In problems 25c I encountered a problem In 23 part c, the question asks us to determine the rate constant for the first order reaction for the equation 2A->B+C given that [A0]=.153, and that after 115 sec the concentration of B rises to .034 M. I tried to calculate the concentration of A by multiply...
by Rachel McMillan 3A
Wed Mar 09, 2016 4:52 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Calculating q
Replies: 1
Views: 474

Calculating q

I was going through problems in Ch8, and I am confused as to when I should use q=nCdeltaT and q=CdeltaT? Could somebody please clarify this? Thank you :)
by Rachel McMillan 3A
Mon Feb 29, 2016 1:32 pm
Forum: *Alkanes
Topic: Quiz #3 Prep #5 priority on alkanes??
Replies: 1
Views: 336

Quiz #3 Prep #5 priority on alkanes??

For number 5 on the first Quiz #3 prep, I understand why 1 is assigned to iodo (because it is the bigger atom so it has priority), but why is it 3-bromo-1-iodohexane instead of 1-iodo-3-bromohexane?
by Rachel McMillan 3A
Wed Feb 24, 2016 11:36 pm
Forum: *Alkenes
Topic: Organic Molecules naming of compounds, numbers
Replies: 1
Views: 317

Organic Molecules naming of compounds, numbers

For the lewis structure 2-Methyl-1, 3-butadiene, what does the 1 after methyl signify? This is one of the examples of an alkene on page 3 of our Organic Molecules textbook. Thank you!
by Rachel McMillan 3A
Thu Feb 18, 2016 5:46 pm
Forum: Significant Figures
Topic: When there are fractions [ENDORSED]
Replies: 3
Views: 2993

When there are fractions [ENDORSED]

In the Quiz 2 prep that we are turning in, I'm having trouble figuring out how many significant figures to use for #4. When a fraction is involved such as 1/32, do we use two or three significant figures in the answer, or do we ignore the fraction entirely and simply use the other numbers in the pro...
by Rachel McMillan 3A
Wed Feb 17, 2016 9:09 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Affect of precipitation on cell potential
Replies: 1
Views: 2178

Affect of precipitation on cell potential

For #8 part b we were asked what the effect of the precipitation of CdS was on cell potential when sodium sulfide is added to the Cd+2 half-cell. I honestly have no idea what the effect of this would be. Can anybody please help? Thanks :)
by Rachel McMillan 3A
Mon Feb 08, 2016 12:53 am
Forum: Calculating Work of Expansion
Topic: Calculating work from expansion 1st Quiz, #4
Replies: 1
Views: 346

Calculating work from expansion 1st Quiz, #4

On number four of our quiz, the problem asks what the work is when an ideal gas expands from 2.0 L to 6.0 L. The initial internal pressure is 1.00 atm. I used w=-P*deltaV, which was incorrect. Which equation should I use? Thank you :)
by Rachel McMillan 3A
Sun Feb 07, 2016 11:20 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Calculating Bond Enthalpy Quiz #1 Problem #2
Replies: 1
Views: 450

Calculating Bond Enthalpy Quiz #1 Problem #2

On our first quiz, we were asked to calculate the mean bond enthalpy of the H-F bond. Delta H was calculated to be -539 kJ, and the problem states that Hydrogen gas reacts explosively with fluorine gas. Because a bond was formed between Fluorine and Hydrogen, does -539 kJ become +539 kJ?
by Rachel McMillan 3A
Sat Feb 06, 2016 5:40 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calculating Q
Replies: 1
Views: 366

Calculating Q

In the 5th edition of our textbook, #37 asks for the value of Q and for a balanced equation. Here is the information given for part a: (a) Pt(s)|Sn4(aq), Sn2(aq)||Pb4(aq), Pb2(aq)|C(gr), E 1.33 V. I thought that I would use Nernst equation but I don't have the concentrations of the ions. What ...
by Rachel McMillan 3A
Tue Feb 02, 2016 5:15 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Calculating reaction Gibbs free Energy and n
Replies: 1
Views: 438

Calculating reaction Gibbs free Energy and n

In the 5th edition of our textbook, example 13.3 asks what the reaction Gibbs free energy is when "the potential of the Daniell cell for certain concentrations of copper and zinc ions is 1.04 V." The example then states that, "From the chemical equation for the cell reaction (reaction...
by Rachel McMillan 3A
Mon Jan 25, 2016 2:55 pm
Forum: Calculating Work of Expansion
Topic: Quiz Winter 2014 #11 Finding Final Volume
Replies: 1
Views: 402

Quiz Winter 2014 #11 Finding Final Volume

In number 11 of the Winter 2014 Quiz 1 prep, the question asks, "A system undergoes a two-step process. In step 1, it expands adiabatically from 1.00 L to 2.56 L at 1.00 atm (external pressure). In step 2, it releases 73 J of heat at 1.00 atm as it returns to the original internal energy. Find ...
by Rachel McMillan 3A
Wed Jan 20, 2016 3:57 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Homework 8.27 Reversible expansion calculations
Replies: 2
Views: 446

Homework 8.27 Reversible expansion calculations

On homework question 8.27 the question asks for us to calculate the work for two processes that began with a gas sample at 305 K, a pressure of 1.79 atm, and a volume of 4.29. In part a, we are asked to calculate the work for an irreversible expansion- I am able to do this part. However, in part b, ...
by Rachel McMillan 3A
Tue Jan 12, 2016 4:19 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Enthalpy of Physical Change self-test
Replies: 1
Views: 367

Enthalpy of Physical Change self-test

In Chapter 8.11, one of the first self-tests asks for the enthalpy of vaporization of Benzene at its boiling point. The problem states that "a sample of benzene was heated to 80 degrees Celsius, its normal boiling point. The heating was continued until 15.4 kJ had been supplied; as a result, 39...
by Rachel McMillan 3A
Wed Jan 06, 2016 12:20 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversible and Irreversible Reactions Definition
Replies: 3
Views: 964

Reversible and Irreversible Reactions Definition

I'm having difficulty understanding the significance of reversible and irreversible reactions. What is the difference between the two and why are they important? Thank you :)
by Rachel McMillan 3A
Mon Dec 07, 2015 11:56 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Molecular Orbital Theory Video
Replies: 1
Views: 3048

Molecular Orbital Theory Video

Note: Posting this now that I know how to convert files to .mov format. This video was originally posted over a week ago by my partners.

Chem 14A video %3B%29.mov [ 406.27 MiB | Viewed 3048 times ]

by Rachel McMillan 3A
Mon Dec 07, 2015 10:50 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Video: Applying Le Chatelier's Principle to Photosyntheisis
Replies: 3
Views: 3403

Re: Video: Applying Le Chatelier's Principle to Photosynthei

This is the mov version of the file

Chem 14A Problem 11.115.mov [ 108.67 MiB | Viewed 3345 times ]

by Rachel McMillan 3A
Mon Nov 16, 2015 11:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Finding K to see if products or reactants are favored
Replies: 1
Views: 328

Finding K to see if products or reactants are favored

In homework problem #23 in the 5th edition of the Chemistry Textbook, the problem asks if the products or reactants will be favored (or if they will be at equilibrium) when Q=1.0 for the equation N2(g)+O2(g) -> 2NO(g). The back of the textbook indicates that the reactants will be favored. I think th...
by Rachel McMillan 3A
Thu Nov 12, 2015 4:42 pm
Forum: Naming
Topic: Writing formulas from compounds with "bis"
Replies: 1
Views: 395

Writing formulas from compounds with "bis"

#29 in the 5th edition of our Chemistry textbook asks us to write out the formula for the coordination compound sodium bisoxalato(diaqua) ferrate (III). What does bis mean and how does it change how the formula is written out?
by Rachel McMillan 3A
Sun Nov 08, 2015 9:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs K
Replies: 4
Views: 1646

Q vs K

I am having difficulty understanding the concept of Q, the reaction Quotient. What is Q and why is it significant when we consider K?
by Rachel McMillan 3A
Tue Oct 20, 2015 5:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Strengths of Repulsions
Replies: 3
Views: 484

Strengths of Repulsions

In the 5th edition of the textbook in Chapter 3.2, Rule 4 indicates "Strengths of repulsions are in the order lone pair- lone pair > lone pair- atom> atom-atom." I am having difficulty understanding what this means. What do "lone pair- lone pair," "lone pair- atom," and...
by Rachel McMillan 3A
Tue Oct 20, 2015 5:16 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Resonance Stucture Stability
Replies: 1
Views: 241

Resonance Stucture Stability

In my discussion today, we discussed resonance structures. My TA asked if we had PF5, and removed an electron, which area would we remove the electron from: the poles or the equatorial region? My TA said it would be the equatorial region, but I am unsure as to why. Could somebody please explain this...
by Rachel McMillan 3A
Mon Oct 12, 2015 8:42 pm
Forum: Empirical & Molecular Formulas
Topic: Finding Empirical Formulas when mass % does not add to 100%
Replies: 1
Views: 1124

Finding Empirical Formulas when mass % does not add to 100%

In problem #9 of the Self-quizzes, the mass percentages of C,H, and O add to 99.89. After dividing the mass percentages by their respective molar masses and then dividing by the smallest value, I found that Hydrogen's value to be 2.379. I'm not sure which number to multiply this by to get a whole nu...
by Rachel McMillan 3A
Sun Oct 04, 2015 11:20 pm
Forum: Quantum Numbers and The H-Atom
Topic: How to find beginning & ending energy levels with wavelength
Replies: 1
Views: 452

How to find beginning & ending energy levels with wavelength

On problem #15 in the Chapter 1 homework, we were given a value of 102.6 nm as the wavelength and were asked to find the initial and final energy levels of the electrons. I first multiplied 102.6 nm by 1x10^-9 to convert the wavelength into meters. I then used the equation 1/wavelength=RZ^2((1/n1^2)...

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