## Search found 23 matches

Thu Mar 16, 2017 7:51 pm
Forum: *Amines
Topic: Final 2013 5A
Replies: 3
Views: 621

### Re: Final 2013 5A

What does primary/secondary amine mean? How do we identify which is which? Looking at the same problem as you (5A from 2013 midterm), how can we tell that that is a secondary amine?
Thu Mar 16, 2017 5:51 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Midterm question 2A
Replies: 1
Views: 295

### Midterm question 2A

On the midterm question 2A, can someone please explain why q, w, and deltaH all = 0? I understand that deltaU=0 because it's isothermal, and I know that w=-q and deltaH=q so those must all be equal or equal to the negative. But I don't understand why they are all 0. Any help would be appreciated!
Wed Mar 15, 2017 8:53 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: How to determine higher stability
Replies: 2
Views: 364

### Re: How to determine higher stability

On page 111 in the course reader, it says "bigger substituents have higher preference for equatorial position." This holds true for all complex molecules, so the chlorine and bromine substituents always prefer equatorial - it is always more stable if they are in this position versus axial.
Wed Mar 15, 2017 8:49 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Flipping an Ecell equation
Replies: 1
Views: 384

### Flipping an Ecell equation

If we aren't told which reaction is reduced and which is oxidized and are given both Ecell values as positive, how do we know which equation to flip/switch the Ecell sign? Both reactions are initially written as reduction (with solids being formed).
Tue Mar 14, 2017 12:28 am
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 229
Views: 103990

### Re: Saying Thank You to Dr. Lavelle

Dr. Lavelle, Thank you for your constant support, extra office hours and resources, and for doing everything you can to help us succeed. I truly felt like you wanted us to do well in your class, and that is very much appreciated especially in such a large student population. Thank you for selflessly...
Tue Mar 07, 2017 12:25 am
Forum: *Alkanes
Topic: Naming [ENDORSED]
Replies: 92
Views: 8754

### Re: Naming[ENDORSED]

On page 3 of the OChem textbook at the bottom, how do you get the "-diene" at the end of the molecule 2-Methyl-1,3-butadiene? Also, I'm confused on how to start the numbering for this example. Which Carbon is 1, and what order/direction do you go from there?
Tue Mar 07, 2017 12:08 am
Forum: *Alkanes
Topic: Drawing structures for Quiz 3
Replies: 1
Views: 306

### Drawing structures for Quiz 3

Is it acceptable to draw the line structures, or should we draw out the Lewis structures for the quiz? We have done a variety of both in class.
Mon Mar 06, 2017 11:59 pm
Replies: 1
Views: 509

Is there such thing as nucleophilic addition, or is it only electrophilic addition and nucleophilic substitution? Is the way to tell between the two whether or not the number of molecules goes from 2 to 1 (addition) versus 2 to 2 (substitution)? Is there any other way we should know to differentiate...
Mon Mar 06, 2017 11:53 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Reaction steps and transition states
Replies: 1
Views: 302

### Reaction steps and transition states

Are the number of steps of a reaction always equal to the number of transition states? And is the number of intermediates always one less than the former? I'm noticing this trend, but want to make sure it's accurate for all curves (especially the first part). Thanks!
Sat Feb 11, 2017 7:57 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Zero, First, and Second Reactions
Replies: 1
Views: 228

### Zero, First, and Second Reactions

I know that these three reactions are related through derivatives and their respective graphs and slopes, but is it to the extent that the second reaction graph is the derivative of the first reaction graph, and the derivative of that is the zero reaction graph? I was thinking these could correlate ...
Sun Jan 29, 2017 1:15 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: When to use which q= equation?
Replies: 1
Views: 486

### When to use which q= equation?

I am confused about when to use q=mCpdeltaT (where m=mass), q=nCpdeltaT (where n=number of moles), and q=CpdeltaT? These three equations are very similar yet are all used in different problems. I'm having a hard time figuring out when to use which equation. Any help would be appreciated!
Thu Jan 26, 2017 9:58 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework question 8.23
Replies: 1
Views: 274

### Homework question 8.23

A calorimeter was calibrated with an electric heater, which supplied 22.5 kJ of energy as heat to the calorimeter and increased the temperature of the calorimeter and its water bath from 22.45 degrees Celsius to 23.97 degrees Celsius. What is the heat capacity of the calorimeter? How do you solve th...
Thu Jan 26, 2017 8:28 pm
Forum: Calculating Work of Expansion
Topic: Converting L/atm to Joules
Replies: 1
Views: 620

### Converting L/atm to Joules

A problem from chapter 8 requires you to convert units L/atm to J using the "equivalency of the ideal gas constants" (taken from the answer book). I am not sure what that means or how to make this conversion.
Sat Dec 03, 2016 5:04 pm
Forum: Naming
Topic: Order of Naming Coordination Compound
Replies: 1
Views: 367

### Order of Naming Coordination Compound

When naming a coordination compound, does the order of the formula matter? For instance, when writing the formula for triamminetrichloronickel(IV) sulfate, is there a difference (in science and in grading) between writing [NiCl 3 (NH 3 ) 3 ] 2 SO 4 (which is how the answer is written) and [(NH 3 ) 3...
Fri Dec 02, 2016 1:17 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: D orbital
Replies: 3
Views: 458

### Re: D orbital

d orbital electrons are usually ejected before s orbital because their bond to the central atom is significantly weaker.
Wed Nov 30, 2016 7:22 pm
Forum: *Titrations & Titration Calculations
Topic: Chapter 13 Problem 3
Replies: 1
Views: 471

### Re: Chapter 13 Problem 3

The Henderson Hasselbalch equation could definitely be used for part A, especially since the concentrations of the conjugate acid and base are the same. These equal concentrations would cancel out the log[base/acid], therefore making it pKa=pH. As for part B, I think you must use the ICE table becau...
Tue Nov 15, 2016 11:23 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Shift in Equilibria
Replies: 1
Views: 261

### Re: Shift in Equilibria

A shift in equilibria means that either the reactant side or product side has too much substance and therefore more reaction will take place in order for the overall reaction to remain in a balanced equilibria (which means the amount chemically reacting from reactants to products is equal to the opp...
Sun Nov 13, 2016 11:49 pm
Forum: Naming
Topic: Naming Ligands
Replies: 1
Views: 257

### Naming Ligands

In our course reader, ligand names are Fluoro for F-, Chloro for Cl-, Bromo for Br-, etc. However, in the textbook on page 742, they are fluorido, chlorido, bromido, etc. I am guessing that our course reader has the correct names that we will be tested on? I just want to make sure I'm learning the r...
Mon Oct 31, 2016 10:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs on Linear Molecule
Replies: 3
Views: 706

### Re: Lone Pairs on Linear Molecule

No, lone pairs on a molecule would prohibit it from being linear shape. Both AX2E1 and AX2E2 are bent because of the effect of the lone pairs.
Wed Oct 19, 2016 7:44 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: writing electron configurations
Replies: 1
Views: 223

### writing electron configurations

I am still slightly confused on what order to write electron configurations in. In my high school class, we were taught to write it just going across the periodic table so the numbers would be out of order. For instance, when writing the configuration for Tantalum (Ta), I was taught to write it like...
Thu Oct 13, 2016 8:40 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7774
Views: 1073645

### Re: Post All Chemistry Jokes Here

Did you hear about the man who got cooled to absolute zero? Don't worry, he's 0K now.

Why did the acid go to the gym? To become a buffer solution.

yay for chemistry jokes!
Wed Oct 05, 2016 3:50 pm
Forum: Molarity, Solutions, Dilutions
Topic: Problem E15 from textbook
Replies: 1
Views: 330

### Problem E15 from textbook

The molar mass of the metal hydroxide M(OH)subscript2 is 74.10 g/mol. What is the molar mass of the sulfide of this metal?

The solutions manual shows that the answer involves Calcium and CaS, but I don't know where the Calcium came from or how I am supposed to know to involve it in this problem.
Fri Sep 30, 2016 10:23 am
Forum: Properties of Electrons
Topic: Electron Energy Emission
Replies: 1
Views: 285

### Electron Energy Emission

Do all electrons have the same minimum energy required to be emitted, or can various factors (heat, type of atom/molecule) affect the necessary energy for the electron's emission?