Search found 31 matches

by Mikaela Gareeb 3G
Sun Mar 19, 2017 5:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 186
Views: 39321

Re: Saying Thank You to Dr. Lavelle

Dr. Lavelle, Thank you for not only helping me understand chemistry better, but also for helping ease the transition from high school into college. You have been understanding every step of the way and have supported me, as well as your thousands of other students, in this exciting, yet nerve-wracki...
by Mikaela Gareeb 3G
Sun Mar 12, 2017 11:11 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7023
Views: 772280

Re: Post All Chemistry Jokes Here

If you're not part of the solution, you're part of the precipitate.

What's "HIJKLMNO"?
H2O

Why does a hamburger have lower energy than a steak?
It's in the ground state
by Mikaela Gareeb 3G
Thu Mar 09, 2017 12:39 am
Forum: *Electrophilic Addition
Topic: Electrophilic Addition Example in Quiz 3 Prep
Replies: 2
Views: 302

Re: Electrophilic Addition Example in Quiz 3 Prep

Electrophilic addition reactions are always two step mechanisms (and therefore always have two transition states). On the other hand SN2 reactions are all one step reactions with one transition state.
by Mikaela Gareeb 3G
Sun Mar 05, 2017 8:55 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7023
Views: 772280

Re: Post All Chemistry Jokes Here

Did you hear about the guy who got cooled to absolute zero ?
He's 0K now

What's a girl's future best friend?
Carbon
C (graphite) -> C (diamond)
by Mikaela Gareeb 3G
Wed Mar 01, 2017 4:13 pm
Forum: *Complex Reaction Coordinate Diagrams
Topic: IUPAC vs. Common names
Replies: 1
Views: 336

Re: IUPAC vs. Common names

Common names apply to specific molecules, but Lavelle said that he's not going to specify the type of naming that we must do (IUPAC vs common), so we can just use IUPAC any time a question asks to name a molecule.
by Mikaela Gareeb 3G
Sat Feb 25, 2017 5:35 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7023
Views: 772280

Re: Post All Chemistry Jokes Here

What do you call iron blowing in the wind?
Febreze

What do dipoles say in passing"
"Have you got a moment?"
by Mikaela Gareeb 3G
Wed Feb 22, 2017 1:28 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Speed of reaction
Replies: 1
Views: 237

Re: Speed of reaction

The question will clarify which elementary reaction is faster and slower because you can't determine that by just looking at the steps.
by Mikaela Gareeb 3G
Sun Feb 19, 2017 1:12 pm
Forum: General Rate Laws
Topic: Pre-Equilibrium Approach
Replies: 1
Views: 205

Re: Pre-Equilibrium Approach

We know that step two is going to be the slow step because there is going to be a buildup of the intermediate from step one; therefore, because step one is progressing so quickly, there will be a bottle-neck effect.
by Mikaela Gareeb 3G
Sun Feb 12, 2017 10:46 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Finding Ka
Replies: 2
Views: 290

Re: Finding Ka

Kb would apply to a basic reaction, so I assume that you would solve it the same way as you would for an acidic reaction.
by Mikaela Gareeb 3G
Thu Feb 09, 2017 10:48 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 3
Views: 244

Re: Cell Diagrams

The electrode (inert conductor) should sandwich the molecules being oxidized and reduced, but other than that the order of the molecules within the anode and cathode does not matter. It's important to know where to put the lines that separate the molecules- draw a line when the molecules are in diff...
by Mikaela Gareeb 3G
Sun Feb 05, 2017 4:18 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7023
Views: 772280

Re: Post All Chemistry Jokes Here

An optimist sees the glass half-full and a pessimist sees the glass-half empty, but the chemist sees the glass half-filled with liquid and half-filled with gas... unless the system is in a vacuum.
by Mikaela Gareeb 3G
Mon Jan 30, 2017 9:39 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.65
Replies: 1
Views: 280

Re: 8.65

First, you must create an equation in which the only product is N2O5 by manipulating the two given equations. Once you attain the standard enthalpy of the reaction for your new equation, solve for the standard enthalpy of formation for N2O5 by using the formula: DeltaH = 2DeltaH(N2O5) - 3DeltaH(O2)-...
by Mikaela Gareeb 3G
Wed Jan 25, 2017 1:48 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Homework Question 9.15 (a)
Replies: 1
Views: 271

Re: Homework Question 9.15 (a)

DeltaS=q/T = DeltaH/T = ((1.00 mol)(-6.01 kJ/mol))/(273.2 K).
-6.01 kJ/mol is the enthalpy of fusion (melting), and since freezing is the opposite of melting you just take the negative of delta H. Also, the freezing point of water is at 273.2 K- both of these values are found in table 8.3.
by Mikaela Gareeb 3G
Sun Jan 22, 2017 11:23 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.57
Replies: 4
Views: 407

Re: 8.57

You're adding up the enthalpies of the reaction. You are given an equation and the enthalpies of combustion for each of the individual molecules, so when you create a combustion equation for each of the molecules (remember that combustion is a molecule + oxygen -> carbon dioxide + water) you will ha...
by Mikaela Gareeb 3G
Sun Jan 22, 2017 11:13 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework 8.73 a
Replies: 3
Views: 332

Re: Homework 8.73 a

I'm not sure why the solution manual doesn't break the C-H bonds that are on the reactants side (as well as the products side), but this is how I did it: break 1 C-C triple bond: (3 mol)(837 kJ/mol) break 2 H-C single bonds: (3 mol)(412 kJ/mol) form 6 C-C resonance bonds: -(6 mol)(518 kJ/mol) form 6...
by Mikaela Gareeb 3G
Wed Jan 18, 2017 8:57 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Calorimeter questions
Replies: 2
Views: 178

Re: Calorimeter questions

When HCl and NaOH react with each other, H2O and NaCl form, but because NaCl is a salt, it doesn't react with anything. Whenever you are using density, you should also use specific heat capacity because density times volume equals mass which can be multiplied by specific heat capacity and temperatur...
by Mikaela Gareeb 3G
Thu Jan 12, 2017 1:58 pm
Forum: Phase Changes & Related Calculations
Topic: Most Helpful Resource
Replies: 14
Views: 1114

Re: Most Helpful Resource

I found the UA hours especially helpful because there are so many of them, but also because there are fewer people there so you can ask more questions. Also, since the UAs are usually third- or forth-years they can give you practice problems from earlier versions of the course reader.
by Mikaela Gareeb 3G
Wed Nov 30, 2016 5:00 pm
Forum: *Indicators
Topic: Importance of Indicators
Replies: 2
Views: 1524

Re: Importance of Indicators

I think we need to know what they are (weak acids that change color when the stoichiometric point is reached), but when I asked Lavelle during office hours, he said that we don't need to know the colors.
by Mikaela Gareeb 3G
Wed Nov 30, 2016 4:57 pm
Forum: General Science Questions
Topic: chemical equilibrium
Replies: 1
Views: 469

Re: chemical equilibrium

If the reaction is endothermic (requires heat), then heating the equation will favor products (forward reaction) whereas if the reaction is exothermic (releases heat), then heating will favor reactants (reverse reaction). Also, since pressure and volume are inversely proportional (as pressure increa...
by Mikaela Gareeb 3G
Thu Nov 24, 2016 9:56 am
Forum: Lewis Acids & Bases
Topic: page 161 of the course reader
Replies: 1
Views: 285

Re: page 161 of the course reader

The question is asking for the pH of NH4Cl (an acidic salt) and because it dissociates into NH3 and H3O+, we need to find the concentration of H3O+ by doing an ICE chart. At equilibrium we find that the concentration of of H3O+ is x, and by solving for x we get 9.2e-6, so by using the equation pH=-l...
by Mikaela Gareeb 3G
Wed Nov 16, 2016 12:19 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: MO diagrams for ions
Replies: 3
Views: 388

MO diagrams for ions

If you are given an ion such as NO+ and are told to draw the MO diagram for it, which atom would the electron be taken from? Would the N have one less electron because it is less electronegative than O and therefore able to lose an electron more easily?
by Mikaela Gareeb 3G
Tue Nov 08, 2016 11:14 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7023
Views: 772280

Re: Post All Chemistry Jokes Here

What kind of fish is made out of two sodium atoms?
Tuna (2Na)
by Mikaela Gareeb 3G
Fri Nov 04, 2016 12:34 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: 4.61 Homework Question
Replies: 3
Views: 354

Re: 4.61 Homework Question

CO:(sigma 2s)^2 (sigma 2s*)^2 (pi 2p)^4 (sigma 2p)^22. Bond order=3
CO+: (sigma 2s)^2 (sigma 2s*)^2 (pi 2p)^4 (sigma 2p)^11. Bond order=2.5
Because CO has a higher bond order, it has a stronger bond.
by Mikaela Gareeb 3G
Thu Oct 27, 2016 2:03 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7023
Views: 772280

Re: Post All Chemistry Jokes Here

Whats the chemical formula for banana?
BaNa2
by Mikaela Gareeb 3G
Thu Oct 27, 2016 1:59 pm
Forum: Administrative Questions and Class Announcements
Topic: MidTerm Review [ENDORSED]
Replies: 4
Views: 507

Re: MidTerm Review [ENDORSED]

Lavelle said that the best way to study for the midterm is by reviewing the past two quizzes which means that the midterm would be up to chapter three. However, I'm not sure if he would put anything from chapter four on the midterm, but if I hear anything I'll update this post.
by Mikaela Gareeb 3G
Tue Oct 25, 2016 3:06 pm
Forum: Lewis Structures
Topic: Lewis Structure Octet Rule Exceptions
Replies: 3
Views: 529

Re: Lewis Structure Octet Rule Exceptions

H, He, Li, and Be do not follow the octet rule. Also, B can form less than an octet, such as BF3, but it can also attain an extra electron to fulfill the octet rule, such as BF4^-
by Mikaela Gareeb 3G
Tue Oct 25, 2016 2:58 pm
Forum: Resonance Structures
Topic: Resonance structures [ENDORSED]
Replies: 3
Views: 418

Re: Resonance structures [ENDORSED]

It's possible to have resonance structures in which the resonance occurs with different elements so long as, in this case, nitrogen and oxygen do not have expanded octets. Also, be aware of the formal charge; if the compound is neutral and double bonding the nitrogen or oxygen gives you an overall n...
by Mikaela Gareeb 3G
Fri Oct 21, 2016 1:52 pm
Forum: Resonance Structures
Topic: Radicals
Replies: 3
Views: 392

Re: Radicals

Radicals will react with an electron from a DNA molecule and oxidize it, but antioxidants (like the ones in blueberries) catch radicals before the can cause damage.
by Mikaela Gareeb 3G
Wed Oct 12, 2016 4:39 pm
Forum: SI Units, Unit Conversions
Topic: Conversions
Replies: 2
Views: 269

Re: Conversions

For all equations that include joules use kilograms- this includes the De Broglie equation and Heisenberg Uncertainty Principle. Also, always use liters for molarity. To remember to convert units just look at the units you want in your answer and keep in mind that 1 J = 1 kg*m^2/s^2.
by Mikaela Gareeb 3G
Wed Oct 05, 2016 2:32 pm
Forum: Properties of Electrons
Topic: Atomic Spectra Requirements [ENDORSED]
Replies: 3
Views: 355

Re: Atomic Spectra Requirements [ENDORSED]

For the chapter one homework questions, it asked to determine the type of electromagnetic radiation from the wavelength calculated, so I would assume that we should know the different regions for the quiz next week.
by Mikaela Gareeb 3G
Wed Sep 28, 2016 8:09 pm
Forum: Properties of Light
Topic: Kinetic Energy
Replies: 4
Views: 659

Re: Kinetic Energy

Total energy-threshold energy=excess energy describes the photoelectric effect in steps. In other words, a certain amount of energy is inputed by a photon and the process of removing an electron takes up some energy, but if there is some left over, then the electron takes the excess/kinetic energy w...

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