Search found 33 matches

by Jasmeet Dhaliwal 3E
Fri Mar 11, 2016 12:22 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1019039

Re: Chemistry Jokes

Why did the boat conformation take the elevator?

Because it suffered from stair-ic strain
by Jasmeet Dhaliwal 3E
Fri Mar 04, 2016 5:36 pm
Forum: *Haloalkanes
Topic: CH2I?
Replies: 2
Views: 636

Re: CH2I?

CH2I is called iodomethyl because the whole molecule is a substituent, but within this molecule, iodine is also acting as a substituent; it's a case of a substituent within a substituent. If we were to consider CH3I, carbon already forms four bonds. It would not be able to bond to another atom, and ...
by Jasmeet Dhaliwal 3E
Fri Feb 26, 2016 11:44 pm
Forum: *Alkanes
Topic: 1st quiz 3 prep question 2
Replies: 3
Views: 335

Re: 1st quiz 3 prep question 2

I posted this same question a few days ago, and many other students have noticed this as well. I think it is simply an error in the answer key.
by Jasmeet Dhaliwal 3E
Wed Feb 24, 2016 5:40 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: 4.36
Replies: 1
Views: 278

Re: 4.36

Standard Gibbs Free Energy of Activation is always positive for a given reaction because it requires energy for reactant(s) to form the transition state, which has only partially formed bonds and is therefore very unstable and high in energy.
by Jasmeet Dhaliwal 3E
Wed Feb 24, 2016 5:31 pm
Forum: *Alkanes
Topic: Quiz 3 Preparation #2
Replies: 1
Views: 355

Quiz 3 Preparation #2

This question from the first quiz preparation for quiz 3 asks to name CH3CH(CH3)CH(CH2CH3)C(CH3)3. The answer key says the correct name is 2,2,4-trimethyl-3-ethylpentane. Shouldn't the answer be 3-ethyl-2,2,4-trimethylpentane to keep the substituents in alphabetical order?
by Jasmeet Dhaliwal 3E
Wed Feb 24, 2016 5:26 pm
Forum: *Cycloalkanes
Topic: Quiz 3 Preparation #5
Replies: 1
Views: 279

Quiz 3 Preparation #5

On the first quiz preparation for quiz 3, #5 asks to name a certain organic molecule with a carbon ring with two hydrogens substituted out for bromine and iodine. The answer key says the answer is 3-bromo-1-iodocyclohexane. Why isn't the answer 1-bromo-3iodocyclohexane? Because it is a ring, can't y...
by Jasmeet Dhaliwal 3E
Thu Feb 18, 2016 3:53 pm
Forum: General Rate Laws
Topic: Chemical equations and reaction orders
Replies: 1
Views: 258

Re: Chemical equations and reaction orders

The coefficient of a reactant is considered in determining a reaction's order only if the reaction is an elementary step - meaning one step of a reaction mechanism. The number of molecules (or molecularity) in this elementary step determines the order of that elementary step. If you are given an ove...
by Jasmeet Dhaliwal 3E
Tue Feb 09, 2016 6:52 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Winter 2014 Midterm #5c
Replies: 1
Views: 292

Winter 2014 Midterm #5c

This question asks to designate the w, G, q, H, E, and S as either a state function or not a state function. I got them all correct except for E. What exactly does E refer to here? It can't be internal energy, because E is considered to be not a state function. Is this the same E that means emf in e...
by Jasmeet Dhaliwal 3E
Thu Feb 04, 2016 4:06 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Question 14.35b Solution Manual Error?
Replies: 1
Views: 427

Question 14.35b Solution Manual Error?

This question asks to determine the equilibrium constant for the reaction: In3+(aq) + U3+(aq) <-> In2+(aq) + U4+(aq) My calculated value of E° matched the value in the solutions manual, +0.12 V. However, when the solutions manual plugged in this value into the equation ln K = nFE°/RT, it used the va...
by Jasmeet Dhaliwal 3E
Thu Feb 04, 2016 3:11 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Reducing Agent
Replies: 1
Views: 277

Reducing Agent

When determining whether one species is a stronger reducing agent than another, I realize that we need to consult the table of standard reduction potentials and look at which species has the largest negative reduction potential (and thus be more likely to instead be oxidized). My question is that of...
by Jasmeet Dhaliwal 3E
Thu Feb 04, 2016 1:16 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Redox reactions
Replies: 2
Views: 358

Re: Redox reactions

To determine if a redox reaction is favorable, you must first figure out the E° of the reaction. This is easiest done by splitting the overall reaction into its half-reactions. After determining which half-reaction is the oxidation reaction and which is the reduction reaction, find the respective st...
by Jasmeet Dhaliwal 3E
Thu Feb 04, 2016 1:06 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 2
Views: 365

Cell Diagrams

I have two questions regarding cell diagrams. First, does the order of two species in the same phase on the same electrode matter? For example, are both Pt(s)|Sn4+(aq), Sn2+(aq)||Cu2+|Cu and Pt(s)|Sn2+(aq), Sn4+(aq)||Cu2+|Cu acceptable? I know the book specifies that the order should be Ox, Red, but...
by Jasmeet Dhaliwal 3E
Sat Jan 30, 2016 12:57 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Voltage
Replies: 1
Views: 304

Voltage

I'm just trying to wrap my head around the meaning of voltage. I know that a 1 V = 1 J/C and that a joule is a unit of energy and a Coulomb is a unit of charge, but what exactly does it mean for a voltage to be a unit of potential difference, and how can this be expressed un terms of energy and char...
by Jasmeet Dhaliwal 3E
Mon Jan 25, 2016 5:38 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Quiz 1 Preparation #9b Error?
Replies: 1
Views: 310

Quiz 1 Preparation #9b Error?

This question asks for the delta G of the combustion of benzene, given a certain temperature, delta S (calculated in part a), and delta H for the reaction. I was just thinking that the given value of delta H (+777.00 J/mol) does not make any sense because it is a small, positive value. Most combusti...
by Jasmeet Dhaliwal 3E
Sat Jan 23, 2016 5:55 pm
Forum: General Science Questions
Topic: Kelvin Conversions
Replies: 1
Views: 325

Kelvin Conversions

When converting Celsius temperatures to Kelvin, are we supposed to use the full conversion (K = °C + 273.15°C) or should we just use the whole number 273 instead? And also, if we do use the full value, is that conversion considered exact and not limiting significant figures? It just seems like my an...
by Jasmeet Dhaliwal 3E
Fri Jan 22, 2016 6:30 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Workbook Quiz 1 Preparation Winter 2014 #10
Replies: 1
Views: 374

Workbook Quiz 1 Preparation Winter 2014 #10

The question reads: What happens to the entropy of the following system upon reaction? C12H22O11(s) + 12O2(g) -> 12CO2(g) + 11H2O(l) (I have already balanced the reaction) The answer is that the entropy increases, but why is this the case if the number of gaseous moles is the same on both the reacta...
by Jasmeet Dhaliwal 3E
Fri Jan 22, 2016 6:12 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Pick-ups for 14A
Replies: 1
Views: 328

Re: Final Pick-ups for 14A

They have been available for pick-up since the beginning of this week, in Young Hall 4006.

Their schedule is:
Tuesday, 9:30 AM - 11:30; 2:00 PM - 4:00 PM
Wednesday, 2:00 PM - 4:00 PM
Thursday, 9:30 AM - 11:30; 2:00 PM - 4:00 PM
Friday, 2:00 PM - 4:00 PM

You have until Friday, March 11th :)
by Jasmeet Dhaliwal 3E
Tue Jan 19, 2016 12:11 pm
Forum: Phase Changes & Related Calculations
Topic: Phase of Water in Combustion
Replies: 1
Views: 854

Phase of Water in Combustion

When writing combustion reactions, I am aware that the products are always carbon dioxide and water (and sometimes nitrogen). However, how do we know the phase of the water produced? That is, I've noticed that in some combustion reactions, the water produced is liquid whereas in other reactions, the...
by Jasmeet Dhaliwal 3E
Wed Jan 13, 2016 10:17 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Dissociation Energy vs. Bond Enthalpy
Replies: 1
Views: 469

Dissociation Energy vs. Bond Enthalpy

What is the difference between dissociation energy and bond enthalpy? To my knowledge, they both measure the energy required to break a bond, but the book states that these "two quantities typically differ by only a few kilojoules per mole." What contributes to this discrepancy?
by Jasmeet Dhaliwal 3E
Wed Jan 13, 2016 10:04 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Expansion Work
Replies: 1
Views: 266

Re: Expansion Work

Irreversible expansion refers to expansion by a gas that occurs when the internal and external pressures are not at equilibrium. Unlike reversible expansion, irreversible expansion occurs in one relatively quick step that does not allow the external pressure to match the internal pressure. Using the...
by Jasmeet Dhaliwal 3E
Thu Jan 07, 2016 9:44 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Change Diagram
Replies: 3
Views: 407

Re: Phase Change Diagram

First, we need to understand that the reason we feel pain from a burn is due to a rapid transfer of heat from the water/steam to the skin. The water/steam must give off enough heat until it reaches equilibrium with this skin - that is, they are the same temperature. With this knowledge in mind, we c...
by Jasmeet Dhaliwal 3E
Thu Jan 07, 2016 9:32 pm
Forum: Phase Changes & Related Calculations
Topic: Superheating
Replies: 1
Views: 285

Superheating

The textbook introduces the notion of superheating - a phenomenon where boiling initially occurs a few degrees over the boiling point before the temperature eventually drops back down to the boiling point. But isn't the boiling point defined as the temperature at which liquid molecules gain enough e...
by Jasmeet Dhaliwal 3E
Mon Nov 30, 2015 6:02 pm
Forum: Amphoteric Compounds
Topic: D-Block Metal Oxides
Replies: 1
Views: 901

D-Block Metal Oxides

I understand that many of the oxides around the zig-zag line of the metalloids are amphoteric because they are able to react with both acids and bases. I also understand that oxides of some transition metals can also act as amphoteric substances. What I am unsure of is why the ability of elements in...
by Jasmeet Dhaliwal 3E
Mon Nov 23, 2015 9:18 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Formic Acid vs. Acetic Acid - HW 12.53
Replies: 1
Views: 1115

Formic Acid vs. Acetic Acid - HW 12.53

This homework question (12.53) asks about the relative strengths of acetic acid, trichloroacetic acid, and formic acid. I understand that trichloroacetic acid is stronger than acetic acid because the chlorine atoms are able to draw the electrons away from the O-H bond, making it more polar and more ...
by Jasmeet Dhaliwal 3E
Wed Nov 18, 2015 4:31 pm
Forum: Naming
Topic: Naming
Replies: 1
Views: 265

Re: Naming

Dr. Lavelle said in class that either naming convention is acceptable.
by Jasmeet Dhaliwal 3E
Wed Nov 18, 2015 4:25 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Weak Acid Dissociation
Replies: 1
Views: 368

Weak Acid Dissociation

I understand that strong acids dissociate completely and that weak acids dissociate incompletely because the bonds in the latter are generally not weak enough to be broken by attractions with water molecules. For example, only about 1 in a 100 acetic acid molecules dissociate to form the acetate ion...
by Jasmeet Dhaliwal 3E
Fri Nov 13, 2015 12:00 am
Forum: Ideal Gases
Topic: Equilibrium Constant and Activities
Replies: 1
Views: 333

Equilibrium Constant and Activities

I recall Dr. Lavelle in lecture saying that when entering concentrations (or partial pressures) into the equilibrium expression, we use the numbers without the units. The book introduces the concept of activities, which are unitless numbers that take into account deviations from ideal behavior. So w...
by Jasmeet Dhaliwal 3E
Thu Nov 05, 2015 9:22 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Carbonate Ion as a Ligand
Replies: 1
Views: 2241

Carbonate Ion as a Ligand

I was reading in the solutions manual (answer to 17.33) that the carbonate ion can act as either a monodentate or bidentate ligand. How would one determine whether the carbonate ion will bind once or twice to the central metal atom in a coordination compound? Is it related to the size of the metal a...
by Jasmeet Dhaliwal 3E
Tue Oct 27, 2015 9:34 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Molecular Orbitals
Replies: 1
Views: 223

Molecular Orbitals

I am having difficulty imagining the positions of the molecular orbitals in space. For example, would a sigma* 2s antibonding orbital exist simultaneously with a sigma 2s bonding orbital, and would the two MO be superimposed on each other in a molecule such as diatomic oxygen, O2?
by Jasmeet Dhaliwal 3E
Thu Oct 22, 2015 12:49 pm
Forum: Hybridization
Topic: Hybridization with d orbitals
Replies: 1
Views: 297

Hybridization with d orbitals

I understand how hybridization with s and p orbitals occurs, especially with the help of Dr. Lavelle's demonstration involving his fingers in an orthogonal position, which resulted in one sigma bond and one (or two) pi bond(s). However, when the d orbital is involved - such as sp3d hybridization in ...
by Jasmeet Dhaliwal 3E
Wed Oct 14, 2015 8:34 pm
Forum: Resonance Structures
Topic: Presence of Hydrogen in Resonance Structures
Replies: 1
Views: 505

Presence of Hydrogen in Resonance Structures

The solution manual on page 82 reads: "Notice that, unlike the sulfite ion, which has three resonance forms, the presence of the hydrogen ion [in hydrogen sulfite] restricts the electrons to the oxygen atom to which it is attached. Because H is electropositive, its placement near an oxygen atom...
by Jasmeet Dhaliwal 3E
Wed Oct 07, 2015 3:56 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Crossing Nodes
Replies: 1
Views: 607

Crossing Nodes

I understand that a node is a ring or plane (radial vs. angular nodes) in which an electron has a zero probability of being found. Is it possible for an electron to "cross" a node to reach another lobe? How would this be possible if the electron would have to pass through a region where it...
by Jasmeet Dhaliwal 3E
Fri Oct 02, 2015 11:57 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra
Replies: 2
Views: 385

Atomic Spectra

When observing the absorption spectrum for Hydrogen, why is that the spectrum contains several black lines in the visible light section when the emission spectrum only reveals three lines in the visible light section (Balmer series)?

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