## Search found 27 matches

Wed Mar 15, 2017 11:19 am
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Gauche and Anti conformation
Replies: 1
Views: 376

### Re: Gauche and Anti conformation

Gauche can apply to molecules in which there are large substituents and that specific conformation refers to the position in which the largest groups are not eclipsed but rather 60 degrees apart. With the gauche conformation, the amount of steric strain increases as the size of the molecule grows. I...
Tue Mar 07, 2017 11:50 am
Forum: *Alkanes
Topic: Alkane name
Replies: 3
Views: 401

### Alkane name

What is the name of CH3CH2CH(CH3)CH2CH2CH2CH3?
Mon Feb 27, 2017 3:20 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Prep quiz 2 #11, 5
Replies: 2
Views: 435

### Re: Prep quiz 2 #11, 5

Number 5 can actually be known from reading the textbook, more specifically, at the bottom of 641 it says "the higher the activation energy, the stronger is the temperature dependence of the rate constant." Therefore, since we are dealing with a low activation energy, the answer is B. For ...
Wed Feb 22, 2017 9:51 pm
Forum: General Rate Laws
Topic: Rxn Rates
Replies: 3
Views: 284

### Re: Rxn Rates

It depends on the order of the order of the reaction. Different orders give unique integrated rate laws. For example, for a zero order reaction you would have [A] = -kt + [A]0. To get this formula you would set -d[A]/dt equal to just the rate constant k.
Wed Feb 22, 2017 12:47 pm
Forum: General Rate Laws
Topic: Rxn Rates
Replies: 3
Views: 284

### Re: Rxn Rates

You can use an integrated rate law if given that specific information. Also, those two equations are related because when set equal to each other, you can derive the integrated rate law for the reaction.
Mon Feb 13, 2017 3:01 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Stability of Molecules
Replies: 1
Views: 300

### Re: Stability of Molecules

In the solutions manual, the explanation puts Fe3O4 as a reactant and Fe2O3 as a product. Then, Gibbs free energy is calculated and the value is negative which signifies that the reaction is spontaneous. Therefore, it concludes that Fe2O3 is thermodynamically more stable.
Mon Feb 13, 2017 10:35 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: deciding which is oxidized/reduced
Replies: 2
Views: 334

### Re: deciding which is oxidized/reduced

The best way to determine which half reaction is being oxidized or reduced is to take note of the standard reduction potentials for each half reaction. It's not given in the problem but Professor Lavelle has said before that we would be given a table with those potentials when needed. Furthermore, i...
Tue Feb 07, 2017 12:12 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 4
Views: 549

### Re: Cell Diagrams

The anode half reaction is on the left whereas the cathode reaction is on the right. The two vertical lines separate those half reactions. Also, the single vertical line notes the difference between a reactant and product.
Tue Feb 07, 2017 11:24 am
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: 429

### Re: Calculating pH

I have the same question! The textbook example was confusing (pg 590-591).
Thu Feb 02, 2017 4:46 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Using an inert electrode
Replies: 2
Views: 236

### Re: Using an inert electrode

Inert electrodes act as a source or sink for electrons and don't chemically affect your reaction. For example, if you have a reactant that cannot work as an electrode like I2 then that's when you use an inert electrode.
Tue Jan 24, 2017 10:33 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Negative change in entropy
Replies: 1
Views: 254

### Negative change in entropy

If a system has negative entropy, is there work being done by or on the system?
Tue Jan 17, 2017 12:49 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: relationship between delta H and q [ENDORSED]
Replies: 4
Views: 1556

### Re: relationship between delta H and q[ENDORSED]

Great question, delta H and q are interchangeable only when there is heat under constant pressure.
Fri Jan 13, 2017 2:55 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy
Replies: 2
Views: 267

### Re: Enthalpy

In my opinion, it is best to draw out lewis structures for the reaction to see exactly which bonds were broken and created.
Tue Nov 29, 2016 8:40 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Relationship between pKa and pKb
Replies: 2
Views: 388

### Re: Relationship between pKa and pKb

I don't know where you heard that but I thought that when the pKa increases that means the pKb must decrease. If together they equal 14, then if one increases the other decreases.
Fri Nov 25, 2016 10:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chapter 11 Qs. #67
Replies: 1
Views: 250

### Re: Chapter 11 Qs. #67

I'm pretty sure you can solve the problem using the original values given in the textbook, but the solutions manual just shifts the initial values to the reactants because it will be easier to solve. So 1 mole is subtracted from H2 and 1 mole from Cl2 and those two moles together are added to HCl. I...
Fri Nov 25, 2016 10:10 pm
Forum: Amphoteric Compounds
Topic: Amphoteric compounds
Replies: 1
Views: 303

### Re: Amphoteric compounds

I think Bronsted acids, the textbook uses the Bronsted theory for the most part.
Fri Nov 18, 2016 4:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Water in K calculation
Replies: 3
Views: 419

### Water in K calculation

When calculating the value of K, do we keep water if it is in a gas phase? I know it is not included in the K calculation if is a liquid since it is a solvent.
Wed Nov 09, 2016 7:46 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination number? [ENDORSED]
Replies: 1
Views: 250

### Coordination number?[ENDORSED]

So let's say I had K3[Cr(CN)6].... would the coordination number be the number of bonds of the metal within the brackets or include the total number of bonds the transition metal has? So basically would my coordination for this example be 6 or 9?
Wed Nov 09, 2016 7:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Determining K or Q [ENDORSED]
Replies: 3
Views: 331

### Re: Determining K or Q[ENDORSED]

So basically the constant Q can be used at any time during the reaction while K is only when the reaction is at chemical equilibrium.
Fri Nov 04, 2016 10:20 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Bond Order?
Replies: 5
Views: 636

### Bond Order?

So if the bond order turns out to be 2, does that mean there is a double bond?
Thu Oct 27, 2016 5:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Notation used in VSEPR [ENDORSED]
Replies: 1
Views: 316

### Re: Notation used in VSEPR[ENDORSED]

I think we are going to need it for the midterm, I was taking a look at past midterms and the question asked for the VSEPR notation.
Thu Oct 20, 2016 2:54 pm
Forum: Properties of Light
Topic: Quiz 1 #5 [ENDORSED]
Replies: 1
Views: 337

### Re: Quiz 1 #5[ENDORSED]

The concept here would actually be atomic spectra because the question clearly states that the light only excites the atom. Electrons are excited to different n levels, which means light was absorbed to reach that level and it is also emitted when the electron returns to its original state. Photoele...
Thu Oct 20, 2016 9:58 am
Forum: Ionic & Covalent Bonds
Topic: NH4Cl question 3.39
Replies: 1
Views: 262

### Re: NH4Cl question 3.39

NH4Cl is drawn with brackets because it is an ionic compound and the minus and plus sign superscripts signify the charges. NH4 by itself has covalent bonds, however with the Cl anion, ammonium chloride is bonded through an ionic bond.
Thu Oct 13, 2016 11:18 am
Forum: Trends in The Periodic Table
Topic: Chapter 2, Homework Problem 2.93
Replies: 2
Views: 413

### Re: Chapter 2, Homework Problem 2.93

I was confused with the same thing too, the textbook even states that the Sodium cation is smaller than the parent Sodium atom, but the solutions manual says it becomes bigger.
Thu Oct 06, 2016 8:14 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty in Velocity? [ENDORSED]
Replies: 1
Views: 295

### Uncertainty in Velocity?[ENDORSED]

Can someone explain whether the uncertainty in velocity is the number that follows the +/- (such as 6.00 m/s +/- 5 m/s)... or if it is double that amount since the spread would be 10m/s?
Mon Oct 03, 2016 4:37 pm
Forum: Significant Figures
Topic: Significant figures in textbook Ex. 1.7 (p. 18) [ENDORSED]
Replies: 2
Views: 430

### Re: Significant figures in textbook Ex. 1.7 (p. 18)[ENDORSED]

I'm pretty sure the 2 represents the fact that the number 1.0 x 10^-3 has to be doubled since that will get you the correct indeterminacy in velocity.
Mon Sep 26, 2016 9:10 pm
Forum: Student Social/Study Group
Topic: Chem 14A Delta Terrace Study Group!
Replies: 3
Views: 591

### Re: Chem 14A Delta Terrace Study Group!

Yes of course! What time would be most suitable for you?