Search found 21 matches

by Daniel Fernandez 3H
Fri Mar 17, 2017 11:59 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: final 2014 Question 2
Replies: 1
Views: 253

final 2014 Question 2

What gives us the ability to predict that Delta s of the system is negative?
by Daniel Fernandez 3H
Sat Mar 11, 2017 11:49 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Eclipsed and staggered
Replies: 1
Views: 322

Eclipsed and staggered

Hi!
I was wondering if molecules tried to return to staggered position once they are in eclipsed position since it is a lower energy state or if they stay in a position until another molecule collides with them?
Thank you!
by Daniel Fernandez 3H
Fri Mar 03, 2017 11:30 pm
Forum: *Nucleophiles
Topic: Self-Test 4.1A
Replies: 1
Views: 299

Self-Test 4.1A

Hi!
I was wondering why I- is more nucleophilic than Cl- as stated on page 147 in the Organic chem book. It says that it is because of polarzability but I was wondering if someone could explain it in detail. I thought that since Iodine is a smaller atom it would act more nucleophilic.
Thank you!
by Daniel Fernandez 3H
Sat Feb 25, 2017 3:58 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: 15.89 [ENDORSED]
Replies: 1
Views: 252

15.89 [ENDORSED]

Hi!
In general,How do you figure out which step is the rate determining one?
by Daniel Fernandez 3H
Sat Feb 18, 2017 11:31 pm
Forum: General Rate Laws
Topic: Quiz 2 preparation #2
Replies: 2
Views: 353

Quiz 2 preparation #2

Hi!
I had a question about number 2 on quiz 2 prep.
What is the difference between reaction rate and rate constant?
Thank you!
by Daniel Fernandez 3H
Sat Feb 11, 2017 11:57 pm
Forum: Balancing Redox Reactions
Topic: Question 14.25
Replies: 2
Views: 318

Question 14.25

Hi! I had a question on 14.25 Arrange the following metals in order of increasing strength as reducing agents for species in aqueous solution: (a) Cu, Zn, Cr, Fe; For (a) why is the answer Cu <Fe < Zn < Cr? Isn't Zn the most electronegative,which would make it grab electrons at a higher strength tha...
by Daniel Fernandez 3H
Fri Feb 03, 2017 1:59 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 9.43
Replies: 2
Views: 439

9.43

Hello! 9.43 Suppose that 50.0 g of H 2 O(l) at 20.0 $C is mixed with 65.0 g of H 2 O(l) at 50.0 C at constant atmospheric pressure in a thermally insulated vessel. Calculate "S and "S tot for the process What equation for S am I supposed to use and how do I mathematically connect the diffe...
by Daniel Fernandez 3H
Wed Jan 25, 2017 10:45 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy Questions
Replies: 1
Views: 266

Gibbs Free Energy Questions

Hello,
What is free energy and how is it a state function? Also, how are entropy and enthalpy related to free energy?
by Daniel Fernandez 3H
Sat Jan 21, 2017 11:05 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy vs Enthalpy of formation [ENDORSED]
Replies: 1
Views: 306

Bond Enthalpy vs Enthalpy of formation [ENDORSED]

Hello,
What is the difference between bond enthalpies and enthalpy of formation?
by Daniel Fernandez 3H
Fri Jan 13, 2017 2:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Chapter 8 problem 31 question
Replies: 2
Views: 387

Chapter 8 problem 31 question

8.31 Calculate the heat released by 5.025 g of Kr(g) at
0.400 atm as it cools from 97.6 ’C to 25.0 ’C at (a) constant
pressure and (b) constant volume. Assume that krypton behaves
as an ideal gas
What equation should I be using?
by Daniel Fernandez 3H
Fri Dec 02, 2016 8:57 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Chapter 12 problem 79
Replies: 2
Views: 504

Chapter 12 problem 79

12.79
Calculate the pH of 0.15 m H 2 SO 4 (aq) at 25 C.
by Daniel Fernandez 3H
Thu Dec 01, 2016 4:22 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Chapter 12 question 27
Replies: 1
Views: 911

Chapter 12 question 27

A careless laboratory technician wants to prepare
200.0 mL of a 0.025 m HCl(aq) solution, but uses a 250.0-mL
volumetric fl ask by mistake. (a) What would the pH of the
desired solution have been? (b) What will be the actual pH of
the solution as prepared?
by Daniel Fernandez 3H
Tue Nov 22, 2016 11:54 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chapter 11 problem 115
Replies: 1
Views: 306

Chapter 11 problem 115

11.115 The overall photosynthesis reaction is 6 CO 2 (g) ! 6 H 2 O(l) S C 6 H 12 O 6 (aq) ! 6 O 2 (g), and ’H# " !2802 kJ. Suppose that the reaction is at equilibrium. State the effect that each of the following changes will have on the equilibrium composition (tends to shift toward the formati...
by Daniel Fernandez 3H
Sun Nov 13, 2016 1:39 pm
Forum: Photoelectric Effect
Topic: Midterm question #3A
Replies: 2
Views: 525

Midterm question #3A

Why do we have to divide the threshold energy by Avogadro’s constant?
by Daniel Fernandez 3H
Tue Nov 08, 2016 3:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium [ENDORSED]
Replies: 1
Views: 268

Chemical Equilibrium [ENDORSED]

What has to happen to a reaction for it to reach chemical equilibrium? Are all reactions capable of being reversed?
by Daniel Fernandez 3H
Fri Nov 04, 2016 4:10 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Molecular orbital theory question
Replies: 2
Views: 333

Molecular orbital theory question

What is the difference between an anti-molecular orbital and a bonding one? Additionally, why do electrons fill up the bonding orbitals first?
by Daniel Fernandez 3H
Mon Oct 24, 2016 9:00 pm
Forum: Electronegativity
Topic: Electron affinity vs Electronegativity vs. Ionization energy [ENDORSED]
Replies: 2
Views: 1154

Electron affinity vs Electronegativity vs. Ionization energy [ENDORSED]

What is the difference between electron affinity, electronegativity, and ionization energy?
Thank you
by Daniel Fernandez 3H
Tue Oct 18, 2016 2:25 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 2.55
Replies: 3
Views: 821

2.55

Give the notation for the valence-shell configuration
(including the outermost d-electrons) of (a) the alkali metals;
(b) Group 15 elements; (c) Group 5 transition metals;
(d) “coinage” metals (Cu, Ag, Au)
by Daniel Fernandez 3H
Sat Oct 15, 2016 7:10 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Chapter 1 question 15
Replies: 4
Views: 689

Chapter 1 question 15

In the ultraviolet spectrum of atomic hydrogen, a line is
observed at 102.6 nm. Determine the values of n for the initial
and final energy levels of the electron during the emission of
energy that leads to this spectral line.
by Daniel Fernandez 3H
Sat Oct 08, 2016 8:46 pm
Forum: Photoelectric Effect
Topic: Quiz Preparation #5 [ENDORSED]
Replies: 1
Views: 328

Quiz Preparation #5 [ENDORSED]

The question is:
No electrons are emitted from the surface of metallic Cs until frequency of the radiation reaches 4.50x10^16 Hz. Find the energy required to remove the electron from the metal surface.
What am I supposed to use for kinetic energy?
by Daniel Fernandez 3H
Mon Sep 26, 2016 10:05 pm
Forum: Properties of Light
Topic: Magnetic and Electric fields
Replies: 4
Views: 523

Magnetic and Electric fields

How do magnetic fields and electric fields relate to each other? I know the diagram has them perpendicular to each other but what does that mean in relation to light?

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