Search found 59 matches

by Yousif Jafar 1G
Sun Mar 10, 2019 10:06 pm
Forum: Second Order Reactions
Topic: negative in front of k
Replies: 1
Views: 31

Re: negative in front of k

We multiply the other side by the negative to get 1/[A]t - 1/[A]0.
by Yousif Jafar 1G
Sun Mar 10, 2019 10:00 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Test 2
Replies: 12
Views: 189

Re: Test 2

Also if gibbs free energy is zero, the free energy of the reactants equals that of the products
by Yousif Jafar 1G
Sun Mar 10, 2019 9:59 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Activation Energy
Replies: 7
Views: 165

Re: Activation Energy

Activation energy is the minimum quantity of energy which the reacting species must possess in order to undergo a specified reaction to reach the products and this can be shown in an energy profile diagram by showing the energy of the reactants, the energy needed to overcome the Activation energy, a...
by Yousif Jafar 1G
Sun Mar 10, 2019 9:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Final Exam
Replies: 23
Views: 237

Re: Final Exam

One of the TA's said in a review session that there should be one or two problems on it.
by Yousif Jafar 1G
Sun Mar 03, 2019 12:53 pm
Forum: Zero Order Reactions
Topic: Reaction Orders
Replies: 2
Views: 57

Re: Reaction Orders

Order of a reaction is just the relationship between the rate and the concentration of the reactant. It is calculated utilizing a chart similar to that in the notes where we see how concentration affects the rate of the experiment we are running under different scenarios. A first order reaction is a...
by Yousif Jafar 1G
Sun Mar 03, 2019 12:49 pm
Forum: Second Order Reactions
Topic: Reaction orders
Replies: 3
Views: 59

Re: Reaction orders

A first order reaction is a reaction based solely on one reactant with order of one, but a second order reaction is either two reactant each with order of one or one reactant with an order of two. Order of a reaction is just the relationship between the rate and the concentration of the reactant. It...
by Yousif Jafar 1G
Sun Mar 03, 2019 12:43 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Purpose of Kinetics
Replies: 6
Views: 101

Re: Purpose of Kinetics

Yeah so pretty much kinetics that we cover attempts to evaluate how different factors such as temperature and concentration affect our reaction rate, and we will probably use this information in 14BL as we conduct different labs.
by Yousif Jafar 1G
Fri Feb 22, 2019 10:17 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Test 2 Help
Replies: 7
Views: 117

Re: Test 2 Help

Either way we are covering the nernst equation on Monday so you could ask Ben because he is there at lecture.
by Yousif Jafar 1G
Fri Feb 22, 2019 10:11 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Hw Ch.9 #75 (6th Edition) Residual Entropy
Replies: 2
Views: 34

Re: Hw Ch.9 #75 (6th Edition) Residual Entropy

You would have to draw it out. If its cis, the molecules can only be in three positions of the octahedral and the top and bottom and the two diagonals. However, if they are trans, they can be in any of the six positions and there are two molecules that are trans for those six positions so twelve pos...
by Yousif Jafar 1G
Fri Feb 22, 2019 10:09 pm
Forum: Balancing Redox Reactions
Topic: Galcanic cell
Replies: 3
Views: 49

Re: Galcanic cell

galvanic cell is practically another word for an spontaneous reaction and voltaic is just another name.
by Yousif Jafar 1G
Sat Feb 16, 2019 10:43 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Equilibrium Constant and Gibbs Free Energy
Replies: 3
Views: 55

Re: Equilibrium Constant and Gibbs Free Energy

The equilibrium constant only comes into play when we use this equation at equilibrium
by Yousif Jafar 1G
Sat Feb 16, 2019 10:41 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: First Law
Replies: 3
Views: 66

Re: First Law

No you just use it when you are given the other variables
by Yousif Jafar 1G
Sat Feb 16, 2019 10:38 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Converting to q rev
Replies: 4
Views: 99

Re: Converting to q rev

unless it is isothermal and irreversible, you use the other formulas were change in entropy is =nRlnT2/T1
by Yousif Jafar 1G
Mon Feb 11, 2019 11:22 am
Forum: Administrative Questions and Class Announcements
Topic: Textbook glitch
Replies: 2
Views: 74

Re: Textbook glitch

there is also a pdf on Facebook
by Yousif Jafar 1G
Sat Feb 09, 2019 3:22 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Delta H
Replies: 4
Views: 62

Delta H

When does delta H = q ?
by Yousif Jafar 1G
Sat Feb 02, 2019 3:37 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Reversible reaction
Replies: 3
Views: 66

Re: Reversible reaction

Also, for irreversible reactions, they completely go to products where they do not revert to the reactants
by Yousif Jafar 1G
Sat Feb 02, 2019 3:35 pm
Forum: Phase Changes & Related Calculations
Topic: Heat Curve
Replies: 6
Views: 94

Re: Heat Curve

I think we just have to know how to read the graph and draw information from it
by Yousif Jafar 1G
Mon Jan 28, 2019 12:06 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat capacity
Replies: 1
Views: 34

Heat capacity

What does heat capacity depend on?
by Yousif Jafar 1G
Mon Jan 28, 2019 12:05 pm
Forum: Phase Changes & Related Calculations
Topic: 3rd method
Replies: 1
Views: 30

Re: 3rd method

yeah or we look it up in the book
by Yousif Jafar 1G
Sun Jan 20, 2019 3:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 12.25 7th edition
Replies: 1
Views: 33

Re: 12.25 7th edition

by using the fact that the [H3O+][OH-]=Kw
by Yousif Jafar 1G
Sun Jan 20, 2019 3:05 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 6th edition 11.73
Replies: 1
Views: 27

Re: 6th edition 11.73

because in the reactants there are less moles of gas because C is a solid so it is more favorable
by Yousif Jafar 1G
Wed Jan 16, 2019 2:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Leveled
Replies: 2
Views: 49

Leveled

Can anyone explain the concept of a strong acid being leveled?
by Yousif Jafar 1G
Sun Jan 13, 2019 1:03 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: vant Hoff factor and equation
Replies: 3
Views: 26

Re: vant Hoff factor and equation

The Van't Hoff equation is practically just the relationship between temperature, the independent value, and the Keq, the dependent value.
by Yousif Jafar 1G
Sun Jan 13, 2019 12:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: "bar" meaning
Replies: 4
Views: 76

Re: "bar" meaning

bar, atm, and PSI can all be used as a unit for pressure in our Kp values
by Yousif Jafar 1G
Sun Jan 13, 2019 12:57 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Keq
Replies: 3
Views: 43

Re: Keq

Kc should be used when talking about concentrations and it is just under the umbrella of Keq which could be either Kp or Kc.
by Yousif Jafar 1G
Sat Dec 08, 2018 10:22 am
Forum: Bronsted Acids & Bases
Topic: Arrhenius Acids and Bases
Replies: 1
Views: 50

Re: Arrhenius Acids and Bases

CH3COOH is an arrhenius acid because it can act as a proton donor. However, I think that NH3 can be justified as an Arrhenius base because it does increase the [OH-] as a product.
by Yousif Jafar 1G
Sat Dec 08, 2018 10:18 am
Forum: Empirical & Molecular Formulas
Topic: Midterm Solution
Replies: 1
Views: 162

Re: Midterm Solution

for that question the ratios are not derived from the overall molecules. What you have to do is find the moles of C in CO2, the moles of H in H2O and then add those two together. This number will be subtracted from 1 because that is the weight of your unknown compound, giving you the grams of O whic...
by Yousif Jafar 1G
Sat Dec 08, 2018 10:14 am
Forum: Properties of Light
Topic: final Grade
Replies: 3
Views: 208

Re: final Grade

also for more practice on naming you can search churro and do Lyndon's practice test which has naming
by Yousif Jafar 1G
Sat Dec 01, 2018 11:59 pm
Forum: Naming
Topic: 7th Edit 9C1
Replies: 2
Views: 43

Re: 7th Edit 9C1

NH3 actually has a charge of 0 because of the formal charges (all hydrogens=0 and N=0), so like stated, the 2- charge of sulfate would be balanced by a +3 charge of Co to make it +1
by Yousif Jafar 1G
Sat Dec 01, 2018 11:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 202
Views: 69931

Re: Saying Thank You to Dr. Lavelle

Dear Dr. Lavelle,

Thank you so much for everything this quarter. Your class has been one of my favorites and I really appreciate your positive attitude and smile you bring to every lecture. Can't wait to have you again next quarter!
by Yousif Jafar 1G
Sat Dec 01, 2018 11:51 pm
Forum: Naming
Topic: Toolbox 17.1
Replies: 1
Views: 30

Re: Toolbox 17.1

I do not think they have a relation you can do either.
by Yousif Jafar 1G
Wed Nov 21, 2018 1:55 pm
Forum: Electronegativity
Topic: regions of e- density
Replies: 4
Views: 200

Re: regions of e- density

2sp3 is the combination of the s and p orbitals into a hybrid orbital sp3 and it is the s and p orbitals of the molecule's n=2 shell
by Yousif Jafar 1G
Wed Nov 21, 2018 1:53 pm
Forum: Hybridization
Topic: Hybridization
Replies: 6
Views: 75

Re: Hybridization

Hybridization is the mixture of the different atomic orbitals, so sp3 is a combination of the s orbitals and the p orbitals. Also, the number of atomic orbitals are equal to the hybrid orbitals.
by Yousif Jafar 1G
Wed Nov 21, 2018 1:52 pm
Forum: Hybridization
Topic: Help with Confusion
Replies: 6
Views: 118

Re: Help with Confusion

I think we just need to understand the premises of pi and sigma bonds and the drawings allow you to see where they exist in 3D space.
by Yousif Jafar 1G
Mon Nov 19, 2018 11:55 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angle
Replies: 8
Views: 142

Re: Bond Angle

Like Lavelle said we do not need to memorize the experimental data just that the bond angle is slightly less than what the electron density would suggest.
by Yousif Jafar 1G
Mon Nov 19, 2018 11:52 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Double bonds
Replies: 8
Views: 158

Re: Double bonds

For Vespr its more about orientation of the bonds than the type so I don't think there is a way to dictate double bonds. When you draw in lone pairs just show an electron cloud.
by Yousif Jafar 1G
Mon Nov 19, 2018 11:51 am
Forum: Administrative Questions and Class Announcements
Topic: Discussion
Replies: 3
Views: 131

Re: Discussion

Yeah i think they still have discussion on wednesday
by Yousif Jafar 1G
Fri Nov 09, 2018 12:29 am
Forum: Bond Lengths & Energies
Topic: Larger to weaker bond correlation
Replies: 3
Views: 96

Re: Larger to weaker bond correlation

The larger the atom, the farther the bond is from the nucleus. This makes the attraction weaker as the inner electrons shield the valence electrons in the bond and they feel less pull to the larger molecules. This causes the bond to be weaker.
by Yousif Jafar 1G
Fri Nov 09, 2018 12:26 am
Forum: Resonance Structures
Topic: homework question 3.71 (6th edition)
Replies: 3
Views: 85

Re: homework question 3.71 (6th edition)

The resonance structures with the most formal charges equal to or close to 0 are the ones that contribute the most to the resonance hybrid.
by Yousif Jafar 1G
Fri Nov 09, 2018 12:24 am
Forum: Electronegativity
Topic: electronegativity trends
Replies: 6
Views: 115

Re: electronegativity trends

Electronegativity is the tendency to attract an electron. So, as you move across a period there are more protons, so the electronegativity increases. The electronegativity decreases as you move down because of the increased distance between the electron and the nucleus and more electrons are shieldi...
by Yousif Jafar 1G
Fri Nov 02, 2018 10:58 am
Forum: Dipole Moments
Topic: Midterm Dipole Moments?
Replies: 4
Views: 84

Midterm Dipole Moments?

Do we need to know today's lecture on dipole moments for the midterm?
by Yousif Jafar 1G
Fri Nov 02, 2018 10:56 am
Forum: Trends in The Periodic Table
Topic: Periodic trends
Replies: 4
Views: 74

Periodic trends

What periodic trends do we need to know for the midterm?
by Yousif Jafar 1G
Fri Nov 02, 2018 10:55 am
Forum: Electronegativity
Topic: Electronegativity calculation
Replies: 4
Views: 82

Electronegativity calculation

How is electronegativity calculated?
by Yousif Jafar 1G
Fri Oct 26, 2018 11:25 am
Forum: Ionic & Covalent Bonds
Topic: Chemical Bonding
Replies: 8
Views: 129

Re: Chemical Bonding

Yeah we go over bonding. We began from the fundamentals and I think next class we will continue to expand on chemical bonding.
by Yousif Jafar 1G
Fri Oct 26, 2018 11:20 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Covalent Radius
Replies: 2
Views: 69

Re: Covalent Radius

The covalent radius is 1/2 the distance between the centers of neighboring atoms and is when two atoms (nonmetals) are joined by covalent bonds.
by Yousif Jafar 1G
Fri Oct 26, 2018 11:17 am
Forum: Lewis Structures
Topic: Lewis Dot Order
Replies: 10
Views: 79

Lewis Dot Order

Is there a particular order for Lewis dot structures?
by Yousif Jafar 1G
Fri Oct 19, 2018 1:32 pm
Forum: *Shrodinger Equation
Topic: Schrodinger Equation
Replies: 2
Views: 70

Re: Schrodinger Equation

For the test, we just have to know of it conceptually because he stated multiple times that we do not have to understand how to calculate anything using it as that is for the physical sciences.
by Yousif Jafar 1G
Fri Oct 19, 2018 1:30 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Equation
Replies: 7
Views: 156

Re: Rydberg Equation

For the Rydberg equation, it is usually used when you want to determine the wavelength of the radiation when an electron goes from n-initial to n-final. to do that you find the frequency, nu (the one that looks like a v) and from there you utilize c=lambda/nu to find the wavelength. You can relate t...
by Yousif Jafar 1G
Fri Oct 19, 2018 1:22 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: s, p, d, f subshells in multi-electron atoms
Replies: 6
Views: 136

Re: s, p, d, f subshells in multi-electron atoms

Due to the electrostatic interactions between the nucleus and the electrons in the various orbitals, the further the electron is from the nucleus, the higher its energy. Because the s-orbital is shielding the p-orbital in the same shell, the electrons of the p-orbital will have a higher energy becau...
by Yousif Jafar 1G
Fri Oct 12, 2018 11:13 am
Forum: Properties of Light
Topic: Kinetic Energy
Replies: 3
Views: 35

Re: Kinetic Energy

No, the kinetic energy that you derive from Ek=1/2mv^2 can be related to frequency by using the formula Ek=hv-ϕ. So practically what this equation does is it sets the kinetic energy of the ejected electron equal to the energy supplied by the photon minus the work function (threshold value) that is n...
by Yousif Jafar 1G
Fri Oct 12, 2018 10:59 am
Forum: DeBroglie Equation
Topic: Wavelike properties vs classical model
Replies: 1
Views: 51

Wavelike properties vs classical model

Does c=Lambda(v) apply in quantum mechanics?
by Yousif Jafar 1G
Wed Oct 10, 2018 1:46 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Going from Spectroscopic line to Energy levels
Replies: 1
Views: 33

Re: Going from Spectroscopic line to Energy levels

So conceptually, this problem is similar to the graphs that Dr. Lavelle showed us in class. When the wavelength is shorter, so UV waves, the electron is falling from an elevated state to n=1. However when you go to a larger wavelength, visible light (400nm-700nm), the electron is falling from an ele...
by Yousif Jafar 1G
Wed Oct 03, 2018 11:45 pm
Forum: SI Units, Unit Conversions
Topic: formula units [ENDORSED]
Replies: 68
Views: 21959

Re: formula units [ENDORSED]

Moles are just a measurement kind of like a dozen. You can define what the moles, or dozen, is of so it could be atoms, molecules, formula units, or donuts. The number is the same regardless of what thing its describing.
by Yousif Jafar 1G
Wed Oct 03, 2018 11:35 pm
Forum: Balancing Chemical Reactions
Topic: Order of balancing an equation
Replies: 8
Views: 137

Re: Order of balancing an equation

I actually use a different method. I try balancing by matching singular elements and their coefficients to that of a compound because the equation is easier to deal with when it is single elements and not multiple comprising a compound.
by Yousif Jafar 1G
Wed Oct 03, 2018 11:26 pm
Forum: Limiting Reactant Calculations
Topic: Combustion Analysis? [ENDORSED]
Replies: 7
Views: 150

Re: Combustion Analysis? [ENDORSED]

I think it will be because we discussed it in lecture. The main concept is that you create water and carbon dioxide from the reactant and oxygen, and you balance the equation from there.

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