Search found 60 matches

Mon Mar 11, 2019 7:34 pm
Forum: General Rate Laws
Topic: Unique Rate Law
Replies: 4
Views: 178

Re: Unique Rate Law

Basically, you multiply the instantaneous rate to the inverse stoichiometric coefficient.
Mon Mar 11, 2019 7:30 pm
Forum: General Rate Laws
Topic: 7A15 how to find order of reactant (no similar C values)
Replies: 2
Views: 108

Re: 7A15 how to find order of reactant (no similar C values)

You would first compare the rate laws for different experiments. You would solve for the exponents as you would cancel out like terms. In terms of C you would compare trials 1 and 4 and then you would see through the comparison it would be 7/4 to the nth power = 1. Therefore n is equal to 0.
Mon Mar 11, 2019 7:27 pm
Forum: General Rate Laws
Topic: what if
Replies: 3
Views: 145

Re: what if

It will still be second order since each reactant is first order.
Mon Mar 11, 2019 7:25 pm
Forum: Experimental Details
Topic: Pseudo Reaction
Replies: 1
Views: 355

Pseudo Reaction

Why is it that you are allowed to exclude one of the species when finding the order of that species?
Mon Mar 11, 2019 7:20 pm
Forum: Experimental Details
Topic: Fast vs Slow
Replies: 2
Views: 320

Fast vs Slow

How do you know which reaction is fast or slow?
Mon Mar 11, 2019 7:18 pm
Forum: Experimental Details
Topic: Dimerization
Replies: 2
Views: 317

Dimerization

In class, Dr. Lavelle mentioned dimerization. What is this?
Sun Mar 03, 2019 3:11 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: standard cell potential
Replies: 2
Views: 110

Re: standard cell potential

You just flip the sign.
Sat Mar 02, 2019 10:56 pm
Forum: Balancing Redox Reactions
Topic: d from 14.13
Replies: 2
Views: 149

Re: d from 14.13

It depends on where the electrons are. The Au3+ will have electrons to reduce down to Au+, while Au+ will reduce to Au. The electrons will cancel to make the original equation.
Sat Mar 02, 2019 10:53 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E vs E naught
Replies: 5
Views: 196

Re: E vs E naught

E naught means it is in standard conditions.
Sun Feb 24, 2019 5:22 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Ecell
Replies: 13
Views: 417

Re: Ecell

You would add the potential difference of the two half-reactions, keeping in mind that you may flip one-half reaction to cancel out the electrons.
Sat Feb 23, 2019 8:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams (Electrodes)
Replies: 1
Views: 89

Re: Cell Diagrams (Electrodes)

We would typically use electrodes like platinum if species aren't a conducting metal. For example, H2+Cl2=>HCl, we would use platinum electrodes because both hydrogen and chlorine are nonmetals.
Sat Feb 23, 2019 8:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6th Edition 14.15
Replies: 1
Views: 91

Re: 6th Edition 14.15

In the back of the book, there is a table full of potential difference for reactions. I would use that to determine what reactions took place. Then balance it to find the potential difference.
Sun Feb 17, 2019 7:00 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gases
Replies: 3
Views: 113

Gases

Do gases have a - delta G value because they are typically spontaneous?
Sun Feb 17, 2019 6:59 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneity
Replies: 4
Views: 221

Spontaneity

How does G relate to a reaction being spontaneous?
Sun Feb 17, 2019 6:55 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G=0
Replies: 1
Views: 66

Delta G=0

Why is delta G equal to 0 at constant temperature and pressure?
Sat Feb 09, 2019 8:06 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: When n is not given
Replies: 3
Views: 146

Re: When n is not given

If it states ideal gas, then yes it is safe to assume.
Fri Feb 08, 2019 6:03 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 4F.11
Replies: 1
Views: 121

Re: 4F.11

Since it is an ideal condition, it is implied that it is 1 mole.
Fri Feb 08, 2019 6:01 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Temperature and Entropy
Replies: 1
Views: 87

Re: Temperature and Entropy

When temperature increases it is implied there is a change in temperature. The formula only accounts for constant temperature. Therefore we can't use the equation for a change in temperature. We would need the equation of nCln(t2/t1) for the change of temperature.
Sun Feb 03, 2019 9:08 pm
Forum: Calculating Work of Expansion
Topic: Bond Formation
Replies: 3
Views: 140

Re: Bond Formation

Forming a bond is exothermic and breaking a bond is endothermic.
Sun Feb 03, 2019 7:29 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 1 Solutions
Replies: 4
Views: 238

Re: Test 1 Solutions

From last quarter, there weren't any solutions for tests. However it could be possible it be on Lavelle's webpage.
Sun Feb 03, 2019 7:28 pm
Forum: Ideal Gases
Topic: Different Pressure Definition
Replies: 3
Views: 300

Re: Different Pressure Definition

The SI unit is atm, but bar unit is more accurate. You could use J/L to find energy.
Sun Jan 27, 2019 4:08 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy of Diatomic Molecules
Replies: 1
Views: 69

Enthalpy of Diatomic Molecules

Is the reason for diatomic molecules enthalpy being 0 because that is the average for all the diatomic molecules or is it a different reason?
Sun Jan 27, 2019 4:03 pm
Forum: Ideal Gases
Topic: SI Units
Replies: 5
Views: 388

SI Units

What is the SI unit for pressure?
Sun Jan 27, 2019 3:58 pm
Forum: Calculating Work of Expansion
Topic: Irreversible vs. Reversible Expansion
Replies: 2
Views: 120

Irreversible vs. Reversible Expansion

How are we able to tell if an expansion is irreversible or not?
Sun Jan 20, 2019 6:26 pm
Forum: Conjugate Acids & Bases
Topic: Writing equations
Replies: 3
Views: 453

Re: Writing equations

If we were to look at the example of whether NH3 is a base, it would be easier to rely on the Lewis structure. We see that NH3 has a lone pair, this can make a bond with one of the Hydrogens of water and create a hydroxide concentration. All in all, when in doubt make the lewis dot structure.
Sun Jan 20, 2019 6:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Is it an acid or a base?
Replies: 8
Views: 313

Re: Is it an acid or a base?

We can tell if it donates or accepts a proton by the manner it dissociates. For example, if we were given the salt NH3Cl we would decide this is a base due to the fact that its reaction with water would produce a hydroxide concentration. I find it easier to tell if you add water to it and see whethe...
Sun Jan 20, 2019 6:13 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 12.69 6th edition AlCl3 equation
Replies: 1
Views: 32

Re: 12.69 6th edition AlCl3 equation

You wouldn't include chlorine since it would act as a spectator ion. Also HCl is a strong acid that dissociates completely so really you're solving for H+.
Sun Jan 13, 2019 2:40 pm
Forum: Administrative Questions and Class Announcements
Topic: HW 2 Due Date
Replies: 4
Views: 214

Re: HW 2 Due Date

I think it is due on our discussion.
Sun Jan 13, 2019 12:37 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 11.33
Replies: 1
Views: 69

Re: 11.33

You first convert every mmol to mol. This would be used to find concentration as it is Qc. Then, divide each by .5L because you are finding molarity. Then you make your ratio of products over reactants. You would get [SO3]^2/([SO2]^2[O2]). You input all your values and that is your answer.
Sun Jan 13, 2019 11:26 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Using variables in ICE tables
Replies: 2
Views: 86

Re: Using variables in ICE tables

It's much easier cause x can be anything thus it is used to define the change in molarity. It also makes things easier in the algebraic sense. Then we put whatever coefficient in front of x to display the conservation of matter. For example, if 1 reactant produced 2 product we would have -x and +2x ...
Sat Dec 08, 2018 1:10 am
Forum: Properties of Light
Topic: Electromagnetic Radiation and Speed
Replies: 2
Views: 392

Re: Electromagnetic Radiation and Speed

If we talking about DeBroigles wavelength, it is because velocity and wavelength are inversely proportionate. A bigger wavelength means smaller speed while a smaller wavelength means bigger speed. If we are talking about the wavelength in reference to light, the speed is always the same since it is ...
Sat Dec 08, 2018 1:05 am
Forum: Dipole Moments
Topic: churro 38
Replies: 3
Views: 342

Re: churro 38

Due to the fact it has a higher molar mass it is a bigger molecule, thus it requires more energy.
Sat Dec 08, 2018 1:03 am
Forum: Lewis Acids & Bases
Topic: H-
Replies: 3
Views: 111

Re: H-

It's a bronsted base because it accepts a proton.
Sun Dec 02, 2018 8:28 pm
Forum: Naming
Topic: water
Replies: 2
Views: 116

Re: water

It doesn't really matter as the implication is the same yet it depends on the location. You would want the lewis dot structure to agree with the model. For example you would typically put the line to Oxygen of H2O since Oxygen is able to be bonded.
Sun Dec 02, 2018 8:26 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy and Electron Affinity Trend Exceptions
Replies: 2
Views: 428

Re: Ionization Energy and Electron Affinity Trend Exceptions

Typically ionization energy decreases as you go down the and increases as you go right. This is true for electron affinity.
Sun Dec 02, 2018 8:21 pm
Forum: Hybridization
Topic: Double and Triple Bonds
Replies: 17
Views: 3297

Re: Double and Triple Bonds

It would if you consider Carbon for example that it changed from sp3 to sp2 when it is double bonded. It is dependent on the number of bonding regions.
Sun Nov 25, 2018 4:12 pm
Forum: Hybridization
Topic: Hybridization and molecular shape
Replies: 3
Views: 128

Re: Hybridization and molecular shape

Bonds don't affect the shape, they just affect the rotation.
Sun Nov 25, 2018 4:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2.45
Replies: 2
Views: 83

Re: 2.45

That is because C has 3 bonding regions so it is sp2 and since there is a triple bond it is a sigma bond with 2 bonds.
Sun Nov 25, 2018 4:00 pm
Forum: Hybridization
Topic: Bonds
Replies: 2
Views: 136

Re: Bonds

Whenever there is a single bond, it is just a sigma bond. Whenever it is a double bond, there is a sigma bond and a double bond. Whenever it is a triple bond, there is a sigma bond with 2 pi bonds.
Sun Nov 18, 2018 9:53 pm
Forum: Hybridization
Topic: Promotion
Replies: 3
Views: 130

Promotion

What is electron promotion and how can we tell if electron promotion took place?
Sat Nov 17, 2018 6:28 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Energy of Intermolecular Forces
Replies: 6
Views: 273

Re: Energy of Intermolecular Forces

They are all negative because it is taking energy from the system to form bonds. This takes away energy thus a negative energy.
Sat Nov 17, 2018 6:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR w/ more than 1 central atom
Replies: 2
Views: 480

Re: VSEPR w/ more than 1 central atom

I think we are supposed to say the VSEPR model per atom. For example C2H4, both labels would be trigonal planar. If it was C2H3O-, then we would label the C's as C1 and C2. C1 would be trigonal planar while C2 would be tetrahedral.
Sun Nov 11, 2018 1:30 pm
Forum: Dipole Moments
Topic: Bonding
Replies: 3
Views: 139

Re: Bonding

I think he was referring to the strength of the bonding. In terms of strength they are relatively similar.
Sun Nov 11, 2018 1:28 pm
Forum: Dipole Moments
Topic: Interaction potential energy, relation to distance
Replies: 2
Views: 134

Re: Interaction potential energy, relation to distance

It means the distance would affect the strength of the energy. Since r is to the 6th power it makes energy very dependable to distance.
Sun Nov 11, 2018 1:27 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 3
Views: 151

Re: Resonance Structures

I think it is possible but we would have to check the formal charge and if the number of electrons matches with the chemical formula.
Sun Nov 04, 2018 12:03 am
Forum: Ionic & Covalent Bonds
Topic: Homework Problem 3.19
Replies: 2
Views: 132

Re: Homework Problem 3.19

We use the electron configuration. We would adjust this due to the charge. Then we draw the spins of the electrons.
Sat Nov 03, 2018 11:58 pm
Forum: General Science Questions
Topic: Midterm
Replies: 3
Views: 208

Re: Midterm

I'm pretty sure the difficulty is the same or if not it is testing us on the concepts.
Sat Nov 03, 2018 11:53 pm
Forum: Octet Exceptions
Topic: Copper
Replies: 10
Views: 380

Re: Copper

It is more stable to be in 3d10 in comparison to 3d9 as it is closer to the full shell.
Sat Oct 27, 2018 10:18 pm
Forum: Formal Charge and Oxidation Numbers
Topic: hw problem 3.51 6th edition
Replies: 2
Views: 114

Re: hw problem 3.51 6th edition

The formal charge is what you use to find the lowest energy in terms of resonant structures. The formal charge closest to 0 is often lowest energy. The best example can be seen in pg. 83.
Sat Oct 27, 2018 2:38 pm
Forum: Ionic & Covalent Bonds
Topic: Lowest Energy
Replies: 4
Views: 126

Re: Lowest Energy

It just means that it is at it's most stable state.
Mon Oct 22, 2018 7:26 pm
Forum: Photoelectric Effect
Topic: 6th Edition 1.33 (c)
Replies: 1
Views: 136

Re: 6th Edition 1.33 (c)

In the previous question, as in b, we found the threshold energy. What we currently have is the threshold energy, the mass of the electron (which is implied when it states electron), the velocity of the electron (which we converted to m/s). With the mass and velocity of the electron, we can find the...
Sun Oct 21, 2018 1:10 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenbergy Uncertainty Equation
Replies: 3
Views: 171

Heisenbergy Uncertainty Equation

In the book (6th edition) it says the equation is momentum*postion=h/2pi. I thought it was over 4 pi. Is this a typo or is it really over 2pi,
Sun Oct 21, 2018 12:58 pm
Forum: Properties of Light
Topic: 7th Edition, Quantum Theory, #1.B.15
Replies: 2
Views: 138

Re: 7th Edition, Quantum Theory, #1.B.15

Did they state velocity of the electron? If so you would use the equation h/mv=wavelength. M is the mass of electron.
Sun Oct 21, 2018 12:55 pm
Forum: Photoelectric Effect
Topic: Help with 33 (6th edition) [ENDORSED]
Replies: 3
Views: 233

Re: Help with 33 (6th edition)[ENDORSED]

The first step is to convert it to m/s. Then you would use the equation lambda (wavelength) = h/(mass of the electron*velocity). This would give your answer.
Sat Oct 13, 2018 1:27 pm
Forum: Limiting Reactant Calculations
Topic: Test 1
Replies: 5
Views: 362

Re: Test 1

I remember Lavelle saying that he won't take off too many points if you don't have the right significant figures. That implies he'll give partial credit.
Sat Oct 13, 2018 1:23 pm
Forum: Properties of Light
Topic: Properties of Light - variables?
Replies: 2
Views: 89

Re: Properties of Light - variables?

If you are asking what is the variable that is the speed of light that would be c which is 3E8. If you asking the formula it would be c= wavelength(meters) times frequency in Hz.
Thu Oct 11, 2018 12:05 am
Forum: SI Units, Unit Conversions
Topic: Should Significant Figures be affected by constants?
Replies: 10
Views: 382

Re: Should Significant Figures be affected by constants?

It shouldn't affect the constants since they are typically rounded off. Typically, significant figures are for the shortest amount of digits.
Wed Oct 03, 2018 5:22 pm
Forum: Molarity, Solutions, Dilutions
Topic: E.9 on homework
Replies: 4
Views: 156

Re: E.9 on homework

Since it says hepta in front of hydrate, where I believe in Greek hepta means 7, we put 7 in front of H20.
Wed Oct 03, 2018 5:19 pm
Forum: Limiting Reactant Calculations
Topic: Limiting reactants step 4
Replies: 2
Views: 330

Re: Limiting reactants step 4

When finding the molar mass of a compound you don't need the coefficient because you add the masses of all atoms in the compound. If you are talking about finding grams or the mass, you would then need the coefficient for the mole to mole ratio.
Wed Oct 03, 2018 5:07 pm
Forum: Limiting Reactant Calculations
Topic: Finding the Limiting Reactant
Replies: 2
Views: 139

Re: Finding the Limiting Reactant

Normally there would be a limiting reactant. However, if there was the case you just described, it would be interchangeable since it none of the reactants would limit each other.

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