Search found 60 matches
- Mon Mar 11, 2019 7:34 pm
- Forum: General Rate Laws
- Topic: Unique Rate Law
- Replies: 4
- Views: 486
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: 280
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: 422
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: 713
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: 7
- Views: 1233
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: 797
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: 300
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: 374
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: 715
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: 1505
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: 241
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: 218
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: 397
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: 538
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: 200
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: 386
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: 270
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: 266
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: 365
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: 531
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: 542
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: 190
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: 679
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: 264
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: 716
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: 716
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: 87
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: 447
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: 116
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: 259
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: 676
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: 645
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: 329
Re: H-
It's a bronsted base because it accepts a proton.
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: 712
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: 4349
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: 372
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: 230
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: 342
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: 326
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: 948
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: 1211
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: 318
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: 288
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: 378
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: 296
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: 345
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: 993
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: 233
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: 349
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: 275
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: 387
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: 330
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: 411
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: 649
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: 292
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: 991
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: 296
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: 1145
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: 298
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.