Search found 43 matches
- Wed Mar 09, 2016 1:03 pm
- Forum: *Alcohols
- Topic: Numbers within the name?
- Replies: 1
- Views: 483
Re: Numbers within the name?
It is redundant but you definitely won't lose points for it! But when you are reading something and it doesn't have a number, you can reasonably assume that it is 1.
- Mon Mar 07, 2016 1:47 pm
- Forum: Calculating Work of Expansion
- Topic: Work formulas
- Replies: 3
- Views: 767
Re: Work formulas
Yes. They have different formulas stated on our equation sheet.
- Mon Mar 07, 2016 1:46 pm
- Forum: Calculating Work of Expansion
- Topic: 2011 Midterm Q1B
- Replies: 2
- Views: 637
Re: 2011 Midterm Q1B
We'll work for irreversible processes is P x delta V. P delta V is also equal to delta nRT. You can calculate it from there.
- Wed Mar 02, 2016 7:04 pm
- Forum: *Electrophiles
- Topic: Equal sign with a line through it
- Replies: 4
- Views: 2204
Re: Equal sign with a line through it
it means does not equal
- Wed Feb 24, 2016 7:01 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: half lives
- Replies: 4
- Views: 13567
Re: half lives
Because .25=1/4. 1/4=(1/2)^2. Therefore, to find the "fourth life" you just multiply the half life by 2.
- Wed Feb 24, 2016 7:00 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Rate Laws
- Replies: 2
- Views: 629
Re: Rate Laws
No. there are only quantitative ways.
- Thu Feb 11, 2016 12:10 pm
- Forum: Balancing Redox Reactions
- Topic: Writing Skeletal Equations
- Replies: 4
- Views: 1153
Re: Writing Skeletal Equations
Because BrO3 is the term corresponding with Br.
- Thu Feb 11, 2016 12:07 pm
- Forum: Balancing Redox Reactions
- Topic: pairs of redox couples
- Replies: 3
- Views: 796
Re: pairs of redox couples
Basically, your reduction (cathode) equation will be the one that has the more positive cell potential. Therefore, your anode will be the one that is less positive. Since Ecell= Ecathode - Eanode, your Ecell would be positive, making the reaction spontaneous and favorable.
- Sun Feb 07, 2016 11:33 pm
- Forum: Calculating Work of Expansion
- Topic: Usage of PV=nRT
- Replies: 2
- Views: 764
Re: Usage of PV=nRT
You can replace it! Try to figure out which equation to use based on the equation that they give you.
- Sun Feb 07, 2016 11:31 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electric Potential
- Replies: 2
- Views: 554
Re: Electric Potential
They mean the same.
- Sun Feb 07, 2016 11:30 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Quiz 1
- Replies: 2
- Views: 701
Re: Quiz 1
Well, you need to change 1 kg of steam at 180 degrees to an ice cube at 0 degrees. So, it is the heat it takes to lower the temp to 100 degrees, then the heat it takes to turn it to water, then the heat it takes to lower the temperature of water to 0 degrees, then the heat it takes to turn it to ice...
- Thu Jan 28, 2016 11:46 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Reversible?
- Replies: 3
- Views: 737
Re: Reversible?
Most of the time they state it in the question. If it is reversible, work is usually -nRTln(V2/V1). If it is not reversible, work is normally -PdV.
- Thu Jan 28, 2016 11:44 am
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Perfect Crystals
- Replies: 2
- Views: 541
Re: Perfect Crystals
It will be stated as "perfect" i would assume. Since S=KlnW, W would be 1 in a perfect system and S would be 0.
- Thu Jan 28, 2016 11:15 am
- Forum: Calculating Work of Expansion
- Topic: Work on a system vs. work by a system
- Replies: 2
- Views: 1519
Re: Work on a system vs. work by a system
Imagine a container with a piston on top. Work done on the system would be if someone pushed the piston down. This would be Positive Work. Work done by the system would be if the piston pushed up into the surrounding environment, increasing the volume of the system. This would be Negative Work.
- Mon Jan 25, 2016 11:07 am
- Forum: Calculating Work of Expansion
- Topic: Irreversible and reversible heat transfer
- Replies: 3
- Views: 700
Re: Irreversible and reversible heat transfer
Usually irreversible processes occur under constant pressure and irreversible processes do not. Irreversible processes do more work.
- Wed Jan 20, 2016 12:13 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: State function vs not state function
- Replies: 2
- Views: 650
Re: State function vs not state function
A state function does not depend on the path taken. For example, work is not a state function because the amount of work done does depend on the path that you take, not just the initial and final values.
- Wed Jan 20, 2016 12:11 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Reversible systems clarification
- Replies: 2
- Views: 667
Re: Reversible systems clarification
If you graph a reversible process and the irreversible process changing the same amount of volume, you will clearly be able to see that the reversible process does more work based on the area under the curve.
- Wed Jan 20, 2016 12:09 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Closed adiabatic system
- Replies: 2
- Views: 616
Re: Closed adiabatic system
No. In isolated systems, delta U= 0 because no heat can be transferred from the system and the environment and no work can be done on the system. q=0 and w=0
- Thu Jan 14, 2016 8:04 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Work in Reversible Process vs Work in Irreversible Process
- Replies: 3
- Views: 986
Re: Work in Reversible Process vs Work in Irreversible Proce
If you graph the two, it is pretty easy to see that a reversible process does more work. The area under the curve is greater.
- Mon Jan 11, 2016 9:39 am
- Forum: Phase Changes & Related Calculations
- Topic: Isolated systems
- Replies: 3
- Views: 666
Re: Isolated systems
Because it completely isolates it from it's outside environment so that there is no interaction.
- Mon Jan 11, 2016 9:37 am
- Forum: Phase Changes & Related Calculations
- Topic: Phase Changes- Melting/Boiling
- Replies: 4
- Views: 867
Re: Phase Changes- Melting/Boiling
The temperature remains constant during a phase change because the heat is being used to break the bonds, not raise the temperature. This is why on a temperature curve, you can tell a phase change is happening when the line plateaus.
- Mon Jan 11, 2016 9:35 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law
- Replies: 3
- Views: 686
Re: Hess's Law
Yes, they would have to be on opposite sides.
- Wed Dec 02, 2015 6:56 pm
- Forum: Dipole Moments
- Topic: POLAR/NON POLAR
- Replies: 2
- Views: 714
Re: POLAR/NON POLAR
I find that the easiest way is to draw them out to see if they cancel. Also a general rule of thumb is that if the atoms are symmetric around a central atom, then the dipole moments do cancel (such as in a trigonal planar model). Also, cis is if the dipoles are on the same side of the molecule. Tran...
- Wed Dec 02, 2015 6:53 pm
- Forum: Electronegativity
- Topic: What makes a bond ionic? What is proper notation for charge?
- Replies: 2
- Views: 862
Re: What makes a bond ionic? What is proper notation for cha
A bond is ionic if it has a charge. There is a cation and an anion involved, where the cation loses an electron and becomes positively charged, and the anion gains one and becomes negatively charged. You put brackets and then a superscript to the right.
- Wed Dec 02, 2015 6:50 pm
- Forum: Electronegativity
- Topic: Ionization energy vs electronegativity vs electron affinity
- Replies: 7
- Views: 3801
Re: Ionization energy vs electronegativity vs electron affin
Question: Can you explain the difference between ionization energy, electronegativity and electron affinity? I get them all confused, especially the last two listed. Electronegativity is how strongly an atom attracts a pair of electrons (a stronger pull). Ionization energy is the amount of energy ne...
- Wed Dec 02, 2015 6:48 pm
- Forum: Electronegativity
- Topic: Periodic Trends
- Replies: 2
- Views: 710
Re: Periodic Trends
I feel like electronegativity is the most essential one. It increases as you go up and to the right.
- Wed Dec 02, 2015 6:46 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing equations
- Replies: 3
- Views: 1067
Re: Balancing equations
They are both correct. But always go with the whole numbers. Especially if its a problem involving chemical equilibrium because if you didn't use whole numbers, your K value would be incorrect.
- Wed Dec 02, 2015 6:45 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing Equations Shortcut
- Replies: 2
- Views: 5373
Re: Balancing Equations Shortcut
Start with one element and balance it by placing coefficients. Then keep going until they all work out. Make sure that your coefficients are the smallest possible whole numbers. Ex. if you ever have 2, 2, and 4, as your coefficients, change them to 1, 1, and 2.
- Wed Dec 02, 2015 6:38 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Delta x
- Replies: 4
- Views: 2602
Re: Delta x
Delta x is the uncertainty in position. So if they say that an electron is in its nuclear diameter, the diameter would be your uncertainty in position because it could be anywhere in this location. Or if they say that the location is 2.0m +/- 1, your uncertainty would be 2 because it could be betwee...
- Wed Dec 02, 2015 6:35 pm
- Forum: Properties of Light
- Topic: Kinetic Energy 1.23 c
- Replies: 5
- Views: 1007
Re: Kinetic Energy 1.23 c
Well, Energy or hv= Work needed to remove an electron + the Kinetic Energy. So you plug in the given information and find out what you need.
- Wed Dec 02, 2015 6:32 pm
- Forum: Properties of Light
- Topic: De Brogile's Equation [ENDORSED]
- Replies: 3
- Views: 912
Re: De Brogile's Equation [ENDORSED]
Yes. You always need to keep the units in mind. If not, the equations do not apply.
- Wed Dec 02, 2015 6:32 pm
- Forum: Properties of Light
- Topic: % Yield
- Replies: 5
- Views: 1519
Re: % Yield
Just remember this simple formula: actual/theoretical * 100
- Wed Dec 02, 2015 6:31 pm
- Forum: Properties of Light
- Topic: Question: Wave Model vs. Photon Model of Light
- Replies: 7
- Views: 3502
Re: Question: Wave Model vs. Photon Model of Light
If light acted as a wave in the photoelectric effect, then increasing the intensity would increase the amplitude and therefore cause electrons to be emitted. But none were. This shows that it does not act as a wave, but instead as a particle. The only way they could emit electrons was when they used...
- Wed Dec 02, 2015 6:29 pm
- Forum: Properties of Light
- Topic: Difference between line spectrum and line emission spectrum?
- Replies: 2
- Views: 644
Re: Difference between line spectrum and line emission spect
He said that all these different names pretty much refer to the same thing.
- Wed Dec 02, 2015 6:28 pm
- Forum: Properties of Light
- Topic: Speed
- Replies: 3
- Views: 744
Re: Speed
It doesn't matter much. Just use the speed provided on the test.
- Wed Dec 02, 2015 6:25 pm
- Forum: Properties of Light
- Topic: Shorter vs Longer Wavelength
- Replies: 6
- Views: 2709
Re: Shorter vs Longer Wavelength
Shorter wavelengths have higher frequencies. E= planks constant times frequency. Higher frequency will give you a higher energy.
- Wed Dec 02, 2015 6:24 pm
- Forum: Properties of Light
- Topic: Heisenberg's Equation
- Replies: 3
- Views: 919
Re: Heisenberg's Equation
It is an uncertainty equation and therefore only gives you the uncertainty of either position and/or velocity.
- Wed Dec 02, 2015 6:23 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Bonding vs Antibonding
- Replies: 2
- Views: 2032
Re: Bonding vs Antibonding
If two orbitals are in phase, then they are bonding. These bonding orbitals will stabilize the molecule. If two orbitals are out of phase, then they are anti bonding, and will not stabilize the molecule.
- Wed Dec 02, 2015 6:19 pm
- Forum: Lewis Acids & Bases
- Topic: Trends on the Periodic Table with Acids
- Replies: 2
- Views: 789
Re: Trends on the Periodic Table with Acids
Basically, the weaker the A-H bond, the easier it is for H20 to remove the H+. So weaker bonds are more acidic.
- Wed Dec 02, 2015 6:13 pm
- Forum: SI Units, Unit Conversions
- Topic: Percentages Sig Figs? [ENDORSED]
- Replies: 5
- Views: 29871
Re: Percentages Sig Figs? [ENDORSED]
You would just put as many sigfigs as are provided in the question.
- Wed Dec 02, 2015 6:11 pm
- Forum: *Titrations & Titration Calculations
- Topic: Titration
- Replies: 1
- Views: 534
Re: Titration
pOH is -log of the concentration of OH. You use either depending on the information you are given.
- Fri Oct 02, 2015 4:15 pm
- Forum: Significant Figures
- Topic: All students read this sig fig post [ENDORSED]
- Replies: 170
- Views: 33511
Re: All students read this sig fig post [ENDORSED]
Jordanmjones13 wrote:Do you know if the problems will specifically tell us how many significant figures to use?
Evamae Bayudan 1B wrote:Will we be penalized for putting extra significant figures?
No. Your answer should have the same number of sigfigs as the number in the question with the lowest number of sigfigs
- Fri Oct 02, 2015 4:13 pm
- Forum: Significant Figures
- Topic: All students read this sig fig post [ENDORSED]
- Replies: 170
- Views: 33511
Re: All students read this sig fig post [ENDORSED]
Evamae Bayudan 1B wrote:Will we be penalized for putting extra significant figures?
Yes. You'll lose a point because you are making it seem like you have more accuracy than you actually do.