## Search found 43 matches

Wed Mar 09, 2016 1:03 pm
Forum: *Alcohols
Topic: Numbers within the name?
Replies: 1
Views: 320

### 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: 526

### 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: 441

### 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: 1302

### 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: 11116

### 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: 435

### 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: 860

### 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: 590

### 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: 565

### 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: 364

### 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: 473

### 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: 507

### 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: 382

### 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: 691

### 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: 493

### 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: 457

### 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: 491

### 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
Replies: 2
Views: 408

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: 728

### 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: 458

### 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: 601

### 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: 515

### 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: 542

### 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: 673

### 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: 2530

### 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: 522

### 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: 881

### 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: 3604

### 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: 1591

### 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: 743

### 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: 703

### 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: 1067

### 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: 2350

### 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: 505

### 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: 567

### 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: 1702

### 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: 681

### 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: 510

### 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: 564

### 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: 16691

### 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: 367

### 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: 131
Views: 17182

### 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: 131
Views: 17182

### 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.