Search found 104 matches
- Fri Mar 13, 2020 11:50 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student [ENDORSED]
- Replies: 297
- Views: 425500
Re: Advice from a Medical Student [ENDORSED]
Thank you so much! This helped a lot!
- Fri Mar 13, 2020 11:49 pm
- Forum: Student Social/Study Group
- Topic: Final Jitters
- Replies: 457
- Views: 381871
Re: Final Jitters
maybe focus on your breathing and trying to relax? listening to music could also help you calm down a bit
- Fri Mar 13, 2020 11:43 pm
- Forum: Student Social/Study Group
- Topic: final?
- Replies: 7
- Views: 691
Re: final?
He said he'll update us on Saturday!
- Fri Mar 13, 2020 11:42 pm
- Forum: Administrative Questions and Class Announcements
- Topic: "Open Book" Final?
- Replies: 30
- Views: 2124
Re: "Open Book" Final?
I'm assuming your textbook and any lecture notes you took
- Fri Mar 13, 2020 11:40 pm
- Forum: Administrative Questions and Class Announcements
- Topic: "Open Book" Final?
- Replies: 30
- Views: 2124
Re: "Open Book" Final?
Does anyone know how the final is going to be given? Will it be a pdf that we have to print out and then take pictures of our answers or is it like through that respondus webcam thingie? So far all he has said is that it's going to be taken online, but we don't need to use any other apps/software l...
- Fri Mar 13, 2020 11:38 pm
- Forum: Administrative Questions and Class Announcements
- Topic: "Open Book" Final?
- Replies: 30
- Views: 2124
Re: "Open Book" Final?
TimVintsDis4L wrote:Mariah wrote:Any word on how long it will be ?
He mentioned that it was going to be pretty short and simple so I would assume no more than 1.5 hours, so half of what the actual final would have been like.
His email said he was debating between 3 or 4 hours.
- Fri Mar 13, 2020 11:36 pm
- Forum: Administrative Questions and Class Announcements
- Topic: take home FINAL DEADLINE
- Replies: 15
- Views: 1134
Re: take home FINAL DEADLINE
He said it was going to be taken the same time he has scheduled, but he's still deciding on whether or not the exam is going to be 3 or 4 hours.
- Sun Mar 08, 2020 9:40 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: K
- Replies: 11
- Views: 670
Re: K
K is dependent on temperature and activation energy I believe
- Sun Mar 08, 2020 9:39 pm
- Forum: Administrative Questions and Class Announcements
- Topic: TesT 2
- Replies: 3
- Views: 286
Re: TesT 2
We usually get them back the following week so pretty sure you'll get them back week 10
- Sun Mar 08, 2020 9:38 pm
- Forum: General Science Questions
- Topic: Who makes the Final
- Replies: 23
- Views: 1493
Re: Who makes the Final
Cindy Adiwidjaja 1B wrote:Do you guys know if the TAs made Test 2, because I felt like it was formatted much differently than the other tests.
I think the TAs made the test and Lavelle makes the midterm and final
- Sun Mar 08, 2020 9:36 pm
- Forum: General Science Questions
- Topic: Test 2 Grades [ENDORSED]
- Replies: 23
- Views: 1639
Re: Test 2 Grades [ENDORSED]
Probably this weeks discussion
- Sun Mar 08, 2020 9:36 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Study Advice
- Replies: 73
- Views: 7202
Re: Study Advice
review the notes and try to do all of the homework/textbook problems
- Sun Mar 01, 2020 5:24 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagrams
- Replies: 6
- Views: 456
Re: Cell Diagrams
Osvaldo SanchezF -1H wrote:We might be asked to do this but in the form of s|g|aq||aq|g|s and not an actual picture.
I agree, I think you should memorize how to write it in this form.
- Sun Mar 01, 2020 5:23 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: salt bridge
- Replies: 11
- Views: 689
Re: salt bridge
To maintain the charge balance between the anode and cathode
- Sun Mar 01, 2020 5:20 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: cell potential
- Replies: 15
- Views: 830
Re: cell potential
When E is positive, delta G will be negative. This would mean that the reaction will be spontaneous. However, when E is negative, delta G will be positive. This would mean that the reaction will be non-spontaneous.
- Sun Mar 01, 2020 5:18 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Flipping the sign
- Replies: 10
- Views: 662
Re: Flipping the sign
E is typically given for reduction reactions. When you're expected to find the E of an oxidation reaction, you're supposed to flip the sign for the oxidation half-reaction
- Sun Mar 01, 2020 4:46 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: how can you tell
- Replies: 11
- Views: 800
Re: how can you tell
kinetically controlled reactions are usually short while thermo controlled reactions are long.
- Mon Feb 24, 2020 12:37 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: G(not) and G
- Replies: 15
- Views: 750
Re: G(not) and G
G(not) is at standard Gibbs free energy, thus it is under standard conditions, unlike G.
- Sun Feb 23, 2020 11:37 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: U vs H
- Replies: 15
- Views: 1268
Re: U vs H
Delta U represents the change in internal energy while delta H represents the change in enthalpy.
- Sun Feb 23, 2020 11:29 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Test 2
- Replies: 13
- Views: 702
Re: Test 2
It should be on the rest of thermodynamics (second page) and electrochemistry.
- Sun Feb 23, 2020 10:32 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: | divider in cell diagram
- Replies: 5
- Views: 358
Re: | divider in cell diagram
Sydney Pell 2E wrote:If the two were in different phases, would there then need to be a 'I' separating them?
I think you'd need to separate them if they were in different phases.
- Sun Feb 23, 2020 10:31 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation
- Replies: 4
- Views: 286
Re: Nernst Equation
We use the equation to find the cell reduction potential when the product and reactant concentrations are known.
- Sun Feb 16, 2020 11:20 pm
- Forum: Phase Changes & Related Calculations
- Topic: Negative Work
- Replies: 18
- Views: 1497
Re: Negative Work
When a system is doing the work, w is negative (ex. expansion), but when work is being done on a system, w is positive (ex. compression).
- Sun Feb 16, 2020 11:16 pm
- Forum: Balancing Redox Reactions
- Topic: oxidation vs reduction
- Replies: 19
- Views: 1028
Re: oxidation vs reduction
Oxidation occurs when a molecule loses an electron. Reduction occurs when it gains an electron.
- Sun Feb 16, 2020 11:16 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: ∆G = ∆Gº + RT lnQ
- Replies: 12
- Views: 2635
Re: ∆G = ∆Gº + RT lnQ
∆G= the change of Gibbs free energy for a system while ∆G°= the change of Gibbs free energy for a system under standard conditions
- Sun Feb 16, 2020 11:12 pm
- Forum: Balancing Redox Reactions
- Topic: Memorizing charges
- Replies: 11
- Views: 745
Re: Memorizing charges
Memorizing the common ones should be fine
- Sun Feb 16, 2020 11:11 pm
- Forum: Van't Hoff Equation
- Topic: Significance of Van't Hoff Equation
- Replies: 8
- Views: 608
Re: Significance of Van't Hoff Equation
Jacob Puchalski 1G wrote:I think the point was to relate K to the temperature? I might be wrong
I think it's the change in K and the change in temperature??
- Sun Feb 09, 2020 9:07 pm
- Forum: Calculating Work of Expansion
- Topic: Constant pressure
- Replies: 2
- Views: 97
Constant pressure
Will constant pressure be told to us or do we have to assume it for things outside?
- Sun Feb 09, 2020 9:03 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat capacity
- Replies: 2
- Views: 98
Heat capacity
How is heat capacity a state function? What does that mean for heat capacities.
- Sun Feb 09, 2020 8:59 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Pressure
- Replies: 2
- Views: 152
Re: Pressure
If the pressure change is caused by a change in volume then yes otherwise I don’t think so
- Sun Feb 09, 2020 8:58 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Difference between Cv and Cp?
- Replies: 8
- Views: 530
Re: Difference between Cv and Cp?
Cv is for constant volume and Cp is constant pressure. I don’t think they’re the same value.
- Sun Feb 09, 2020 8:56 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Pizza Rolls REVIEW Session DOWNLOAD HERE
- Replies: 67
- Views: 5868
Re: Pizza Rolls REVIEW Session DOWNLOAD HERE
DesireBrown1J wrote:What was the little saying to remember the state functions other than entropy and enthalpy? The HUGS and TV one?
If you’re under Pressure and feeling Dense, all you want is to watch TV and get HUGS.
- Sun Feb 09, 2020 8:55 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Pizza Rolls REVIEW Session DOWNLOAD HERE
- Replies: 67
- Views: 5868
Re: Pizza Rolls REVIEW Session DOWNLOAD HERE
DesireBrown1J wrote:Why is delta H always q but q is not always delta H? What exactly does he mean by that?
DeltaH by definition is q at constant pressure. But if q is not at constant pressure then it is not deltaH.
- Fri Jan 31, 2020 12:49 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm
- Replies: 8
- Views: 384
Re: Midterm
905373636 wrote:Will it focus more on the new content than what we’ve already learned for Test 1 or just even distribution?
I'm not sure about distribution, but I'm pretty sure some of the material we were tested on for Test 1 will be on the midterm.
- Fri Jan 31, 2020 12:47 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: hess's law
- Replies: 13
- Views: 387
Re: hess's law
Yes, they need to be on opposite sides to cancel out. When the equal number of moles of the reactant and product you're looking at are on opposite sides, they balance out and therefore cancel.
- Fri Jan 31, 2020 12:40 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Closed vs isolated systems
- Replies: 24
- Views: 916
Re: Closed vs isolated systems
Closed systems are able to exchange energy, and therefore heat, with their surroundings. Isolated systems can't exchange energy with their surroundings.
- Fri Jan 31, 2020 12:32 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ideal Gas QUestions
- Replies: 8
- Views: 444
Re: Ideal Gas QUestions
yes, because the molecules will have less space to move around
- Fri Jan 31, 2020 12:29 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy Unit
- Replies: 6
- Views: 193
Re: Enthalpy Unit
The unit for ∆H is usually kJ/mol, but I think it would be kJ when you're given moles and expected to find the change in enthalpy.
- Fri Jan 24, 2020 5:57 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpy Accuracy
- Replies: 6
- Views: 145
Re: Bond Enthalpy Accuracy
I'm not sure but I think it has to do with the fact that the bond enthalpies of all molecules other than diatoms are averages. Since the averages are given and not the actual values, they aren't as accurate.
- Fri Jan 24, 2020 5:52 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Calculating Delta H
- Replies: 3
- Views: 81
Re: Calculating Delta H
He ended the lecture on method 3 today so we'll probably go over it in the next lecture.
- Fri Jan 24, 2020 5:47 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Q<K
- Replies: 11
- Views: 300
Re: Q<K
When Q<K, the forward reaction is favored because the concentrations/partial pressures of the products are too low compared to reactants for equilibrium. Therefore, the excess reactants would form more products in order to reach equilibrium.
- Fri Jan 24, 2020 4:21 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Calculating K
- Replies: 15
- Views: 778
Re: Calculating K
Make sure you balance all of your equations. Not doing so could cause you to end up with the wrong K value since your coefficients might be wrong.
- Fri Jan 24, 2020 4:18 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: pka
- Replies: 4
- Views: 291
Re: pka
No, strong acids would have a lower pka
- Fri Jan 17, 2020 4:56 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Solids and Equilibrium
- Replies: 9
- Views: 315
Re: Solids and Equilibrium
Neither of them affect the equilibrium or equilibrium constant because they're pure substances. Solids don't have a concentration, and liquids act as solvents and their concentrations don't change.
- Fri Jan 17, 2020 4:45 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE tables
- Replies: 5
- Views: 211
Re: ICE tables
you usually use ice tables when the initial concentration is given
- Fri Jan 17, 2020 4:28 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Value of Kw
- Replies: 6
- Views: 176
Re: Value of Kw
Yes, at 25 degrees celcius, Kw will always be equal to 1.0 x 10^-14
- Fri Jan 17, 2020 4:14 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: ICE table
- Replies: 11
- Views: 391
Re: ICE table
You use the ICE table for weak acids and bases (doesn't fully dissociate)
- Fri Jan 17, 2020 4:10 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Tips for Test
- Replies: 23
- Views: 1184
Re: Tips for Test
You should work on the practice homework problems and review your lecture notes. You could even work on problems together with your friends and go over what you guys need more help/clarification on.
- Thu Jan 09, 2020 10:38 pm
- Forum: Ideal Gases
- Topic: Understanding Q
- Replies: 13
- Views: 547
Re: Understanding Q
I understand the fact that you omit solids and liquids when calculating the equilibrium constant, but why? What's the logic behind it? Solids and liquids aren't included because they do not have a significant effect on the concentration. Lavelle also mentioned during lecture that solids do not have...
- Thu Jan 09, 2020 10:25 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Meaning of equilibrium constant
- Replies: 5
- Views: 252
Re: Meaning of equilibrium constant
neither the reactants nor the products are strongly favored
- Thu Jan 09, 2020 9:59 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K and Q Values
- Replies: 5
- Views: 214
Re: K and Q Values
No, the reverse reaction is favored because the concentration/partial pressure of the reactants is less than that of the products. Therefore, more reactants need to be produced so that the reaction can reach equilibrium. (Hope this is right and helpful!)
- Thu Jan 09, 2020 9:44 pm
- Forum: Ideal Gases
- Topic: Reaction Quotient (Q)
- Replies: 8
- Views: 338
Re: Reaction Quotient (Q)
When a reaction isn't at equilibrium, you would try to find the reaction quotient, Q, in order to determine which direction the reaction will favor. When Q<K, the FORWARD (goes toward products) reaction is favored because the concentrations/partial pressures of the products are too low compared to r...
- Thu Jan 09, 2020 8:53 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: solids and liquids
- Replies: 6
- Views: 227
Re: solids and liquids
Solids are not included in the equilibrium constant because they do not have a concentration. Liquids are also not included because they are in excess and their concentrations do not change (it stays constant throughout the reaction).
- Sun Dec 08, 2019 8:04 pm
- Forum: Hybridization
- Topic: Pi bond
- Replies: 10
- Views: 789
Re: Pi bond
Pi bonds are unhbyrdizied p orbitals and can also be d orbitals i think
- Sun Dec 08, 2019 8:03 pm
- Forum: General Science Questions
- Topic: Polarizbity
- Replies: 2
- Views: 473
Re: Polarizbity
If you are referring to the final, I think it asked about more polarizing, not polarizability. The above answer looks right.
- Sun Dec 08, 2019 8:00 pm
- Forum: Lewis Acids & Bases
- Topic: memorizing ligands
- Replies: 5
- Views: 483
Re: memorizing ligands
Guess we didnt really have to memorize it since there was no naming on the final...
- Sun Dec 08, 2019 7:59 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: vsepr formula
- Replies: 7
- Views: 626
Re: vsepr formula
You'd use the AXE formula where you'd look at the central atom of the compound and determine how many atoms are bonded to it and how many lone pairs it has.
- Sun Dec 08, 2019 7:53 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: pH formula?
- Replies: 69
- Views: 4130
Re: pH formula?
You could find pH using pH=-log[H+]. Or, if you have the pOH, you could subtract it from 14 to find the pH.
- Sun Dec 01, 2019 4:35 pm
- Forum: Naming
- Topic: Roman numerals
- Replies: 6
- Views: 505
Re: Roman numerals
You can determine the roman numeral by finding the charge of the transition metal. If the charge is not given, you can calculate the charges of each ligand and subtracting it from the overall charge.
- Sun Dec 01, 2019 4:29 pm
- Forum: Student Social/Study Group
- Topic: Final Topics
- Replies: 4
- Views: 281
Re: Final Topics
We didn't really focus on spectroscopy, so I don't think we'll see in on the final?? I'd focus more on what he went over in class.
- Sun Dec 01, 2019 4:26 pm
- Forum: Sigma & Pi Bonds
- Topic: Drawing Sigma and Pi bonds
- Replies: 7
- Views: 776
Re: Drawing Sigma and Pi bonds
You would label the sigma and pi bonds separately for the double bond. The same would apply for a triple bond.
And yes, when there are multiple single bonds, labeling every single bond with a sigma is correct.
And yes, when there are multiple single bonds, labeling every single bond with a sigma is correct.
- Sun Dec 01, 2019 3:54 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination Number
- Replies: 6
- Views: 411
Re: Coordination Number
You can determine the coordination number by counting the number of ligands that are bonded with the central atom. For Ba[FeBr4]2, you would focus on what is in the bracket. Iron, the transition metal, has 4 ligands bonded to it. Therefore, the coordination number for your example would be 4.
- Sun Dec 01, 2019 2:03 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate = more than one lone pair?
- Replies: 4
- Views: 271
Re: Polydentate = more than one lone pair?
Polydentate ligands have two or more lone pair donating sites.
- Sun Nov 24, 2019 1:36 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: dipole-dipole in a solid phase vs gas phase
- Replies: 15
- Views: 1207
Re: dipole-dipole in a solid phase vs gas phase
Dipole-dipole in a solid phase would be stronger. The bonds in a solid are tightly held and rigid unlike those of a gas. This would mean that the attraction between the molecules in the solid phase would be greater.
- Sun Nov 24, 2019 1:28 am
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: AXE formula
- Replies: 32
- Views: 12258
Re: AXE formula
Yes, it's definitely possible! You just have to be able to know which formula corresponds with which shape.
- Sun Nov 24, 2019 1:26 am
- Forum: General Science Questions
- Topic: Sig Figs
- Replies: 7
- Views: 461
Re: Sig Figs
Honestly I think it depends on your TA, but just to be safe you should use the right number of sig figs.
- Sun Nov 24, 2019 1:20 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent vs linear
- Replies: 56
- Views: 4312
Re: Bent vs linear
You could draw the Lewis structure and determine the VSEPR formula. A formula of AX2E or AX2E2 would indicate that the molecule is bent. AX2 or AX2E3 would be linear.
Re: Prefixes
EthanPham_4D wrote:Can anyone provide an example of the naming with these prefixes? I would like to see how it's used.
An example could be the compound ChloroBISethyleneDIaminecobalt(III)Sulfate. Because the ligand has the same prefix as the polydentate (di-), the second prefix, bis- is used.
- Thu Nov 14, 2019 11:54 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lewis Structures & VSEPR
- Replies: 9
- Views: 495
Re: Lewis Structures & VSEPR
I don't think it's necessary, but I think it can help you determine the VSEPR structure if there are lone pairs.
- Thu Nov 14, 2019 11:28 pm
- Forum: Hybridization
- Topic: Pi and Sigma Bonds
- Replies: 17
- Views: 1281
Re: Pi and Sigma Bonds
A single bond would have 1 sigma bond, a double bond would have a sigma bond and a pi bond, and a triple bond would have a sigma bond and 2 bonds.
- Thu Nov 14, 2019 10:51 pm
- Forum: Ionic & Covalent Bonds
- Topic: covalent bonds
- Replies: 7
- Views: 474
Re: covalent bonds
There are three types of covalent bonds: polar, nonpolar, and coordinate. Polar and nonpolar covalent bonds can be distinguished by differences in electronegativities and coordinate covalent bonds involve sharing electrons in order to order fill up shells.
- Thu Nov 14, 2019 11:41 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Formula
- Replies: 3
- Views: 196
Re: VSEPR Formula
The VSEPR formula is AXnEm, where A is the central atom, Xn represents the atoms attached to the central atom, and Em represents the lone electron pairs.
- Thu Nov 14, 2019 11:23 am
- Forum: Administrative Questions and Class Announcements
- Topic: TEST 2
- Replies: 8
- Views: 463
Re: TEST 2
I'm guessing everything we covered after the midterm?
- Sun Nov 10, 2019 4:41 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Equation?
- Replies: 12
- Views: 571
Re: Formal Charge Equation?
You could use Formal Charge= Valence Electrons + (Lone Pairs - Bonds/2), but an easier way to calculate the formal charge is to check the valence electron of the element and subtract the number of dots and lines it has.
- Sun Nov 10, 2019 4:36 pm
- Forum: Photoelectric Effect
- Topic: frequency and ejection of electrons
- Replies: 7
- Views: 810
Re: frequency and ejection of electrons
According to the photoelectric effect, frequency is directly proportional to the ejection of electrons. However, these electrons will only be ejected if the threshold energy is met.
- Sun Nov 10, 2019 4:30 pm
- Forum: Lewis Structures
- Topic: Exceptions like Xenon
- Replies: 3
- Views: 230
Re: Exceptions like Xenon
Elements that can go into the d-orbital can follow the same exception and have more than 8 electrons.
- Sun Nov 10, 2019 4:11 pm
- Forum: Administrative Questions and Class Announcements
- Topic: UA Workshops 11/11
- Replies: 2
- Views: 180
Re: UA Workshops 11/11
I don't think there are
- Sun Nov 10, 2019 4:06 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: how to draw lewis structure
- Replies: 9
- Views: 941
Re: how to draw lewis structure
Count the valence electrons, try to make each element form a complete octet, and then check your formal charges.
- Sat Nov 02, 2019 12:16 pm
- Forum: DeBroglie Equation
- Topic: Question about Converting Units
- Replies: 3
- Views: 134
Re: Question about Converting Units
the conversion from eV to J should be given on the test I think
- Sat Nov 02, 2019 12:16 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Energy change and Energy of photon
- Replies: 5
- Views: 361
Re: Energy change and Energy of photon
Going from a higher energy level to a lower, the change is negative, but photon energy is always positive, so if you set them equal to each other you would need a negative sign.
- Sat Nov 02, 2019 12:13 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: General Question about Orbital... Filling..?
- Replies: 5
- Views: 172
Re: General Question about Orbital... Filling..?
Yes I am pretty sure you have to write it in order of increasing number or you will lose points. It also helps when writing configurations for cations to tell which electrons to remove.
- Sat Nov 02, 2019 12:12 pm
- Forum: Trends in The Periodic Table
- Topic: Electronegativity trend exception
- Replies: 3
- Views: 2252
Re: Electronegativity trend exception
Lyndon was talking about an exception to the trend with ionization energy and electron affinity. Electronegativity does not have those same exceptions. O is more electronegative than N.
- Sat Nov 02, 2019 12:09 pm
- Forum: Photoelectric Effect
- Topic: Work Function
- Replies: 6
- Views: 396
Re: Work Function
It is the threshold energy, or the energy required to remove an electron from a metal surface. The threshold energy will vary based on the type of each metal. When the unit is J/mol, it is calculating the energy required to remove a mol of electrons.
- Sat Nov 02, 2019 12:05 pm
- Forum: Lewis Structures
- Topic: Valence Electrons from Periodic Table
- Replies: 10
- Views: 692
Re: Valence Electrons from Periodic Table
You can look at the group numbers on the periodic table, but this doesn’t apply to d-block elements. For groups 13-18, the valence electrons correspond to the number that is in the ones place. So oxygen, for instance, is in group 16 so it would have 6 valence electrons.
- Wed Oct 23, 2019 5:10 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 2A.5
- Replies: 4
- Views: 183
Re: 2A.5
I had problems with this at first too, but I think it has to do with the element being ionized. You're supposed to fill the d block first so that it's more stable(?), and you do this by taking the 2 electrons from the 4s orbital and moving them to the 3d orbital. This now makes the configuration for...
- Wed Oct 23, 2019 4:49 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: electron configurations
- Replies: 2
- Views: 148
Re: electron configurations
I think you meant [He] haha but anyways, I think one thing you could do is count up the number of electrons in the given configuration and compare the total to the element on the periodic table that has the total as its atomic number. If the elements match, then the configuration is in the grounded ...
- Wed Oct 23, 2019 4:36 pm
- Forum: Lewis Structures
- Topic: Finding Valence Electrons
- Replies: 8
- Views: 434
Re: Finding Valence Electrons
The number of valence electrons an element has corresponds with the group/ column it is under on the periodic table. For example, oxygen is in group 6 of the periodic table, therefore it has 6 valence electrons.
Hope this helps!
Hope this helps!
- Wed Oct 23, 2019 4:18 pm
- Forum: Trends in The Periodic Table
- Topic: Trend in periodic table
- Replies: 6
- Views: 245
Re: Trend in periodic table
Going down the table, elements in the same column, or group, have the same number valence electrons and share similar characteristics.
- Wed Oct 23, 2019 12:49 pm
- Forum: Ionic & Covalent Bonds
- Topic: Difference Between Ionic and Covalent
- Replies: 8
- Views: 1059
Re: Difference Between Ionic and Covalent
An ionic bond is a bond that is shared between a metal and a non-metal. These metals can also be referred to as ions (atom/molecule that loses or gains an electron). Ions that gain an electron (have a negative charge) are known as anions and those that lose electrons (positively charged) are cations...
- Sun Oct 20, 2019 7:22 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Best Way To Study?
- Replies: 56
- Views: 3568
Re: Best Way To Study?
So far, I've been reviewing the modules on Lavelle's website and worked on all of the homework problems listed on the class syllabus.
- Sun Oct 20, 2019 12:07 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Exceptions for Electron Configuration
- Replies: 6
- Views: 241
Re: Exceptions for Electron Configuration
I believe they were copper (Cu) and chromium (Cr). The configuration for copper would be [Ar]3d10 4s1 and chromium would be [Ar]3d5 4s1.
- Sun Oct 20, 2019 12:05 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron configurations for Ni and Sc
- Replies: 1
- Views: 126
Re: Electron configurations for Ni and Sc
On the periodic table, 3d starts from Scandium (Sc) and ends at Zinc (Zn). You can think of it as each element having a humber that corresponds with their position or order in that row. So Sc would be 1, Ti would be 2,..etc. Because Sc is first in the 3d row its configuration would be [Ar]3d1 4s2 an...
- Sun Oct 20, 2019 11:56 am
- Forum: Properties of Light
- Topic: 1A.9 Energy of Photon
- Replies: 12
- Views: 508
Re: 1A.9 Energy of Photon
You can try to solve for the frequency and once you get that, use the formula E= (Plank's constant)*(frequency), or E=hv, in order to get the energy of the photon. If you are given the wavelength and not the frequency, you could use wavelength to find the frequency by using formula v (frequency) = s...
- Tue Oct 15, 2019 10:02 pm
- Forum: Properties of Light
- Topic: Homework 1A.15
- Replies: 1
- Views: 137
Homework 1A.15
"In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line."
I'm not sure how to approach this problem. Can someone help?
I'm not sure how to approach this problem. Can someone help?
- Sun Oct 13, 2019 1:58 pm
- Forum: General Science Questions
- Topic: Units question for 1B.5
- Replies: 2
- Views: 146
Re: Units question for 1B.5
keV is the notation for kiloelectron volt. If you want to convert this to joules you could convert keV into units of eV by multiplying the amount given in keV by 1000 eV/1keV to cancel out the keV's. Now that your units are in eV you could convert eV into joules by using the conversion factor 1 eV =...
- Sun Oct 13, 2019 1:35 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Circular Standing Waves and "in phase"
- Replies: 2
- Views: 132
Re: Circular Standing Waves and "in phase"
The textbook uses "in phase" to describe the relationship between two waves. When both waves have the same frequencies and coincide with each in terms of their peaks and troughs, they're said to be in phase. "Out of phase", on the other hand, would mean that the troughs of one of...
- Sun Oct 13, 2019 4:58 am
- Forum: Properties of Electrons
- Topic: Electron Quantum Energies
- Replies: 3
- Views: 200
Re: Electron Quantum Energies
The relationship between a particle's wavelength and its energy is what establishes the quantization of energy levels. Imagine a particle that's in a box. Unlike classical mechanics which states that the energy of an object could be at any value, the particle could bounce off on any direction of the...
- Sat Oct 12, 2019 11:12 pm
- Forum: Balancing Chemical Reactions
- Topic: F.3
- Replies: 5
- Views: 382
Re: F.3
I'm not sure if we are expected to derive the formulas on our own, but hopefully this helps: For part a, it helps to know that acids contain hydrogen and usually begin with an H. So, that gives you the first element of nitric acid. For the rest of the formula, I had to work backward. When you are us...
- Fri Oct 11, 2019 4:30 pm
- Forum: Significant Figures
- Topic: Sig Figs in Answer
- Replies: 8
- Views: 458
Re: Sig Figs in Answer
Because it's not specified, I think using 3 or 4 sig figs would be fine. Having 4 sig figs would make your answer a bit more accurate, but I think using 3 would also be completely fine.
- Sat Oct 05, 2019 10:28 pm
- Forum: SI Units, Unit Conversions
- Topic: Negative and Non-Negative powers
- Replies: 2
- Views: 198
Re: Negative and Non-Negative powers
You have the right idea! Positive powers indicate that you move the decimal point to the right, while negative powers indicate that you move the decimal point to the left. So keeping that in mind, giga- would be in factors of 1,000,000,000 while nano- would be .000000001.