Search found 71 matches
- Tue Mar 12, 2019 4:00 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3917130
Re: Post All Chemistry Jokes Here
I was gonna tell a chemistry joke, but then I thought "Na... no one would get it."
- Tue Mar 12, 2019 3:56 pm
- Forum: General Rate Laws
- Topic: second and zeroth order half life "not used"
- Replies: 2
- Views: 305
Re: second and zeroth order half life "not used"
For a first order reaction, the half life is the same value regardless of where you are in the reaction. However, in second and zeroth order reactions, the half life value changes depending on the concentration, so it's more difficult to calculate and therefore not as useful.
- Tue Mar 12, 2019 3:49 pm
- Forum: Student Social/Study Group
- Topic: Studying for the Final
- Replies: 25
- Views: 2876
Re: Studying for the Final
A lot of the TA's post a lot of review problems and their weekly worksheets that they hand out in discussion as well!
- Mon Mar 11, 2019 12:00 am
- Forum: Second Order Reactions
- Topic: Rounding Reaction Orders
- Replies: 4
- Views: 482
Re: Rounding Reaction Orders
Would be acceptable to not round the order and only round the value of the answer, which may be the rate constant, for example? I'd suggest that you round the order rather than the value of the answer, since in the textbook and in lectures, we've only seen reaction orders as whole numbers rather th...
- Thu Mar 07, 2019 5:17 pm
- Forum: Second Order Reactions
- Topic: Rounding Reaction Orders
- Replies: 4
- Views: 482
Re: Rounding Reaction Orders
We round these values because of the possible experimental errors that could occur when we don't round. Plus it just makes calculations easier! Hope this helps!
- Thu Mar 07, 2019 5:07 pm
- Forum: General Rate Laws
- Topic: a = reaction order
- Replies: 1
- Views: 206
Re: a = reaction order
No there is no correlation between the order of a reaction and the chemical coefficients.
- Thu Mar 07, 2019 4:49 pm
- Forum: General Rate Laws
- Topic: units for k
- Replies: 1
- Views: 232
Re: units for k
It might just be mixed up between the conversion between mmol and mol. But mmol and sec should be in the denominator.
- Thu Mar 07, 2019 4:48 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Homework for Week 9
- Replies: 3
- Views: 474
Re: Homework for Week 9
I just did some Nernst Equation problems and the beginning of the chemical kinetics.
- Thu Mar 07, 2019 4:43 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: k constant
- Replies: 2
- Views: 598
Re: k constant
Reactions rates are always positive and since k is a proportionality constant that relates some given concentration (which are always positive) with the rate (also always positive), it's not possible for k to be negative.
- Thu Mar 07, 2019 4:38 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Nernst Equation
- Replies: 1
- Views: 296
Re: Nernst Equation
They will both produce the same value. As long as you have the conversion accounted for in the RT/nF term already.
- Wed Feb 20, 2019 6:24 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electromotive force
- Replies: 2
- Views: 303
Re: Electromotive force
In the textbook, it'll be sometimes referred to as just E, so don't get confused with emf and E.
- Wed Feb 20, 2019 6:22 pm
- Forum: Van't Hoff Equation
- Topic: ΔSº and ΔHº question
- Replies: 5
- Views: 694
Re: ΔSº and ΔHº question
Yes only free energy can be greatly influenced by a change in temperature.
- Wed Feb 20, 2019 4:57 pm
- Forum: Balancing Redox Reactions
- Topic: Adding Salt Bridge/Porous Disk to Reaction Beakers
- Replies: 2
- Views: 299
Re: Adding Salt Bridge/Porous Disk to Reaction Beakers
As electrons are transferred from the anode to the cathode, there is a salt that builds up which would create a charge gradient. In order to maintain a neutral solution, there needs to be a salt bridge that balances the charges.
- Wed Feb 20, 2019 4:47 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Potential Difference Between Electrodes
- Replies: 1
- Views: 222
Re: Potential Difference Between Electrodes
Because you can think of it like the maximum difference in volume between two connected beakers of water. The beaker that has all the water compared to the beaker with no water will show how there is a larger difference. Even at a little flow, the difference in volume will be a large value. This can...
- Tue Feb 19, 2019 4:12 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Cp vs Cv
- Replies: 7
- Views: 1102
Re: Cp vs Cv
Going off of what Sophia said, unless there is something in the problem that explicitly states that pressure is constant, you will always use the Cv constant because we can't assume that pressure is constant when nothing within the problem mentions pressure.
- Tue Feb 19, 2019 3:40 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterms
- Replies: 4
- Views: 568
Re: Midterms
I don't think that there will be curve for the midterm. The only curve that Dr. Lavelle uses is one based on the glass grade by the end of the quarter.
- Sun Feb 10, 2019 2:20 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Delta U
- Replies: 8
- Views: 894
Re: Delta U
Well delta U can still have a nonzero value at isothermal, reversible processes depending on what w is. So when we know that the system undergoes an isothermal, reversible process, we know that heat (q) = 0 and therefore the only thing left for delta U to equal is w. So at isothermal, reversible pro...
- Thu Feb 07, 2019 5:44 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Study Guides
- Replies: 15
- Views: 1292
Re: Study Guides
I wouldn't be sure about very sure about that. He did state earlier this quarter that making his own problems for midterm reviews is harder for 14B because making the numbers work out is more complicated compared to 14A. So for now, I'd just recommend going over the homework problems and looking at ...
- Thu Feb 07, 2019 5:41 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: 7th Edition 4A.3
- Replies: 2
- Views: 323
Re: 7th Edition 4A.3
No it didn't.
- Tue Feb 05, 2019 4:20 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: 7th Edition 4A.3
- Replies: 2
- Views: 323
7th Edition 4A.3
For this problem, my answer for how much work was done was correct according to the solutions manual. However, part c asks for the change in internal energy of the system. My logic was that because there was no heat involved in the scenario, deltaU would just be equal to the work done on the system,...
- Tue Feb 05, 2019 3:43 pm
- Forum: Calculating Work of Expansion
- Topic: Gas Constant
- Replies: 3
- Views: 462
Re: Gas Constant
I believe the one that is most often used is the 8.314 J.K^-1.mol^-1 one. However, each constant will be on the constants and equations sheet for the midterms/tests, so just pay attention to your units and which ones you need to cancel out, and you'll know which gas constant to use.
- Sun Feb 03, 2019 2:51 am
- Forum: Phase Changes & Related Calculations
- Topic: PΔV for solids and liquids
- Replies: 5
- Views: 524
Re: PΔV for solids and liquids
You could also think of solids and liquids as not having much volume change at all, which in result allows us to make the estimation saying that delta V for a solid or liquid is essentially zero.
- Sun Feb 03, 2019 2:49 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Calorimeter
- Replies: 6
- Views: 578
Re: Calorimeter
I don't think we need to know how to set up a calorimeter experiment specifically, but you should be able to recall that bomb calorimeters/calorimetry in general is an example of an isolation system.
- Sun Feb 03, 2019 2:47 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: kJ v. kJ/mol
- Replies: 3
- Views: 566
Re: kJ v. kJ/mol
Yeah I believe that Christina is correct. The overall enthalpy of a chemical reaction should be measured in kJ while other enthalpies for specific chemical species should be measured in kJ/mol unless specified.
- Sat Jan 26, 2019 7:23 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies
- Replies: 3
- Views: 347
Re: Bond Enthalpies
This method is known to be the most inaccurate one of the three however, so I don't think we'll be using this method much, other than in homework problems.
- Sat Jan 26, 2019 7:14 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: method 1
- Replies: 3
- Views: 328
Re: method 1
Those chemical species that are a product of one reaction but also the reactant of another are considered intermediates, so you don't have to worry about them when using Method 1.
- Sat Jan 26, 2019 7:02 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: In the last lecture
- Replies: 3
- Views: 393
Re: In the last lecture
Also remember that the second method is the most inaccurate method of calculating the overall enthalpy of a reaction however. The reason being is that the values that we have for the bond enthalpies are only averages taken over a different number of molecules. The actual bond enthalpy for certain bo...
- Tue Jan 15, 2019 1:11 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: When is X assumed to be negligible?
- Replies: 1
- Views: 234
Re: When is X assumed to be negligible?
Dr. Lavelle said that if K is around 10^-3, then it's a safe range to say that the change x is negligible, but I'd say that 10^-4 is a safer value.
- Tue Jan 15, 2019 12:59 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kw
- Replies: 2
- Views: 240
Re: Kw
Yeah I believe that for now, it's safe to assume that the temperature will be 25 degrees C and that pKw is 14.
- Tue Jan 15, 2019 12:56 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Simplifying Cubic Equations
- Replies: 2
- Views: 374
Re: Simplifying Cubic Equations
Simplifying Cubic Equations is essentially the same process of quadratic equations because once you simplify one of the equilibrium terms, it'll just give you a quadratic equation or simple equation where you solve for x. This will be able to happen if the K constant they give you is small enough to...
- Sat Jan 12, 2019 1:28 am
- Forum: Ideal Gases
- Topic: Q and K [ENDORSED]
- Replies: 35
- Views: 3242
Re: Q and K [ENDORSED]
Tony Ong 3K wrote:nope no difference! Hope that helped because I have to sleep now!
Goodnight!
- Tue Jan 08, 2019 8:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc vs. Kp
- Replies: 7
- Views: 688
Re: Kc vs. Kp
Like others said, Kp is specifically referring to the equilibrium constant when all relative molecules/atoms are in a gaseous phase, therefore you use partial pressures. Kc refers to the equilibrium constant with regards to the concentrations of reactants and products, so you would use molar concent...
- Tue Jan 08, 2019 5:50 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs. Q
- Replies: 2
- Views: 180
Re: K vs. Q
K is the equilibrium constant that reveals the ratio of products to reactants at the time in which the actual reaction is at equilibrium. Q, however, is the ratio of products to reactants at any other time during the reaction whether or not the reaction has reach equilibrium.
- Tue Jan 08, 2019 5:48 pm
- Forum: Ideal Gases
- Topic: Equilibrium Constants
- Replies: 4
- Views: 509
Re: Equilibrium Constants
If you double the moles of a certain molecule/atom in a chemical reaction, you'll have to take that coefficient and use it as the exponent for the concentration of that respective molecule/atom in the equilibrium constant.
- Thu Dec 06, 2018 11:59 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Distorted electrons
- Replies: 2
- Views: 463
Re: Distorted electrons
It's helpful to understand the trend of polarizable atoms. The larger the atom is or the more electrons the atom has, the more polarizable it is. This is because there will be more electron clouds that are not as strongly held by its nucleus' protons.
- Thu Dec 06, 2018 11:49 pm
- Forum: Naming
- Topic: Adding "o" to Anion
- Replies: 2
- Views: 270
Re: Adding "o" to Anion
Chloro and chlorido are interchangeable. I just go with chloro because it's shorter and like Sophia said, Dr. Lavelle used that form as well.
- Thu Dec 06, 2018 11:45 pm
- Forum: Naming
- Topic: 6th edition: 17.31d
- Replies: 1
- Views: 222
Re: 6th edition: 17.31d
I'm sure that in the end it doesn't matter what order you write the ligands in, as long as they come after the transition metal within the square brackets. If you want to be safe, I'd suggest just writing the ligands in the order of which you the compound name lists them. Other than that your answer...
- Sun Dec 02, 2018 12:55 am
- Forum: Naming
- Topic: endings in naming
- Replies: 3
- Views: 196
Re: endings in naming
There are also other cases where the ending of certain things change. For example, in a complex the metal should have an "-ate" ending if the overall charge of the complex is negative (ie. cobalt --> colbaltate). Have a good night!
- Wed Nov 28, 2018 7:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Tetrahedral
- Replies: 2
- Views: 279
Re: Tetrahedral
There can be slight modifications such as one of the atoms making up the tetrahedral that isn't the same as the other atoms being large enough to push the others closer together, which would make some of the bond angles slightly less than 109.5 degrees and the bond angle with the larger atom would b...
- Wed Nov 28, 2018 7:49 pm
- Forum: Bronsted Acids & Bases
- Topic: Bronsted vs Lewis
- Replies: 2
- Views: 262
Re: Bronsted vs Lewis
Both are interchangeable, just make sure you know that the lewis definition deals with lone pair donor and acceptor while the bronsted definition views it in terms of proton donor and acceptor.
- Fri Nov 23, 2018 11:59 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Strengths of Repulsions
- Replies: 1
- Views: 233
Re: Strengths of Repulsions
The significance of this rule is that it can completely alter the shape of the molecule after drawing the VSEPR model. When we say that the lone pair-lone pair repulsion is the strongest of them all, it means that when we draw a VSEPR model, we try to separate those two as far away as possible, even...
- Fri Nov 23, 2018 6:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Position of atoms in Trigonal Planar
- Replies: 4
- Views: 408
Re: Position of atoms in Trigonal Planar
LeannaPhan14ALec1Dis1F wrote:This applies to the angles?
Yeah this should also apply to the angles as well. Any molecule that is trigonal planar will have 120 degree angles between each pair of bonded atoms.
- Fri Nov 23, 2018 5:45 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Position of atoms in Trigonal Planar
- Replies: 4
- Views: 408
Re: Position of atoms in Trigonal Planar
It shouldn't matter as long as the overall structure is an equilateral triangle if you were to draw straight lines connecting the atoms surrounding the central atom.
- Fri Nov 23, 2018 5:42 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs on the Central Atom
- Replies: 5
- Views: 541
Re: Lone Pairs on the Central Atom
It's also to keep in mind how lone pair repulsions are the strongest of them all, overpowering a lone pair-bonded pair and bond-bond repulsion. So lone pairs have a significant impact on the 3-D shape of the molecule.
- Tue Nov 13, 2018 6:32 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm
- Replies: 4
- Views: 597
Re: Midterm
Professor Lavelle told us that we would be getting the midterm tomorrow during class, and I think the comments will be up to your TA. You could always ask your TA during discussion too.
- Tue Nov 13, 2018 6:29 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 8
- Views: 1430
Re: Bond Angles
I believe that bond angles in VSEPR models are just something that you have to memorize with certain shapes. There's no way to calculate bond angles as of right now.
- Tue Nov 13, 2018 5:51 pm
- Forum: Electronegativity
- Topic: Polarity
- Replies: 3
- Views: 307
Re: Polarity
You might want to draw out the polarity ends when it comes to drawing multiple molecules that have an effect on each other (ie induced dipole-dipole). It'll just help with understanding what makes a molecule polar and the correlation between electrons and polarity.
- Fri Nov 09, 2018 10:57 am
- Forum: Octet Exceptions
- Topic: octet exceptions
- Replies: 4
- Views: 506
Re: octet exceptions
The first four elements (H, He, Li, Be) can have an incomplete octet since their electrons only pertain to the s-orbital which requires two electrons to be stable. Group 13 (B, Al, etc.) can also have an incomplete octet because that is just the exception that we need to know about. Any element in P...
- Fri Nov 09, 2018 10:54 am
- Forum: Resonance Structures
- Topic: Dominant resonance structure
- Replies: 4
- Views: 1777
Re: Dominant resonance structure
In some cases, multiple resonance structures can have a formal charge of 0, and if that structure has a central atom, a good way of determining which one is the most stable structure is to find the one where the central atom has a formal charge of 0.
- Fri Nov 09, 2018 10:49 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: ionic vs. covalent character
- Replies: 3
- Views: 409
Re: ionic vs. covalent character
I agree with Gillian. It's also important to understand that molecules that we consider one or the other will also display characteristics of the other, just to different extents.
- Thu Nov 01, 2018 4:35 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Questions on Midterm
- Replies: 4
- Views: 458
Re: Questions on Midterm
Lyndon Bui (one of our UA's) posted a practice packet that has questions derived from the previous exams as well, so if you just search "Garlic Bread" on the search bar you'll find it. This might give you a good measure on the trickier parts of previous exams. https://lavelle.chem.ucla.edu...
- Tue Oct 30, 2018 9:17 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2A.15
- Replies: 2
- Views: 315
Re: 2A.15
You can check this by analyzing the ionization energy of each of them. Each element wants to become stable by either losing or gaining electrons so that their outermost shell follows the octet rule. For example, the element Sulfur has relatively high ionization energy and has 6 valence electrons. Th...
- Tue Oct 30, 2018 9:13 pm
- Forum: Octet Exceptions
- Topic: octet rule exceptions?
- Replies: 5
- Views: 797
Re: octet rule exceptions?
Yes elements within the 3rd period/row can have more electrons than the octet rule allows. Also, the first four elements (Hydrogen, Helium, Lithium and Beryllium) and elements in column 14 can have incomplete octets (less that 8 electrons).
- Mon Oct 29, 2018 11:28 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 1E.13
- Replies: 3
- Views: 476
Re: 1E.13
Yeah this would be another example of that exception in electron configurations. The transition metals from Copper and and Chromium take one electron from the 4s orbital to either have a half filled 3d orbital (in the case of Chromium) or a fully filled 3d orbital (in the case of silver).
- Mon Oct 22, 2018 7:52 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 4s vs. 3d
- Replies: 1
- Views: 214
Re: 4s vs. 3d
We aren't sure based on what we learned in lecture today. All Dr. Lavelle said was that we wouldn't be able to tell just by looking at the periodic table, rather we know that 3d has a lower energy than 4s because it was measured and given to us as a scientific fact.
- Mon Oct 22, 2018 5:10 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Test 2 and Homework Problems
- Replies: 6
- Views: 682
Re: Test 2 and Homework Problems
Yeah that looks about right, since 2.45 and forward is all the stuff we learned in lecture today and will learn in the upcoming lectures.
- Mon Oct 22, 2018 4:56 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Test 2
- Replies: 2
- Views: 250
Re: Test 2
We don't need to know electron configurations for this upcoming test. Dr. Lavelle said Test 2 consists of all the first half of quantum up to the quantum number material we learned about on last Friday's lecture.
- Tue Oct 16, 2018 1:52 am
- Forum: Administrative Questions and Class Announcements
- Topic: Writing in Pen
- Replies: 13
- Views: 1052
Re: Writing in Pen
My TA personally requested that we did the first test in pen but I guess it's up to the TA. However, on the syllabus, Dr. Lavelle states that "All tests and exams are closed book and must be written in pen." So get used to it by using pen on homework if you feel like it.
- Tue Oct 16, 2018 1:46 am
- Forum: Administrative Questions and Class Announcements
- Topic: Chem Community Grading
- Replies: 2
- Views: 231
Chem Community Grading
I'm not sure if a question like this has been asked before but do posts on Sunday count as posts for Week 3 or Week 2? I responded to a couple posts on Sunday night (October 14) and was wondering what academic week it would apply for, since at the time the CCLE front page still said Week 2 at the ti...
- Tue Oct 16, 2018 1:41 am
- Forum: *Black Body Radiation
- Topic: Black Bodies and Temperature
- Replies: 2
- Views: 638
Re: Black Bodies and Temperature
As the temperature of the black body increases, the frequency of the light that causes that temperature increases as well. In other words, frequency is proportional to energy of a certain radiation. However, wavelength and frequency have an inverse proportional relationship, so as the frequency of t...
- Sun Oct 14, 2018 11:43 pm
- Forum: Properties of Light
- Topic: Experiments and Equations
- Replies: 3
- Views: 174
Re: Experiments and Equations
Based off of the way that our first quiz went, I don't think you need to know too much about the history of those experiments. Many of the problems assigned for homework are more mathematical and application-based so just study the formulas and steps needed for certain types of problems and you'll b...
- Sun Oct 14, 2018 11:40 pm
- Forum: Student Social/Study Group
- Topic: Studying techniques
- Replies: 12
- Views: 853
Re: Studying techniques
Besides doing all the homework problems, you've probably also heard about going to your TA hours or Dr. Lavelle's office hours for help. I would recommend going to the UA Peer Learning Sessions that have the different levels like step by step reviewing/extra practice or the more fast paced sessions ...
- Sun Oct 14, 2018 11:30 pm
- Forum: Student Social/Study Group
- Topic: Note Taking
- Replies: 145
- Views: 19452
Re: Note Taking
This might sound a little unnecessary but when it comes to the detailed notes and jotting down key concepts, you could type them so that when you go back to study them, you'll have clean, neat words that fully explain the concept without having to use so many abbreviations and shortened versions of ...
- Tue Oct 09, 2018 7:23 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Rounding on Exams
- Replies: 1
- Views: 224
Re: Rounding on Exams
For the most part, you should get partial credit because the TA grading your test should be able to see that you were on the right track and interpreted the question correctly. If your main problem is being off by a hundredth from the correct answer, it could be your use of sig figs and rounding too...
- Tue Oct 09, 2018 5:42 pm
- Forum: SI Units, Unit Conversions
- Topic: Quiz 1- Addition to what we should know?
- Replies: 5
- Views: 620
Re: Quiz 1- Addition to what we should know?
I made sure to ask Dr. Lavelle this same question! For this quiz, we don't have to know the formulas of anions or cations like the ones you exemplified. However, expect to have to know some in the future for later quizzes!
- Tue Oct 09, 2018 5:39 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Fundamentals E.15
- Replies: 3
- Views: 315
Re: Fundamentals E.15
Can there ever be an unidentified solid/gas and you would do the same thing Or willl we only ever come across unidentified metals? Yeah there are possibilities that this same type of question could appear but with gases instead of metals. It's just that in terms of the periodic table, there are man...
- Thu Oct 04, 2018 4:26 pm
- Forum: Balancing Chemical Reactions
- Topic: H.11 part 2 balancing tricks?
- Replies: 2
- Views: 261
Re: H.11 part 2 balancing tricks?
You could always leave the element that is by itself for last. In this case, the Fe is pure iron so just focus on balancing the carbon and oxygen first, then look at the Fe which is easy since there is only one mole of it.
- Sun Sep 30, 2018 3:45 pm
- Forum: SI Units, Unit Conversions
- Topic: How does grading for discussion posts work?
- Replies: 80
- Views: 9332
Re: How does grading for discussion posts work?
Does anyone know when our first homework assignment is due? Is it due on the Friday of week 1 during lecture or during our discussion in week 1? Also, I remember Professor Lavelle saying that we can "choose" our homework. Does that mean we can go through our textbook and choose the questi...
- Sat Sep 29, 2018 11:04 pm
- Forum: Limiting Reactant Calculations
- Topic: Calculating Required Moles
- Replies: 2
- Views: 249
Re: Calculating Required Moles
Since you know the moles of each reactant in the equation, along with the molar ratio between the two reactants (being 4 moles of NH3 for every 5 moles of O2) you would just have to multiply it by 4/5. If you want to know how many moles of NH3 you need for 0.266 moles of O2, you would multiply the 0...
- Sat Sep 29, 2018 11:03 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Do we have to write out the question for homework?
- Replies: 4
- Views: 520
Re: Do we have to write out the question for homework?
I'm pretty sure you don't have to write out the question. Just make sure to write the chapter, question number, and the edition of the textbook that that certain question is from, since Dr. Lavelle allows us to use the 6th and 7th edition for homework!
- Sat Sep 29, 2018 5:42 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Question E16 - Transition Metal Charge
- Replies: 4
- Views: 421
Re: Question E16 - Transition Metal Charge
Yes the charge of Ag would be +1 in this case. Transition metals are stated to have an oxidation state of 0 (having no charge) so when combined with another element like Cl which usually has a -1 charge in chemistry problems, you assume that the transition metal takes on a charge that would stabiliz...