Search found 100 matches
- Sat Mar 13, 2021 4:39 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Inert electrode
- Replies: 3
- Views: 253
Re: Inert electrode
Hi! I believe Pt(s) is used more but I don't think you'll get docked any points for having one over the other. Since the final is multiple choice, you can just change the inert electrode depending on what the choices give you.
- Sat Mar 13, 2021 4:37 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Anode and Cathode
- Replies: 25
- Views: 1208
Re: Anode and Cathode
Hi! The anode is always the site of oxidation and the cathode is always the site of reduction.
- Sat Mar 13, 2021 4:36 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: H+ and Pt in Cell Diagrams
- Replies: 3
- Views: 286
Re: H+ and Pt in Cell Diagrams
Hi! Anything other than H20 (l) has to be included in the cell diagrams, so H+ and OH+ always need to be added if they're part of the half-reaction. Pt is added when there's no solid conductor, but the one exception is Hg(l), which is a liquid conductor.
- Sat Mar 13, 2021 4:34 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagrams
- Replies: 2
- Views: 199
Re: Cell Diagrams
Hi! 1. You do not have to include the stoichiometric coefficients in the cell diagram. 2. We use commas instead of the line (|) when the two substances/molecules are in the same phase. The line is used when they're in different phases. 3. Order doesn't matter as long as the anode is on the left and ...
- Sat Mar 13, 2021 4:31 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: About k
- Replies: 26
- Views: 2735
Re: About k
Hi! Lowercase k represents the rate constant, whereas upper case K represents the equilibrium constant
- Mon Mar 08, 2021 10:15 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K
- Replies: 33
- Views: 1242
Re: K
Hi! K is the equilibrium constant and is the broader/umbrella term for the equilibrium constant. Kc is the equilibrium constant that is calculated with molar concentrations.
- Mon Mar 08, 2021 10:13 am
- Forum: Calculating Work of Expansion
- Topic: R constant of an Ideal Gas
- Replies: 16
- Views: 721
Re: R constant of an Ideal Gas
Hi! For me what's worked best has been just looking at what units you need for the end result and adjusting accordingly.
- Mon Mar 08, 2021 10:12 am
- Forum: Calculating Work of Expansion
- Topic: Negative Work
- Replies: 30
- Views: 1164
Re: Negative Work
Hi! If the system is doing work on the surroundings, then the work would be a negative value.
- Sun Mar 07, 2021 9:43 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Is thermal mugs an example of an isolated system?
- Replies: 38
- Views: 1895
Re: Is thermal mugs an example of an isolated system?
Hi! I believe if the thermal mug is completely sealed then yes it would be considered an example of an isolated system.
- Sun Mar 07, 2021 9:41 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Meaning of K
- Replies: 55
- Views: 3673
Re: Meaning of K
Hi! Usually, K stands for equilibrium constant OR the temperature unit Kelvin.
- Sun Feb 28, 2021 11:00 am
- Forum: Calculating Work of Expansion
- Topic: Reversible vs Irreversible
- Replies: 9
- Views: 630
Re: Reversible vs Irreversible
Reversible expansions utilize the equation w=-nRTln(V2/V1), have a delta S total equal to zero, and are usually have a greater work value than the irreversible counterpart. Irreversible expansions utilize the w=-P(delta V), involve less work done, and have a delta S surroundings equal to 0. Hope thi...
- Sun Feb 28, 2021 11:00 am
- Forum: Calculating Work of Expansion
- Topic: Irreversible Vs. Reversible Expansion
- Replies: 4
- Views: 361
Re: Irreversible Vs. Reversible Expansion
Hi! Reversible expansions utilize the equation w=-nRTln(V2/V1), have a delta S total equal to zero, and are usually have a greater work value than the irreversible counterpart. Irreversible expansions utilize the w=-P(delta V), involve less work done, and have a delta S surroundings equal to 0.
- Sun Feb 28, 2021 10:57 am
- Forum: Calculating Work of Expansion
- Topic: Finding Reversibility
- Replies: 8
- Views: 461
Re: Finding Reversibility
Hi! Some signs that a reaction is reversible are that the delta S total equals 0, and if the problem includes values for the number of moles, temperature, and the two volumes.
- Sun Feb 28, 2021 10:45 am
- Forum: Ideal Gases
- Topic: STP
- Replies: 12
- Views: 1472
Re: STP
Hi! STP is at 273K, whereas room temperature (what you're thinking about) is 298K.
- Sun Feb 28, 2021 10:33 am
- Forum: Ideal Gases
- Topic: K and Q
- Replies: 57
- Views: 3061
Re: K and Q
Hi! K and Q are only equal to each other when the reaction is at equilibrium.
- Sun Feb 21, 2021 2:45 pm
- Forum: Calculating Work of Expansion
- Topic: Work Formula
- Replies: 15
- Views: 745
Re: Work Formula
Hi! You should only use the number of moles of gas in this calculation.
- Sun Feb 21, 2021 2:44 pm
- Forum: Calculating Work of Expansion
- Topic: Value of Q
- Replies: 20
- Views: 899
Re: Value of Q
Hi! The value of Q is the reaction quotient, which can be solved the same as you calculate K (the equilibrium constant).
- Sun Feb 21, 2021 2:43 pm
- Forum: Calculating Work of Expansion
- Topic: unit of w
- Replies: 17
- Views: 1128
Re: unit of w
Hi! You can convert your answer from -PdeltaV (which should be in L*atm) into joules by multiplying the answer by 101.325 J (101.325 = 1 L*atm).
- Sun Feb 21, 2021 2:41 pm
- Forum: Calculating Work of Expansion
- Topic: Spontaneous
- Replies: 26
- Views: 1440
Re: Spontaneous
Hi! You can tell if a system is spontaneous if the delta Gibbs free energy is negative. Also, an exothermic reaction is always spontaneous.
- Sun Feb 21, 2021 2:39 pm
- Forum: Calculating Work of Expansion
- Topic: Work sign
- Replies: 46
- Views: 1899
Re: Work sign
Hi! The work done by a system is negative, whereas the work done on a system is positive.
- Fri Feb 12, 2021 12:03 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Would an aq agent be included in K?
- Replies: 27
- Views: 960
Re: Would an aq agent be included in K?
Hi! Yes, the only two types of molecules that can be included in the calculation of K are aqueous and gaseous solutions.
- Fri Feb 12, 2021 12:02 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Making X negligible
- Replies: 34
- Views: 1301
Re: Making X negligible
Hi! X is neglible when the initial concentration for the reactant is 1000x larger than the Kc value.
- Fri Feb 12, 2021 12:00 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Factors that affect the equilibrium constant
- Replies: 31
- Views: 3973
Re: Factors that affect the equilibrium constant
Hi! I believe the only factor that affects the equilibrium constant is temperature.
- Fri Feb 12, 2021 11:57 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Telling Apart Weak Bases vs Weak Acids by their Formula
- Replies: 11
- Views: 783
Re: Telling Apart Weak Bases vs Weak Acids by their Formula
Hi! For me, I find that using flash cards to memorize the strong acids and bases is the best way to easily identify strong/weak acids and bases. Since there are a lot less strong acids and bases than their weak counterparts, I would just suggest knowing the strong acids and bases. Strong Acids: HCl,...
- Fri Feb 12, 2021 11:48 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc vs K
- Replies: 9
- Views: 473
Re: Kc vs K
Hi! K refers to the equilibrium constant and is the broader term for it, whereas Kc is the equilibrium constant which is calculated with molar concentrations.
- Sun Feb 07, 2021 12:13 pm
- Forum: Ideal Gases
- Topic: Kc vs. Kp
- Replies: 71
- Views: 2289
Re: Kc vs. Kp
Hi! Yes, we solve both the same way.
- Sun Feb 07, 2021 12:12 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Definition of an Inert Gas
- Replies: 15
- Views: 885
Re: Definition of an Inert Gas
Hi! Inert gases are gases that do not react / affect the chemical equilibrium. Examples of inert gases are the noble gases (Group 18)
- Sun Feb 07, 2021 12:10 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Strong vs Weak acid/Bases
- Replies: 10
- Views: 494
Re: Strong vs Weak acid/Bases
Hi! The reason we use the ICE tables for weak acids and bases and do not just treat them like strong acids and base pairings is because the weak acids and bases do not completely dissociate so we have to use the ICE tables.
- Sun Feb 07, 2021 12:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: pka vs ka
- Replies: 28
- Views: 1254
Re: pka vs ka
Hi! I believe the reasoning behind this is the logarithm function for pka (logab = log a + log b).
- Sun Feb 07, 2021 12:07 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Strong acids/bases
- Replies: 10
- Views: 534
Re: Strong acids/bases
Hi! Honestly, for me, I use flash cards to memorize the strong acids and bases. Since there are a lot less strong acids and bases than their weak counterparts, I would just suggest knowing the strong acids and bases. Strong Acids: HCl, HBr, HI, HClO3, HClO4, HNO3, H2SO4 Strong Bases: Group 1 hydroxi...
- Sat Jan 30, 2021 9:21 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Changes in Pressure
- Replies: 10
- Views: 377
Re: Changes in Pressure
Hi! Only the number of moles of GASES are used to determine whether the reaction moves left or right after a change in pressure/volume. Also, it's important to note that changes in pressure due to the addition of an inert gas does not change the equilibrium at all.
- Sat Jan 30, 2021 9:18 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy solving methods
- Replies: 7
- Views: 309
Re: Enthalpy solving methods
Hi! There are three methods and it's usually up to you on which one to use based on what the question supplies you with. 1. Hess's Law (think of using this method like systems of equations) 2. Bond enthalpy (bonds broken, +, and bonds formed, -) 3. Heat of Formation (sum of product heat of formation...
- Sat Jan 30, 2021 9:14 am
- Forum: Phase Changes & Related Calculations
- Topic: Phase Changes
- Replies: 18
- Views: 537
Re: Phase Changes
Hi! For phase changes, it's important to note that the temperature remains the same; however, the heat is either released or absorbed in the system during a phase changed.
- Sat Jan 30, 2021 9:09 am
- Forum: Phase Changes & Related Calculations
- Topic: endothermic/exothermic
- Replies: 43
- Views: 4328
Re: endothermic/exothermic
Hi! I find the best way to identify whether a phase change is endothermic or exothermic is endothermic reactions require the addition of heat, whereas exothermic reactions release heat.
- Sat Jan 30, 2021 9:06 am
- Forum: Phase Changes & Related Calculations
- Topic: when to assume x is insignificant
- Replies: 86
- Views: 6386
Re: when to assume x is insignificant
Hi! You can assume x is insignificant when the initial concentration is 1000 times larger than the Ka or Kb. If you aren't sure, the safest bet is to not assume x is insignificant.
- Thu Jan 21, 2021 1:12 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Weak vs. Strong Acids and Bases
- Replies: 9
- Views: 518
Re: Weak vs. Strong Acids and Bases
Hi! For me to remember the strong acids and bases, I find it easiest to just use quizlet/flash cards to memorize them. Since there are a lot less strong acids and bases than their weak counterparts, I would just suggest knowing the strong acids and bases rather than trying to memorize the weak acids...
- Thu Jan 21, 2021 1:10 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Ka correlation to strength of an acid
- Replies: 30
- Views: 2129
Re: Ka correlation to strength of an acid
Hi! The higher the Ka value, the stronger the acid. However, the lower the pKa value, the stronger the acid. Both mean the same but one of them just includes logarithms.
- Thu Jan 21, 2021 1:08 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Identifying Strong & Weak Acids/Bases
- Replies: 7
- Views: 236
Re: Identifying Strong & Weak Acids/Bases
Hi! Honestly, for me to remember the strong acids and bases, I just use quizlet/flash cards to memorize them. Since there are a lot less strong acids and bases than their weak counterparts, I would just suggest knowing the strong acids and bases. Strong Acids: HCl, HBr, HI, HClO3, HClO4, HNO3, H2SO4...
- Thu Jan 21, 2021 1:05 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Studying for Midterm #1
- Replies: 63
- Views: 2406
Re: Studying for Midterm #1
Hi! I would highly recommend doing the textbook problems and also reviewing sapling problems. If you have extra time or still feel a little unsure, I would go to some of the UA sessions!
- Thu Jan 21, 2021 1:04 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Solids In Reaction
- Replies: 4
- Views: 116
Re: Solids In Reaction
Hi! I believe this would result in greater product formation; however, eventually the reaction will go back to equilibrium and the K will not change.
- Thu Jan 21, 2021 1:01 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Water in Reactions
- Replies: 7
- Views: 273
Re: Water in Reactions
Hi! I believe you can use water when it is in an aqueous or gaseous form since the equilibrium constant can only be calculated with concentrations of gases or aqueous solutions.
- Thu Jan 21, 2021 12:59 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: C in ICE Box
- Replies: 19
- Views: 636
Re: C in ICE Box
Hi! I believe it just depends on the equation. If you have more of the reactant than product, the forward reaction would likely take place and as a result, the second row would be negative for the reactants and positive for the reactant. This same principle applies in reverse reactions or when there...
- Thu Jan 21, 2021 12:58 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs. Kc?
- Replies: 5
- Views: 168
Re: K vs. Kc?
Hi! K refers to the equilibrium constant and is more of a broader term for it, whereas Kc is the equilibrium constant that was calculated with molar concentrations.
- Thu Jan 21, 2021 12:55 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: How to fill in 2nd row of ICE table?
- Replies: 25
- Views: 740
Re: How to fill in 2nd row of ICE table?
Hi! It usually depends on the equation. If you have more of the reactant than product, its reasonable to assume the forward reaction would take place and the second row would be negative for the reactants and positive for the reactant. This same principle applies in reverse reactions where there is ...
- Thu Jan 21, 2021 12:52 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Percent ionization
- Replies: 13
- Views: 480
Re: Percent ionization
Hi! I believe the first equation you wrote is the correct formula.
- Sun Jan 10, 2021 10:19 am
- Forum: Ideal Gases
- Topic: Kc vs Kp
- Replies: 109
- Views: 4368
Re: Kc vs Kp
Hi! The difference is that you use Kc with concentrations/aqueous mixtures and Kp is used for pressure/ gases.
- Sun Jan 10, 2021 10:18 am
- Forum: Ideal Gases
- Topic: Sapling Homework
- Replies: 22
- Views: 876
Re: Sapling Homework
Hi! If you purchased the multi term access, you should be able to access Sapling by chose to pay with the 72 dollar credit.
- Sun Jan 10, 2021 10:16 am
- Forum: Ideal Gases
- Topic: Units of Temperature
- Replies: 82
- Views: 3343
Re: Units of Temperature
Hi! Since the standard unit of temperature is Kelvin, your answer should always be in Kelvin.
- Sun Jan 10, 2021 10:14 am
- Forum: Ideal Gases
- Topic: Units for Pressure
- Replies: 41
- Views: 2399
Re: Units for Pressure
Hi! I believe because the Standard unit for pressure is atm, we usually have to leave most answers units of atm.
- Sun Jan 10, 2021 10:12 am
- Forum: Ideal Gases
- Topic: Advice on how to navigate Chem Community
- Replies: 17
- Views: 812
Re: Advice on how to navigate Chem Community
Hi! You can post questions by going into a section for the Topic/Unit and clicking the top button that says "New Topic."
- Tue Dec 15, 2020 9:45 am
- Forum: Naming
- Topic: Aqua vs Hydrate
- Replies: 14
- Views: 930
Re: Aqua vs Hydrate
Hi! You're right: aqua refers to water when the compound is within the square brackets and hydrate refers to water outside the square brackets.
- Tue Dec 15, 2020 9:43 am
- Forum: Naming
- Topic: ONO vs. NO2
- Replies: 9
- Views: 3148
Re: ONO vs. NO2
Hi! It's the same exact structure and compound but ONO just shows the lewis structure more clearly than NO2. A similar example would be CH3CH3, which is still the same as C2H6 but just shows the lewis structure better.
Re: "ferrate"
Hi! Ferrate is only used when everything in the square brackets has a negative charge, in which normally you would just add an "-ate" to the end; however, for iron, the name is "ferrate" rather than "ironate."
- Tue Dec 15, 2020 9:40 am
- Forum: Naming
- Topic: Naming ligands directly bounded to the metal [ENDORSED]
- Replies: 4
- Views: 413
Re: Naming ligands directly bounded to the metal [ENDORSED]
Hi! Some of the more common names for ligands that aren't just named after the compound are: ammine (NH3), carbonyl (CO), and nitrosyl (NO).
- Tue Dec 15, 2020 8:59 am
- Forum: Naming
- Topic: Ligand use -ate
- Replies: 18
- Views: 967
Re: Ligand use -ate
Hi! "-ate" is added to the end of the ligand name when there is a negative charge associated with what's in the square brackets.
- Sun Dec 06, 2020 6:32 pm
- Forum: Naming
- Topic: Naming Coordination Compounds
- Replies: 5
- Views: 263
Re: Naming Coordination Compounds
Hi! I had some difficulty naming the coordination compounds but honestly, I've found that the best way to get better at naming is to do practice problems, and repeating the process allows you to memorize the steps a lot easier.
Re: Sapling 1
Hi! The ligands are named in alphabetical order, which doesn't include the prefix but the actual ligand name.
Re: Potassium
In cases of naming, it can be both. It just depends on if it's within the coordination sphere/ in the brackets or not. Usually, the ligand would have like a di-, tri-, tetra- prefix to indicate the number of ligands. But for example, K3[CoF6] is potassium-hexa-fluoro-cobaltate(III). The three potas...
- Sun Dec 06, 2020 6:24 pm
- Forum: Naming
- Topic: Anion Naming
- Replies: 7
- Views: 371
Re: Anion Naming
Hi! I think you have the right idea; we only have to use prefixes for the ligand and this rule does not apply to water molecules because they are often outside the brackets.
- Sun Dec 06, 2020 6:14 pm
- Forum: Naming
- Topic: Naming in alphabetical order?
- Replies: 10
- Views: 535
Re: Naming in alphabetical order?
Hi! Yes, the ligands are named in alphabetical order, which doesn't include the prefix but the actual ligand name.
- Thu Nov 26, 2020 9:56 am
- Forum: Electronegativity
- Topic: How is electronegativity calculated?
- Replies: 4
- Views: 243
Re: How is electronegativity calculated?
Hi! I believe Dr. Lavelle doesn't expect us to calculate electronegativity (more that we should recognize electronegative trends and elements) and the point of him mentioning the calculation was to explain that electronegativity trends are similar to electron affinity and ionization energy trends si...
- Thu Nov 26, 2020 9:53 am
- Forum: Lewis Structures
- Topic: Most Stable Structure
- Replies: 23
- Views: 3453
Re: Most Stable Structure
Hi! The most stable structures often have the lowest formal charge. AKA: it is better for one atom to have a formal charge of -1 and another to have +1 instead of one atom having a formal charge of -2 and the other to have +2. Although the compound ultimately has a charge of zero, the first structur...
- Thu Nov 26, 2020 9:51 am
- Forum: Resonance Structures
- Topic: Resonance implying electron delocalization?
- Replies: 5
- Views: 427
Re: Resonance implying electron delocalization?
Hi! I believe resonance always implies electron delocalization because delocalized electrons are electrons that are not associated with one particular bond or atom and in resonance, there are more than 1 combination of assigned single or double bonds.
- Thu Nov 26, 2020 9:46 am
- Forum: Resonance Structures
- Topic: sapling #18 wk 7/8
- Replies: 5
- Views: 428
Re: sapling #18 wk 7/8
Hi! I agree that this question was worded differently and I believe they intended for you to just find the three completely different structure (no resonance) of the same compound.
- Thu Nov 26, 2020 9:43 am
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 9
- Views: 549
Re: Resonance
Resonance is essentially the "average" or hybrid of all the different structures of the same compound, oftentimes involving the different placements of a double or triple bond.
- Sun Nov 22, 2020 1:05 pm
- Forum: Ionic & Covalent Bonds
- Topic: How to determine which molecule is more ionic?
- Replies: 11
- Views: 2413
Re: How to determine which molecule is more ionic?
Hi! I believe the method to determine whether a molecule is more ionic is to compare the electronegativity of the two elements/atoms (which can be judged qualitatively through periodic trends) and if the difference is higher, then the molecule is more ionic.
- Sun Nov 22, 2020 1:04 pm
- Forum: Octet Exceptions
- Topic: Expanded Octets
- Replies: 11
- Views: 563
Re: Expanded Octets
Hi! Octets can expand past 10 electrons. For example, atoms with electrons in the f-block (atoms in group 3 and after + periods of 6 or later).
- Sun Nov 22, 2020 1:01 pm
- Forum: Octet Exceptions
- Topic: Textbook Question 2C.3
- Replies: 4
- Views: 351
Re: Textbook Question 2C.3
Hi! Iodine can form its octet with 4 single bonds with oxygen because each bond involves 2 electrons being shared (yes all these bonds are covalent!); therefore, resulting in iodine's complete octet.
- Sun Nov 22, 2020 12:42 pm
- Forum: Octet Exceptions
- Topic: textbook 2C.3 d)
- Replies: 4
- Views: 238
Re: textbook 2C.3 d)
Hi! Because the oxygen is more electronegative, it is more willing to carry the negative formal charge. Hope this helps!
- Sun Nov 22, 2020 12:40 pm
- Forum: Octet Exceptions
- Topic: textbook 2C.3 c)
- Replies: 2
- Views: 167
Re: textbook 2C.3 c)
In addition to what the reply above said, chlorine is has a high electronegativity and once they receive an electron from oxygen (the central atom, since it has the lowest electronegativity), they have their octet. So, it would take a lot of energy for Chlorine to accept another electron from Hydrog...
- Sat Nov 14, 2020 4:02 pm
- Forum: Octet Exceptions
- Topic: Octet Rule
- Replies: 3
- Views: 180
Re: Octet Rule
Hi! The primary exceptions to the octet rule that Dr. Lavelle mentioned are radicals, elements in group 3 or higher (most notably, P, S, Cl), H, He, Li, Be, B (which can have less than 8 valence electrons).
- Sat Nov 14, 2020 3:58 pm
- Forum: Octet Exceptions
- Topic: Stability of Atoms in 3p
- Replies: 3
- Views: 219
Re: Stability of Atoms in 3p
Hi! I don't believe there is a specific numerical value that ensures stability within atoms but I believe it is based on whether the orbitals are filled, if they have 8 valence electrons, and minimizing the amount of formal charge.
- Sat Nov 14, 2020 3:56 pm
- Forum: Octet Exceptions
- Topic: Radicals
- Replies: 7
- Views: 274
Re: Radicals
Is there a way to predict which element in an atom will have the radical? this came up in textbook problem 2C.5. The radical went with Cl rather than O, and I can't explain why except for that Cl has an odd number of valence electrons to start with. Hi! I believe that the placement of the lone elec...
- Sat Nov 14, 2020 3:54 pm
- Forum: Octet Exceptions
- Topic: Identifying Radicals
- Replies: 24
- Views: 1105
Re: Identifying Radicals
Hi! The best way to identify a radical is that there will be an unpaired electron on one of the atoms.
- Sat Nov 14, 2020 3:51 pm
- Forum: Octet Exceptions
- Topic: Octet Rule Exceptions
- Replies: 8
- Views: 539
Re: Octet Rule Exceptions
Hi! For expanded octets, any atom of an element in period 3 or higher is an exception but the most commonly known ones (/the ones that one of the UA's recommended us to memorize) are P, S, and Cl. Additionally, radicals are an exception!
- Sat Nov 07, 2020 6:10 pm
- Forum: Properties of Electrons
- Topic: Elements with similar number of electrons
- Replies: 9
- Views: 292
Re: Elements with similar number of electrons
Hi! The groups in the periodic table and the format of the periodic table itself is designed to group elements with the same valence electrons and increasing valence electrons from left to right. Since they have the same valence electrons, usually the groups will have similar properties.
- Sat Nov 07, 2020 6:07 pm
- Forum: SI Units, Unit Conversions
- Topic: Memorizing SI Units
- Replies: 14
- Views: 2459
Re: Memorizing SI Units
Hi! I think you can memorize them just to make it easier for yourself but some of the conversions are actually on the reference sheet! If you don't end up memorizing them yourself, I find that oftentimes I gradually start memorizing the numbers and conversions.
- Sat Nov 07, 2020 6:04 pm
- Forum: SI Units, Unit Conversions
- Topic: Using a Calculator
- Replies: 10
- Views: 422
Re: Using a Calculator
I also want to mention that it's important to pay attention to the number of paratheses you have because sometimes it can result in syntax errors.
- Sat Nov 07, 2020 5:58 pm
- Forum: SI Units, Unit Conversions
- Topic: SI Unit for Mass
- Replies: 10
- Views: 644
Re: SI Unit for Mass
Hi! The SI unit for Mass is kilograms, so I would just assume that the equation uses kilograms unless otherwise stated (e.g. the final units has g instead of kg).
- Sat Nov 07, 2020 5:53 pm
- Forum: SI Units, Unit Conversions
- Topic: Modules This Week
- Replies: 9
- Views: 553
Re: Modules This Week
Hi! I don't think there will be any more modules, but hopefully, he sees how much we truly appreciate them and will post more!
- Fri Oct 30, 2020 5:04 pm
- Forum: Properties of Electrons
- Topic: Electron Spin
- Replies: 7
- Views: 255
Re: Electron Spin
Hi! Typically, the first electron has a positive spin; however, this concept is arbitrary so technically you can have the first electron have any spin as long as the next electron has the opposite spin.
- Fri Oct 30, 2020 5:01 pm
- Forum: Properties of Electrons
- Topic: Sapling hw #13
- Replies: 3
- Views: 129
Re: Sapling hw #13
Hi! For this problem, you need to utilize the kinetic energy equation (1/2mv^2) to find the electron's energy. To find the velocity, you need to use de Broglie's equation (lambda equals h/p) and since momentum (p) is mass times velocity, you can rearrange this equation in order to find the velocity.
- Fri Oct 30, 2020 4:58 pm
- Forum: Properties of Electrons
- Topic: Photon/ Electron Interaction
- Replies: 5
- Views: 124
Re: Photon/ Electron Interaction
Hi! If a photon does not have enough energy to excite an electron, nothing happens so the light just passes through.
- Fri Oct 30, 2020 4:57 pm
- Forum: Properties of Electrons
- Topic: Sapling #11
- Replies: 6
- Views: 520
Re: Sapling #11
Hi Emily! l is a quantum number; it is well known to be found with the formula n-1 and essentially describes the sub-shell that the electron is occupying. For example, if the electron is located in 3d, the quantum number l would be 2.
- Fri Oct 30, 2020 4:50 pm
- Forum: Properties of Light
- Topic: Is c always the speed of light?
- Replies: 92
- Views: 4923
Re: Is c always the speed of light?
In this class, I believe we only need to know c as the speed of light (given as 2.998E-8 m/s on the reference sheet).
- Thu Oct 22, 2020 6:36 pm
- Forum: SI Units, Unit Conversions
- Topic: Rounding answers
- Replies: 44
- Views: 2225
Re: Rounding answers
Hi! I would suggest NOT rounding any calculated value until you find the answer, preventing calculation errors, and when you get your answer, round your answer to the smallest sig fig. Hope this helps!
- Thu Oct 22, 2020 6:33 pm
- Forum: SI Units, Unit Conversions
- Topic: Given Unit Conversions?
- Replies: 6
- Views: 186
Re: Given Unit Conversions?
Hi! I believe we are not expected to memorize most conversions because Dr. Lavelle emphasized a more application-based learning rather than pure memorization. However, we are given most constants (Planck's , Rydberg's, etc) so there's no need to memorize those either.
- Thu Oct 22, 2020 6:31 pm
- Forum: SI Units, Unit Conversions
- Topic: unit conversions
- Replies: 24
- Views: 1147
Re: unit conversions
Hi! I think it would be best to leave your numbers in 10^x/scientific notation form just because it preserves the sig figs and also prevents you from getting confused. Hope this helps!
- Thu Oct 22, 2020 6:29 pm
- Forum: SI Units, Unit Conversions
- Topic: HW Question 1B. 21 Do we need to know the conversion between meters and miles?
- Replies: 4
- Views: 166
Re: HW Question 1B. 21 Do we need to know the conversion between meters and miles?
Hi! I believe we do not need to memorize most conversions (e.g. meters to miles) because Professor Lavelle said he's primarily going to test us on our application of content rather than pure memorization.
- Thu Oct 22, 2020 6:27 pm
- Forum: SI Units, Unit Conversions
- Topic: Do I need to do very single textbook question on the syllabus?
- Replies: 34
- Views: 1427
Re: Do I need to do very single textbook question on the syllabus?
Hey! I think you should definitely do a few textbook questions in each section just to make sure that you understand the content and can apply it. However, this isn't required but rather recommended!
- Tue Oct 13, 2020 7:54 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Textbook Homework E9
- Replies: 6
- Views: 182
Re: Textbook Homework E9
Hi! I believe Dr. Lavelle has said that this class is more focused on the application of content rather than just memorization, so I don't think we necessarily need to memorize compounds or how to name them just yet.
- Tue Oct 13, 2020 7:51 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test Accuracy
- Replies: 13
- Views: 714
Re: Test Accuracy
Hi! My rule of thumb for sig figs is usually to identify the number of sig figs in the given values and go with the smallest number of sig figs. My TA also suggested that we should try to have at least one decimal place.
- Tue Oct 13, 2020 7:49 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: for test 1
- Replies: 14
- Views: 829
Re: for test 1
Hi! I believe Dr. Lavelle has emphasized that we should try to be learning to apply our knowledge rather than just memorization, so I would just suggest for you to have a general understanding.
- Tue Oct 13, 2020 7:46 pm
- Forum: SI Units, Unit Conversions
- Topic: How to Show Your Work
- Replies: 16
- Views: 464
Re: How to Show Your Work
Hi! Even though it's not required for you to show work, I think it's better for you to just to prevent yourself from making mistakes (in unit conversion especially!). Also it's good for when you want to look back on your old work and truly understand your own thought process.
- Tue Oct 13, 2020 7:09 pm
- Forum: SI Units, Unit Conversions
- Topic: Chemistry Review Section E
- Replies: 4
- Views: 427
Re: Chemistry Review Section E
Hi! Formula units are salts or ionic compounds, and referring to formula units (ionic compounds) is the same as referring to molecules (covalent bonded compounds).
- Wed Oct 07, 2020 3:32 pm
- Forum: SI Units, Unit Conversions
- Topic: Textbook
- Replies: 22
- Views: 613
Re: Textbook
Hi! You can access the Sapling Homework with a free trial; however, I would be mindful that the free trials only last 14 days and our first Sapling assignment is due on Sunday night (10/11) @ 11:59
- Wed Oct 07, 2020 3:28 pm
- Forum: SI Units, Unit Conversions
- Topic: Sig Fig Rules
- Replies: 7
- Views: 739
Re: Sig Fig Rules
Hi! If you're still having difficulty in Sig Figs, I would highly recommend watching Organic Chemistry Tutor's Video on Sig Figs (https://www.youtube.com/watch?v=l2yuDvwYq5g); he provides the rules as well as some additional practice and goes over the problems!
- Wed Oct 07, 2020 3:20 pm
- Forum: SI Units, Unit Conversions
- Topic: Sapling Week 1 HW_problem #10
- Replies: 8
- Views: 349
Re: Sapling Week 1 HW_problem #10
It could have marked your answer wrong because they wanted you to use the non-rounded theoretical yield to find the percent yield? I'm not sure if this is the case but just a guess :))
- Wed Oct 07, 2020 3:14 pm
- Forum: SI Units, Unit Conversions
- Topic: Including the units when solving
- Replies: 8
- Views: 214
Re: Including the units when solving
I believe it is usually easier for the grader to follow your work if you add units (and if they can't follow your work --> points off) and I think it's good to try to always include units in your work because it prevents a lot of mistakes!
- Wed Oct 07, 2020 3:12 pm
- Forum: SI Units, Unit Conversions
- Topic: Sapling Assignment 1 Question 6
- Replies: 16
- Views: 404
Re: Sapling Assignment 1 Question 6
Hi! So you have to first convert the grams of CuNO3 to moles, which can be done by dividing the grams of CuNO3 by the molar mass of CuNO3. The units for this operation would be grams divided by grams/moles; therefore, you would be left with moles as the unit. Afterward, with the moles of CuNO3 that ...