Search found 81 matches

by Prasanna Padmanabham 4I
Tue Feb 11, 2020 8:10 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: HW 41.5
Replies: 2
Views: 19

HW 41.5

Hello, I am really stuck on this problem. I would super appreciate it if someone could please help me solve it. 4I.5 Suppose that 50.0 g of water at 20.0 8C is mixed with 65.0 g of water at 50.0 8C at constant atmospheric pressure in a thermally insulated vessel. Calculate ΔS and ΔS (total) for the ...
by Prasanna Padmanabham 4I
Sun Feb 09, 2020 11:55 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: HW 4D7
Replies: 4
Views: 19

Re: HW 4D7

For gases, the change in enthalpy is defined by that equation. This is because when gas is produced work is done to clear the other gases so the enthalpy is lower than the internal energy. This is explained in detail on pg 274 in the textbook (4D.2)
by Prasanna Padmanabham 4I
Sun Feb 09, 2020 11:47 pm
Forum: Calculating Work of Expansion
Topic: q=C delta T
Replies: 5
Views: 22

Re: q=C delta T

Alexis Robles 2k wrote:when should we use the m/n in the equation?


Did mean to type: q=n*CdeltaT

If so, n refers to mols while m refers to grams...you would use whatever units the question asked for...
by Prasanna Padmanabham 4I
Sun Feb 09, 2020 11:41 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Boltzmann equation
Replies: 5
Views: 24

Re: Boltzmann equation

The Boltzmann equation is giving the residual entropy of the system. Entropy is the amount of "disorder" and the Boltzmann equation is sort of giving a statistical answer of all the possible orientations and positions of all the molecules in the system.
by Prasanna Padmanabham 4I
Sun Feb 09, 2020 11:36 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Question 4B.3
Replies: 5
Views: 20

Re: Question 4B.3

Thank you guys for your replies! I used the answer key at the back of the book (I don't have the solution manual) and it said 90 * 10^2 J...I think that the answer key in the book is wrong since the solution manual also says 490.
by Prasanna Padmanabham 4I
Sun Feb 09, 2020 11:33 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Reversible Reactions vs. Irreversible Reactions
Replies: 6
Views: 22

Re: Reversible Reactions vs. Irreversible Reactions

I feel like it wouldn't hurt to know...there were a few graph questions on the 14A midterm and final last quarter...
by Prasanna Padmanabham 4I
Fri Feb 07, 2020 9:08 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Question 4B.3
Replies: 5
Views: 20

Question 4B.3

Hello, I got the first part of this question right, but not the second, I was curious if someone could help me figure out what I'm missing. Thank you! The internal energy of a system increased by 982 J when it was supplied with 492 J of energy as heat. (a) Was work done by or on the system? (b) How ...
by Prasanna Padmanabham 4I
Fri Feb 07, 2020 8:41 pm
Forum: General Science Questions
Topic: Midterm
Replies: 17
Views: 152

Re: Midterm

Ben 1B wrote:Does anyone know if we will be able to take a practice midterm before the actual midterm?


The UAs made a practice midterm for us this quarter. Search up Pizza Rolls and you should find it.
by Prasanna Padmanabham 4I
Sun Feb 02, 2020 8:06 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: U
Replies: 4
Views: 24

Re: U

You should watch this video for an introduction to internal energy and U

https://www.khanacademy.org/science/physics/thermodynamics/laws-of-thermodynamics/v/more-on-internal-energy
by Prasanna Padmanabham 4I
Sun Feb 02, 2020 7:27 pm
Forum: General Science Questions
Topic: Midterm
Replies: 17
Views: 152

Re: Midterm

Does anyone know if all the thermochemistry and thermodynamic equations will be supplied on the midterm? Dr. Lavelle is usually really nice about the equations and provides everything you would need. I'm pretty sure he uses the same equation sheet for all the tests so you can take a look at test 1....
by Prasanna Padmanabham 4I
Sun Feb 02, 2020 7:19 pm
Forum: General Science Questions
Topic: Midterms
Replies: 22
Views: 136

Re: Midterms

The outlines are a great resource to find practice problems and use as a study plan/guide. Additionally, attending all the (one per each topic) review sessions will also help you figure out what material will be covered and where you are. Sometimes the textbook can feel a bit too broad. I'm pretty s...
by Prasanna Padmanabham 4I
Sun Feb 02, 2020 7:13 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Positive or negative work?
Replies: 8
Views: 29

Re: Positive or negative work?

I think about the same as I think about endothermic or exothermic reactions. If heat is being released by the system, enthalpy (delta H) is negative and like that, if the system is doing work, then the work is negative. If the system needs heat then the enthalpy (delta H) sign is positive, and if so...
by Prasanna Padmanabham 4I
Sun Feb 02, 2020 7:02 pm
Forum: General Science Questions
Topic: Midterm
Replies: 17
Views: 152

Re: Midterm

hopefully Lyndon, the UA will make us a practice midterm :/...
The one he made for 14A last quarter was really helpful and I really appreciated it :).
by Prasanna Padmanabham 4I
Mon Jan 27, 2020 12:07 pm
Forum: Student Social/Study Group
Topic: Chemical Bonding Recording
Replies: 1
Views: 18

Chemical Bonding Recording

I found a really interesting article/video in my newsfeed. Recently, scientists published their experiment showing/recording of chemical bonds forming and breaking. Here is the link to the article if you all want to watch the too :) https://www.sciencenews.org/article/dance-two-atoms-reveals-chemica...
by Prasanna Padmanabham 4I
Sun Jan 26, 2020 5:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pH
Replies: 7
Views: 34

Re: pH

It really depends on what information you are given, I feel like for most problems this is how I've been dealing with it...
1) convert pKa to Ka
Ka = 10^(-pKa)
2) write Ka concentration out and figure out [H+]
3) plug into pH = -log [H+]
by Prasanna Padmanabham 4I
Thu Jan 23, 2020 12:16 pm
Forum: Calculating the pH of Salt Solutions
Topic: Problem 6D.15
Replies: 2
Views: 31

Re: Problem 6D.15

Follow up question: I am still very stuck on this problem, can someone please post a step-by-step of the solution?
Thank you so much!
by Prasanna Padmanabham 4I
Tue Jan 21, 2020 8:07 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Chemical Equilibrium Part 4 Question 13
Replies: 3
Views: 17

Re: Chemical Equilibrium Part 4 Question 13

I would assume that i is neither since the moles are equal on both sides. The pressure increases with the volume decreasing so the chemical reaction would favor the side with less moles but that is not an option. I didn't see this at first either, but the I2 in the products has an (s) next to it, s...
by Prasanna Padmanabham 4I
Tue Jan 21, 2020 7:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test #1
Replies: 2
Views: 23

Re: Test #1

Well, if Ka is less than 10^-3, then you are usually safe to approximate. In the end, though, you typically need to make sure that x is less than 5% of the initial concentration. If it is less than 5%, you are good, if it's not, you need to redo the problem. For the test specifically, I'm not sure i...
by Prasanna Padmanabham 4I
Tue Jan 21, 2020 7:53 pm
Forum: Calculating the pH of Salt Solutions
Topic: Problem 6D.15
Replies: 2
Views: 31

Problem 6D.15

Hi Everyone, I am having a really hard time with this problem. I would appreciate if someone can please let me know what I'm doing wrong. 6D.15 Calculate the pH of (a) 0.19 m NH4Cl(aq); (b) 0.055 m AlCl3(aq). For part B) is the equation: AlCl3 <==> Al (OH-)3 + 3HCl. The 3HCl then dissociates complet...
by Prasanna Padmanabham 4I
Sat Jan 18, 2020 9:57 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constant Units
Replies: 4
Views: 19

Re: Equilibrium Constant Units

Dr. Lavelle, in the lecture, talked about how Kc should technically be measured by how much "activity" is occurring in the equation. So how much activity that is produced by the forward reaction and how much activity is produced by the reverse reaction. Since it is a bit hard to measure th...
by Prasanna Padmanabham 4I
Sat Jan 18, 2020 9:51 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5 %
Replies: 4
Views: 16

Re: 5 %

I was doing a homework problem and I was using my calculator's quadratic function to solve the Kc equations. The funny part, I guess, is that my x value was so small that when I subtracted it from the initial value the first two digits/numbers were still the same. When you have two (or three) signif...
by Prasanna Padmanabham 4I
Sat Jan 18, 2020 9:43 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5.39
Replies: 1
Views: 10

Re: 5.39

The volume was halved. So initially, you had 0.020 mols/Liter and now you have 0.020 mols/0.5Liters = 0.040 M. Equilibrium concentration, values when trying to find Kc, deal with values in mols/Liter or molarity.
by Prasanna Padmanabham 4I
Thu Jan 16, 2020 10:16 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5l.29
Replies: 5
Views: 24

Re: 5l.29

I have a followup question: Why did you all decide to set x = to change in equilibrium for H2 or Cl2, and 2X = change in HCL instead of saying x = change in HCL and 0.5X = change in H2 and Cl2? I did it the second way and I got the wrong answer. I'm trying to understand conceptually why my way is wr...
by Prasanna Padmanabham 4I
Wed Jan 15, 2020 10:41 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Writing K for heterozygous reactions
Replies: 5
Views: 17

Writing K for heterozygous reactions

Hello,
If there was an equation with liquids and gases in products and/or reactants side, how would you write Kc? Would you include both liquids and gases in it or only the gases or do you write two separate equations?
by Prasanna Padmanabham 4I
Mon Jan 13, 2020 11:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6A.19
Replies: 6
Views: 46

Re: 6A.19

that's confusing...hmm...did it say millimolars? I'm interested in an answer too...
by Prasanna Padmanabham 4I
Mon Jan 13, 2020 11:37 pm
Forum: Ideal Gases
Topic: When to use this equation
Replies: 14
Views: 68

Re: When to use this equation

This equation is super versatile. If you know a few variables and you are trying to figure out how to represent ideal gases differently, then, you can just rearrange the equation. For example, if you have the pressure of a gas, but want to know what the concentration of the gas is you just need to r...
by Prasanna Padmanabham 4I
Mon Jan 13, 2020 11:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Updating my account
Replies: 2
Views: 18

Updating my account

Hello
I was in Dr. Lavelle's class (14A) last quarter, and I was curious if I had to do something to "update" my account to make sure I'm getting credit for participating in 14B class.
Thank you!
by Prasanna Padmanabham 4I
Mon Jan 13, 2020 11:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5J.5
Replies: 4
Views: 20

Re: 5J.5

I can answer why there is no change from the increase in pressure. Usually, in a Kp equation, the partial pressure is representative of the number of mole/concentrations of a substance at a certain temperature and volume. You can think of it as how much "stuff" is there increases with pres...
by Prasanna Padmanabham 4I
Fri Jan 10, 2020 4:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Exercise 5G.1
Replies: 4
Views: 16

Re: Exercise 5G.1

c) if one starts with a higher pressure of reactant, the equilibrium constant will be larger This is false because the equilibrium constant will stay the same for reactions happening at the same temperature. Having a "greater pressure" of the reactant will affect or cause a shift to the le...
by Prasanna Padmanabham 4I
Sat Dec 07, 2019 7:13 pm
Forum: Naming
Topic: -ate, -ide, -ite, -o
Replies: 3
Views: 31

Re: -ate, -ide, -ite, -o

According to the textbook, for any anion inside the [ ] (so any anion directly bonded to the central metal cation), the ending should be an -ato or an -ido or an -ito. For example, the Chloride anion is written as chlorido.
by Prasanna Padmanabham 4I
Sat Dec 07, 2019 7:06 pm
Forum: Conjugate Acids & Bases
Topic: 6C.17
Replies: 2
Views: 27

Re: 6C.17

I believe its because there is a negative charge on the BrO- molecule.
by Prasanna Padmanabham 4I
Sat Dec 07, 2019 6:51 pm
Forum: Naming
Topic: Latin Names
Replies: 3
Views: 25

Re: Latin Names

I'm pretty sure many of the elements have Latin names or come from Latin words. You just need to memorize that Iron is written as ferrate if a coordination molecule is negative.
by Prasanna Padmanabham 4I
Sat Dec 07, 2019 9:55 am
Forum: Photoelectric Effect
Topic: Midterm Question 4
Replies: 1
Views: 35

Re: Midterm Question 4

Those are the same answers I got (and I got the answer correctly). En= Eupper - Elower, but En= - hR/n^2, so when you plug it in you would get: En = -Eupper - (-E lower) so En=-Eupper + Elower. Since as n increases, En get closer to 0, and as n gets smaller, En decreases (remember big negative numbe...
by Prasanna Padmanabham 4I
Fri Dec 06, 2019 12:26 am
Forum: Identifying Acidic & Basic Salts
Topic: Electrons and pH
Replies: 2
Views: 23

Re: Electrons and pH

When the equation is NH4+ + H2O --> NH3 + H3O+
You notice how the NH4 is donating a Hydrogen. pH is the -log[H+] so as the concentration of H+ increases, then the pH decreases. NH4+ is a proton donator and therefore the concentration of H+ increases which then decreases the pH.
by Prasanna Padmanabham 4I
Wed Dec 04, 2019 8:39 pm
Forum: Identifying Acidic & Basic Salts
Topic: Lecture
Replies: 3
Views: 26

Re: Lecture

Cl- does not affect the pH of a solution because Cl- is a really stable atom; it does not need to bind to a Hydrogen. While NH3- is a weak base so it's conjugate acid, NH4 will lose a few Hydrogens in the NH4 and act as an acid by donating its extra Hydrogen.
by Prasanna Padmanabham 4I
Sat Nov 30, 2019 12:25 pm
Forum: General Science Questions
Topic: test taking nervousness
Replies: 19
Views: 166

Re: test taking nervousness

I feel you! I do the easier problems first because it makes me feel better (psychologically) and then I try to the harder problems. Think about what you do know because chances are you do know a lot. Maybe, if you can, identify what chapter the question is from and write down all the equations you k...
by Prasanna Padmanabham 4I
Sat Nov 30, 2019 11:59 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Explain VSEPR conceptually
Replies: 12
Views: 52

Re: Explain VSEPR conceptually

VSPER stands for Valence shell electron pair repulsion theory. While lewis structures are helpful to figure out single/double bonds and the number of lone pairs etc. VSPER takes electron pair repulsions into considerations and allows us to think about the 3D shape of the molecule.
by Prasanna Padmanabham 4I
Sat Nov 30, 2019 11:55 am
Forum: Bronsted Acids & Bases
Topic: Net Ionic Equations
Replies: 5
Views: 33

Re: Net Ionic Equations

Do you have a specific example or a specific problem you are stuck on? I'm not quite sure how to answer your question broadly...
by Prasanna Padmanabham 4I
Sat Nov 30, 2019 11:51 am
Forum: Resonance Structures
Topic: Molecules with resonance
Replies: 4
Views: 51

Re: Molecules with resonance

Those with resonance structures are weaker acids because it is harder for the hydrogen atoms to "break off" because the negative formal charge is distributed throughout so resonance structures are more stable.
by Prasanna Padmanabham 4I
Sat Nov 30, 2019 11:49 am
Forum: Amphoteric Compounds
Topic: 6A.11
Replies: 2
Views: 22

Re: 6A.11

HPO4(2-) as an acid: PO4(3-) (conjugate base)
HPO4 (2-) as a base: H2PO4 (-1) (conjugate acid)...
by Prasanna Padmanabham 4I
Fri Nov 29, 2019 10:31 pm
Forum: Dipole Moments
Topic: Polar or nonpolar?
Replies: 4
Views: 64

Re: Polar or nonpolar?

I know this video isn't really for the exact same molecule, but they are similar and you can use the same "technique" to analyze the polarity of CH2Br2

[youtube]https://www.youtube.com/watch?v=As-hcYY8Yaw[/youtube]
by Prasanna Padmanabham 4I
Fri Nov 29, 2019 10:25 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Example 6A.2
Replies: 1
Views: 31

Example 6A.2

In example 6A.2 in the textbook, the question is: Barium hydroxide is a base that is sometimes used for titrating acids. When using it, you need to know the actual concentration of hydroxide ion in the solution. What are the molar concentrations of H3O1+ and OH2- in 0.0030 m Ba(OH)2(aq) at 25 C? In ...
by Prasanna Padmanabham 4I
Sun Nov 17, 2019 5:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole moment
Replies: 5
Views: 33

Re: Dipole moment

The dipole moment is basically when a partially negatively charged atom in a polar covalent bond is attracted to another positively charged thing (usually the positively charged atom of another polar covalent bond or a cation). This isn't like a bond, but there is a very weak, but still significant ...
by Prasanna Padmanabham 4I
Sun Nov 17, 2019 5:44 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: bond order calculations
Replies: 4
Views: 38

Re: bond order calculations

I believe bond order just refers to the number of bonds between two atoms (single bonds, double bonds, triple bonds etc.) so I would just draw a lewis structure and count... https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Th...
by Prasanna Padmanabham 4I
Sun Nov 17, 2019 5:41 pm
Forum: Electronegativity
Topic: Bond type for FeO2?
Replies: 3
Views: 37

Re: Bond type for FeO2?

I guess it officially described as being "polar covalent" but its super ionic in character.
by Prasanna Padmanabham 4I
Sun Nov 17, 2019 5:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Grading
Replies: 7
Views: 71

Re: Grading

I would imagine so, but I would be interested in knowing how he curves the class considering the fact that the average score on the last midterm was like a high 70%...
by Prasanna Padmanabham 4I
Sun Nov 17, 2019 5:37 pm
Forum: Student Social/Study Group
Topic: What will Test 2 be on?
Replies: 8
Views: 47

Re: What will Test 2 be on?

I understand, but what sort of specific questions might he ask? What textbook problems should I do? I feel like we did a lot of theory so I'm not sure what sort of questions I should be prepared for...
by Prasanna Padmanabham 4I
Sun Nov 17, 2019 5:23 pm
Forum: Student Social/Study Group
Topic: What will Test 2 be on?
Replies: 8
Views: 47

What will Test 2 be on?

Can someone please direct me towards what lessons/pages I should read to prepare for Test 2?
by Prasanna Padmanabham 4I
Wed Nov 13, 2019 9:45 pm
Forum: Administrative Questions and Class Announcements
Topic: Test #2
Replies: 22
Views: 243

Re: Test #2

Well my discussion is on Wednesday and I'm really nervous....can someone please post specific textbook sections we should study for the test?

Thank you!
by Prasanna Padmanabham 4I
Tue Nov 05, 2019 7:27 pm
Forum: Lewis Structures
Topic: Homework Problem 2C. 3c
Replies: 1
Views: 17

Re: Homework Problem 2C. 3c

It looks like your Hydrogen is bonded directly to the Chlorine, but its almost always attached to an Oxygen with acids and (bases too I think)...
by Prasanna Padmanabham 4I
Tue Nov 05, 2019 7:22 pm
Forum: Octet Exceptions
Topic: Did I summarize the octet rule exception correctly?
Replies: 1
Views: 26

Did I summarize the octet rule exception correctly?

So basically, when drawing Lewis Structures, the first goal should be to get the smallest formal charge for all the atoms. Does this mean that I should give double bonds to structures even if it means breaking the octet rule if it means that all the atoms in the molecule will have a formal charge of...
by Prasanna Padmanabham 4I
Tue Nov 05, 2019 6:48 pm
Forum: Octet Exceptions
Topic: Naming molecules
Replies: 2
Views: 33

Naming molecules

For the midterm, do you think we need to know how ions are named? For example in HW problem 2C.3, they gave the name of the ion/molecule (instead of the molecular formula) and asked us to draw a Lewis structure. Do you think that's how the midterm is going to be or do you know if we will get a molec...
by Prasanna Padmanabham 4I
Sun Nov 03, 2019 2:57 pm
Forum: Dipole Moments
Topic: Dipole Moment Significance
Replies: 1
Views: 19

Re: Dipole Moment Significance

Dipole moment exists for any covalently bonded molecules where the atoms have different electronegativities. This is because one atom will exert a stronger force on the electrons and "hog" the electrons from the less electronegative atom. Therefore, the dipole moment exists when there is a...
by Prasanna Padmanabham 4I
Sun Nov 03, 2019 2:48 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 1E.13
Replies: 2
Views: 18

Re: 1E.13

You should watch this video by Bozeman Science: https://www.youtube.com/watch?v=2AFPfg0Como. The first 7 minutes are an intro to what the different subshells and energy levels are, but he talks about writing electron configurations at the 7-minute mark.
by Prasanna Padmanabham 4I
Sun Nov 03, 2019 2:40 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic and Covalent Character
Replies: 2
Views: 22

Re: Ionic and Covalent Character

So there is a progressive scale of bonds that ranges from ionic to covalent. For example, if two atoms with really different electron affinities share "electrons" sometimes, electrons might hang out with the atom with more electron affinity (like the Oxygen side of H2O being a bit more neg...
by Prasanna Padmanabham 4I
Sun Nov 03, 2019 10:11 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Quantum Numbers and subshells
Replies: 2
Views: 19

Quantum Numbers and subshells

Hello, I have a question about what subshells "l" numbers are. For example if n=3, then l = 0, 1, 2 or basically l = 0,1,2...n-1. Then if n = 5, then l = 0,1,2,3,4 right? So if an "l" value of 0 corresponds to the "s" subshell, 1 corresponds to the "p" subshel...
by Prasanna Padmanabham 4I
Sun Nov 03, 2019 1:12 am
Forum: Trends in The Periodic Table
Topic: Units for energy
Replies: 1
Views: 23

Re: Units for energy

The standard unit used for kinetic energy is "Joules." For ionization energy, it is measured in Kilo Joules/mole or ElectroVolts. The units are all measuring the same thing, but the scale is different. For example, you can use inches, millimeters or even miles to measure different lengths,...
by Prasanna Padmanabham 4I
Sun Oct 27, 2019 10:33 pm
Forum: Resonance Structures
Topic: Resonance
Replies: 3
Views: 39

Re: Resonance

I'm pretty sure you usually just have to draw like one of the structures (unless specifically asked to draw all).
by Prasanna Padmanabham 4I
Sun Oct 27, 2019 10:31 pm
Forum: Octet Exceptions
Topic: Octet Guideline?
Replies: 2
Views: 18

Re: Octet Guideline?

I'm not sure what exactly you are asking clarification for, but the reason why we use the octet rule is that it usually works for the elements in the first two columns and the last six columns (well noble gases don't really react with anything because they have full octet) of the periodic table. Thr...
by Prasanna Padmanabham 4I
Sun Oct 27, 2019 10:22 pm
Forum: Quantum Numbers and The H-Atom
Topic: H atom
Replies: 3
Views: 32

Re: H atom

That's a really interesting question. I think it is because that Hydrogen is a really simple atom with one proton and one electron (which makes examples easier), but I'm curious to hear what other people have to say.
by Prasanna Padmanabham 4I
Sun Oct 27, 2019 10:17 pm
Forum: Ionic & Covalent Bonds
Topic: electron configuration
Replies: 5
Views: 44

Re: electron configuration

For a list of atoms with different electron configurations check this website out: [url]https://www.scribd.com/doc/13771509/Electron-Configurations-of-Elements-Which-Are-Exceptions-to-the-Rule
[/url]
by Prasanna Padmanabham 4I
Sun Oct 27, 2019 9:32 pm
Forum: Ionic & Covalent Bonds
Topic: What is the difference between an anion and cation?
Replies: 7
Views: 41

Re: What is the difference between an anion and cation?

anions are ions that are negatively charged (have more electrons than normal), and cations are those that are positively charged (have less electrons than normal).
by Prasanna Padmanabham 4I
Sun Oct 27, 2019 7:11 pm
Forum: *Shrodinger Equation
Topic: schrodinger equation
Replies: 2
Views: 25

Re: schrodinger equation

Will do, Thank you!
by Prasanna Padmanabham 4I
Sun Oct 27, 2019 6:38 pm
Forum: *Shrodinger Equation
Topic: schrodinger equation
Replies: 2
Views: 25

schrodinger equation

Hello, I am having trouble understanding the Schrodinger equation and lesson 1C in general, do you all have any videos or articles you recommend?
by Prasanna Padmanabham 4I
Sun Oct 20, 2019 7:33 pm
Forum: Properties of Electrons
Topic: stern and Gerlach
Replies: 1
Views: 25

Re: stern and Gerlach

This video is really informative (and animations are cute). https://www.youtube.com/watch?v=cd2Ua9dKEl8, it goes over spin and the Stern and Gerlach experiment and why it is important.
by Prasanna Padmanabham 4I
Sun Oct 20, 2019 7:27 pm
Forum: Quantum Numbers and The H-Atom
Topic: spin magnetic quantum #
Replies: 2
Views: 15

Re: spin magnetic quantum #

The signs don't really matter, the -/+ or the "up" and "down" For the subshells, you can only have like a 1/2 or a -1/2 or up and down but you can't really have like two positive spins electrons in the same subshell or two negative spins electrons in the same subshell -- they nee...
by Prasanna Padmanabham 4I
Sun Oct 20, 2019 7:22 pm
Forum: Quantum Numbers and The H-Atom
Topic: Yet Another Electron Spin Question
Replies: 5
Views: 71

Re: Yet Another Electron Spin Question

That a really good question and I'm looking forward to an answer too
by Prasanna Padmanabham 4I
Sun Oct 20, 2019 7:00 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Advice for studying
Replies: 58
Views: 544

Re: Advice for studying

I agree with everyone here. I am not a auditory learner, so I forget concepts when I just listen to someone explain it. I find it extremely helpful to read the textbook and do every single example problem . This is really helpful because when I'm doing HW problems, I like to classify the problem and...
by Prasanna Padmanabham 4I
Sun Oct 20, 2019 6:50 pm
Forum: Quantum Numbers and The H-Atom
Topic: Spin numbers
Replies: 4
Views: 47

Re: Spin numbers

Electrons do spin, but the "up" and "down" -1/2 or +1/2 spin-orientation doesn't really matter, as long as you are consistent/mindfull of the antiparallel and parallel spinning. For more information, you should read this article: https://www.chemicool.com/definition/electron_spin...
by Prasanna Padmanabham 4I
Sun Oct 13, 2019 12:05 am
Forum: Photoelectric Effect
Topic: threshold energy
Replies: 6
Views: 33

Re: threshold energy

In order for the electron to be excited it needs a very specific amount of energy. If it gets "too much" or "too little" it cannot move up to a certain energy level. For example, an electron needs a very specific amount of energy to go from the 1st energy level to the 2nd. Since ...
by Prasanna Padmanabham 4I
Sat Oct 12, 2019 11:59 pm
Forum: DeBroglie Equation
Topic: Learning Objective
Replies: 1
Views: 46

Re: Learning Objective

This video does a really good job explaining it: https://www.youtube.com/watch?v=cYyFPFU6s_A
by Prasanna Padmanabham 4I
Sat Oct 12, 2019 11:57 pm
Forum: Photoelectric Effect
Topic: Mass of Electron
Replies: 6
Views: 45

Re: Mass of Electron

In summary, electrons don't weigh a lot in comparison to protons or neutrons and thats why electron masses are "ignored" when thinking about molar masses. But since you asked electrons weigh about: 9.109×10−31 kilograms or 5.489×10−4 atomic mass units.
by Prasanna Padmanabham 4I
Sat Oct 12, 2019 11:54 pm
Forum: Properties of Light
Topic: wavelike properties
Replies: 6
Views: 39

Re: wavelike properties

I'm not quite sure why electrons "need" to have wavelike properties, but I can say that through experimentation and mathematical models, scientists predict that electrons are a particle with wave-like properties.
by Prasanna Padmanabham 4I
Sat Oct 12, 2019 11:52 pm
Forum: Properties of Light
Topic: Large Objects
Replies: 7
Views: 53

Re: Large Objects

Well if you take a look at the De Broglie's formula WaveLength = H/mass*velocity, as mass increases the wavelength is so small that it basically doesn't look or behave like a wave.
by Prasanna Padmanabham 4I
Tue Oct 01, 2019 8:44 pm
Forum: Limiting Reactant Calculations
Topic: Homework Problem M.5
Replies: 2
Views: 34

Re: Homework Problem M.5

The problem: " Solve this exercise without using a calculator. The reaction 6 ClO2(g) + 2 BrF3(l) --> 6 ClO2F(s) + Br2(l) is carried out with 12 mol ClO 2 and 5 mol BrF 3 . (a) Identify the excess reactant. (b) Estimate how many moles of each product will be produced and how many moles of the e...
by Prasanna Padmanabham 4I
Tue Oct 01, 2019 8:32 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity Self test E1B
Replies: 2
Views: 26

Re: Molarity Self test E1B

3.14 mols of H2O means there are 6.28 mols of Hydrogen.
6.28 mols * 6.022 *10^23 atoms/mol = 3.78*10^24 atoms
by Prasanna Padmanabham 4I
Tue Oct 01, 2019 8:30 pm
Forum: Molarity, Solutions, Dilutions
Topic: Dilution and Molarity Questions
Replies: 8
Views: 52

Re: Dilution and Molarity Questions

Most dilution question, however wordy (or confusing the textbook might try to make it sound) they might be, come down to the M1 * V1 = M2 * V2 formula. I would try to make a list of the information given and then maybe what you don't know (which is usually just one variable) and then solve the equat...
by Prasanna Padmanabham 4I
Tue Oct 01, 2019 8:16 pm
Forum: Significant Figures
Topic: Rounding the elements
Replies: 12
Views: 115

Re: Rounding the elements

I tend to round to the nearest whole number when I'm trying to come up with like a guesstimate or if I'm doing like a multiple-choice test. For homework or free-response questions on tests, I tend to use the number on the periodic table of elements (so 1.008 for H and 15.99 for O). I round/do sig fi...
by Prasanna Padmanabham 4I
Tue Oct 01, 2019 8:08 pm
Forum: Limiting Reactant Calculations
Topic: Problem G5
Replies: 2
Views: 57

Re: Problem G5

A) The problem is asking "how much of the 250mL solution does the student need to obtain 2.15 mmol of Na+ ions?" 1. How many mols are in the 250 mL solution? a) Find molar mass of Na2CO3 which is 105.96 grams/mol b) 2.111g / 105.96g/mol = 0.0199 mols 2. Molarity of solution: 0.0199mols / 0...

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