Search found 132 matches

by Kishan Shah 2G
Mon Oct 28, 2019 10:33 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 11
Views: 144

Re: Midterm

The format should be similar to first test but longer. It will cover fundamentals, quantum, and chemical bonding.
by Kishan Shah 2G
Mon Oct 28, 2019 10:28 am
Forum: Lewis Structures
Topic: Lewis Structure of Ions
Replies: 6
Views: 66

Re: Lewis Structure of Ions

Yes make sure you place the bracket, however Dr. Lavelle stated in class that the placement of the charge whether its inside or outside the brackets does not matter.
by Kishan Shah 2G
Mon Oct 28, 2019 10:27 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Transition Metals
Replies: 2
Views: 69

Re: Transition Metals

Usually the question will denote which form of the cation it is. However another easy way to tell is to take a look at the anion it is bonded to in order to determine what the charge would have to be on the cation for the molecule to have a net neutral charge.
by Kishan Shah 2G
Wed Oct 23, 2019 10:40 pm
Forum: Lewis Structures
Topic: lewis drawings
Replies: 8
Views: 146

Re: lewis drawings

I am not sure. However, this would be a great question to ask in Dr. Lavelle's office hours.
by Kishan Shah 2G
Wed Oct 23, 2019 10:38 pm
Forum: Resonance Structures
Topic: defintion
Replies: 7
Views: 93

Re: defintion

Yes, resonance structures are molecules that can be drawn in different configurations that still represent the same molecule. The example in class today shows clearly shows the true meaning of a resonance structure.
by Kishan Shah 2G
Wed Oct 23, 2019 10:36 pm
Forum: Trends in The Periodic Table
Topic: bond length
Replies: 9
Views: 113

Re: bond length

So far I know of no way to calculate bond lengths and I don't know if Lavelle will teach us a method to. I also do not think him going over it in class today roughly means we have it know it. I think he went over it just to reinforce basic concepts.
by Kishan Shah 2G
Wed Oct 23, 2019 10:33 pm
Forum: Trends in The Periodic Table
Topic: Location of elements
Replies: 12
Views: 182

Re: Location of elements

Yes, its the best to know them and its not too hard to memorize which parts of the periodic table are solid, liquid, and gas.
by Kishan Shah 2G
Wed Oct 23, 2019 10:32 pm
Forum: Ionic & Covalent Bonds
Topic: Double Bond vs Single Bond Length
Replies: 6
Views: 150

Re: Double Bond vs Single Bond Length

Correct, the lewis structure is just a rough model and Dr. Lavelle did say that the actual length is 1.24 angstrom. The double bonds and triple bonds contain more electrons, thereby exerting a stronger force on the nuclei of the atoms and this pulls the atoms closer together hence shorter bond lengt...
by Kishan Shah 2G
Wed Oct 23, 2019 10:28 pm
Forum: SI Units, Unit Conversions
Topic: Sharing of electrons
Replies: 3
Views: 160

Re: Sharing of electrons

The concept of electrons lying on the internuclear axis is not as hard to understand as it sounds. When two atoms are sharing electrons, the electrons they are sharing, otherwise known as the electrons that are represented by bond lines in lewis structures, are shared along this axis or space that c...
by Kishan Shah 2G
Wed Oct 23, 2019 10:09 pm
Forum: Ionic & Covalent Bonds
Topic: What topic are we on?
Replies: 11
Views: 155

Re: What topic are we on?

Based on Dr. Lavelle's last email 2 weeks ago he said that as we transition from fundamentals to quantum, that transition week's homework could be from either units. I do not believe that just because he taught chemical bonds today in class that we have to turn in chemical bonds hw since people in T...
by Kishan Shah 2G
Wed Oct 23, 2019 10:04 pm
Forum: Trends in The Periodic Table
Topic: Exceptions
Replies: 3
Views: 52

Re: Exceptions

As the above two replies stated, ionization energies increase as you move toward the bottom left of the periodic table. This is due to the fact that these electrons are further away from the nucleus so they are more easily removable, and the fact that these elemental atoms have an inclination to los...
by Kishan Shah 2G
Sat Oct 19, 2019 12:03 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: HW 1D.23
Replies: 2
Views: 36

Re: HW 1D.23

The first one can have 3. The second can have 1. The third can have 4. The fourth can have 1.
by Kishan Shah 2G
Sat Oct 19, 2019 11:51 am
Forum: Einstein Equation
Topic: HW 1B.15c
Replies: 1
Views: 64

Re: HW 1B.15c

We know its kinetic energy, since the photon needs to contain enough energy to eject the electron from the surface as well as to cause it to move at 3.6 x 10^3 km*s^-1 . The energy involved, therefore, is kinetic energy. I was also confused at first on why we use Kinetic Energy, and in my opinion th...
by Kishan Shah 2G
Sat Oct 19, 2019 11:48 am
Forum: Properties of Light
Topic: Unit for Wavelength
Replies: 34
Views: 311

Re: Unit for Wavelength

Usually when you are doing calculations using the equations related to this unit and you cancel out all the units you are left with meters when you are solving for wavelength. However, a lot times the questions want you to convert this answer into nanometers since the most common way to report wavel...
by Kishan Shah 2G
Sat Oct 19, 2019 11:44 am
Forum: DeBroglie Equation
Topic: 1B.19
Replies: 1
Views: 41

Re: 1B.19

The answer for this question just ends up being that the wavelength of a proton and a neutron are identical to 3 significant figures. The solutions guide doesn't actually end calculating the final answer as a percentage of either the proton/neutron's weight. You just have to use the equation to find...
by Kishan Shah 2G
Tue Oct 15, 2019 8:18 am
Forum: DeBroglie Equation
Topic: Three Fundamental Equations
Replies: 3
Views: 59

Re: Three Fundamental Equations

The way I decide which equation to use is that I first write down all the formulas on a separate piece of paper in front of me. Then under the problem, I write down all my given values. Then I look at what value the question is asking for. Then it is easier to determine which equation(s) to use to g...
by Kishan Shah 2G
Tue Oct 15, 2019 8:15 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: HW Problem 1.A.15
Replies: 3
Views: 62

Re: HW Problem 1.A.15

The way that I approached the questions was that I used the Rydberg Equation after determining that this was an instance of the Lyman Series. So we know the frequency, we know the Rydberg constant, we know n(1)=1 due to the fact its a Lyman series. So we solve for n2. Once we determine n2, we know t...
by Kishan Shah 2G
Sat Oct 12, 2019 10:14 am
Forum: Photoelectric Effect
Topic: Energy classification
Replies: 2
Views: 20

Re: Energy classification

Yes, it is called "work function" or "threshold energy." The equation is (Energy of Incoming Photon = Energy to Remove + Excess Energy). The energy to remove an electron is indeed the threshold energy.
by Kishan Shah 2G
Sat Oct 12, 2019 10:09 am
Forum: Properties of Light
Topic: Color of Light
Replies: 2
Views: 41

Re: Color of Light

Yes, the color of light is determined by wavelength. This can be seen directly on page 6 in the textbook. There are something called spectral lines, which were discovered by Johann Balmer, that are light rays that are emitted when electrons are excited from one energy level to the next. The color of...
by Kishan Shah 2G
Sat Oct 12, 2019 10:05 am
Forum: General Science Questions
Topic: Tutoring
Replies: 3
Views: 79

Re: Tutoring

I do not know of any private tutors for this course, but I am sure there are many out there. Website like Wyzant are helpful for finding tutors for different subjects. However, I do know for a fact that the Step-Up and Workshops held by Dr. Lavelle's UAs are extremely helpful for learning the topics...
by Kishan Shah 2G
Thu Oct 10, 2019 4:26 pm
Forum: Balancing Chemical Reactions
Topic: compound state in chem rxn
Replies: 3
Views: 148

Re: compound state in chem rxn

Usually the problem with either state the state of the compound or element, but sometimes they may not for really simple equations. For example, if Oxygen is a product, it is usually in its diatomic gaseous form and it may not always be given to you.
by Kishan Shah 2G
Thu Oct 10, 2019 4:19 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: # of molecules and formula units?
Replies: 5
Views: 195

Re: # of molecules and formula units?

As Anjali noted, they indeed have different meanings, however for the sake of Unit 1 material, you can consider them the same since Avogadro's constant will be used to solve problems that ask either for formula units or number of molecules.
by Kishan Shah 2G
Wed Oct 09, 2019 2:00 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Ratio Rounding
Replies: 6
Views: 95

Re: Empirical Ratio Rounding

Usually you will intuitively know if the number is able to be rounded to a whole number or not. Usually my values that I round accurately to a whole number are within .05 of the whole number. If they are not whole numbers, in which it can happen, write the empirical formula down with the decimal sub...
by Kishan Shah 2G
Tue Oct 08, 2019 7:26 pm
Forum: Administrative Questions and Class Announcements
Topic: Finding Textbook Questions on the Quantum World
Replies: 4
Views: 61

Re: Finding Textbook Questions on the Quantum World

To answer your first question. The quantum questions for 1A begin on page 9 and are at the end of the reading for section A. As for turning in fundamentals problems vs quantum problems for hw this week, Dr. Lavelle's email this week said fundamentals questions "and/or" quantum questions. S...
by Kishan Shah 2G
Tue Oct 01, 2019 6:27 pm
Forum: SI Units, Unit Conversions
Topic: Units
Replies: 5
Views: 107

Units

Hello all. This may be a question that you won't be able to answer definitively, however I thought it was worth a try to ask anyways. Does anybody know to what extent we have to know prefixes for the various types of units and how to convert from them back to standard units(eg: microgram to gram, na...
by Kishan Shah 2G
Mon Sep 30, 2019 10:27 pm
Forum: Molarity, Solutions, Dilutions
Topic: G.17 Homework Problem
Replies: 3
Views: 57

Re: G.17 Homework Problem

It is the same calculation as part A, except you need to use the molar mass for CuSO4 x 5H2O in this part. This molar mass is 249.68 grams/mol.
by Kishan Shah 2G
Mon Sep 30, 2019 10:26 pm
Forum: Limiting Reactant Calculations
Topic: Using mols or grams
Replies: 4
Views: 89

Re: Using mols or grams

Yes. I don't see a problem using this method. I think Dr. Lavelle stated to use mols because it is easier to see visually, but you could do grams as well. The answer would be the same.
by Kishan Shah 2G
Mon Sep 30, 2019 10:21 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Avogadro's Number
Replies: 4
Views: 92

Re: Avogadro's Number

I personally use 6.022 x 10^23 and my answers are correct when I use this value. In addition, because Dr. Lavelle uses this value, I recommend going with it.
by Kishan Shah 2G
Mon Sep 30, 2019 10:15 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Formula Units
Replies: 4
Views: 74

Re: Formula Units

I can give you a definitive answer to the first part of your question. Yes, formula units do mean the same thing as atoms. As for the second question, I would assume that formula units do not change for dissolved ionic compounds due to the fact that atoms are neither being created nor destroyed duri...
by Kishan Shah 2G
Mon Sep 30, 2019 10:11 pm
Forum: Empirical & Molecular Formulas
Topic: Percent Mass Composition
Replies: 7
Views: 194

Re: Percent Mass Composition

Adding on, if the total mass of the compound is given and the respective masses of each element are given like the example regarding Vitamin C in class, then you need to divide each respective mass by the total mass given and then find the percent mass composition. From this point on you can continu...
by Kishan Shah 2G
Sun Sep 29, 2019 10:57 pm
Forum: Molarity, Solutions, Dilutions
Topic: Homework Problem G.11
Replies: 2
Views: 30

Re: Homework Problem G.11

Personally, I would simply convert 4.50 mmol glucose to mol which translates into .0450 mol of glucose. Then I would multiply this value by the reciprocal of the molarity of glucose given (M= 0.278).
by Kishan Shah 2G
Sun Sep 29, 2019 10:48 pm
Forum: Molarity, Solutions, Dilutions
Topic: Homework Question G.5
Replies: 4
Views: 123

Re: Homework Question G.5

Hi, you would begin to solve the problem by converting 50 mg of sodium carbonate to grams of sodium carbonate. Then, you would need to convert this mass of sodium carbonate to moles of sodium carbonate by dividing by the molar mass of the compound. Finally, you would need to take this value and mult...

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