Search found 44 matches

by Leela_Mohan3L
Sat Dec 08, 2018 6:12 pm
Forum: Identifying Acidic & Basic Salts
Topic: salts of weak acids and bases
Replies: 4
Views: 174

Re: salts of weak acids and bases

A salt of a weak acid contains a strong conjugate base as its anion. This strong conjugate base is good at pulling a proton off H2O and thus OH- ions will be produced, making the solution basic. A salt of a weak base contains a strong conjugate acid, which is good at giving protons to H2O. This will...
by Leela_Mohan3L
Sat Dec 08, 2018 10:39 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands
Replies: 2
Views: 47

Re: Ligands

Ligands are lewis bases that donate an electron pair to a transition metal cation (lewis acid) and form a coordinate covalent bond with it. Multiple ligands can bond to the same transition metal cation, which forms a coordination complex. In terms of which ligands you need to know about, refer to &q...
by Leela_Mohan3L
Wed Dec 05, 2018 10:28 pm
Forum: Calculating the pH of Salt Solutions
Topic: The pH of Solutions of Weak Acids and Bases 12.65
Replies: 5
Views: 107

Re: The pH of Solutions of Weak Acids and Bases 12.65

I think its because the bromide ion is the anion of a strong acid, not a weak acid. Thus, it is ineffective at pulling a proton off water. This leaves the solution as neutral? In general, strong acids have weak conjugate bases.

I'm not completely sure though so someone correct me if I'm wrong.
by Leela_Mohan3L
Wed Dec 05, 2018 3:43 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 4918

Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]

Thank you! Does the compound in number 31 have a net charge? [Ni (NH3)5 NO2]^+2 Because the Nickel has a 3+ charge and the NO2 has a 1- charge, it brings it to a net charge of 2+. NH3 has no charge. I hope this helps. Please correct me if I made a mistake. Thanks That's what I was thinking as well....
by Leela_Mohan3L
Wed Dec 05, 2018 2:38 pm
Forum: Administrative Questions and Class Announcements
Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Replies: 118
Views: 4918

Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]

Thank you! Does the compound in number 31 have a net charge?
by Leela_Mohan3L
Tue Dec 04, 2018 1:18 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Why is HCOOH a stronger acid than CH3COOH? [ENDORSED]
Replies: 2
Views: 113

Why is HCOOH a stronger acid than CH3COOH? [ENDORSED]

I read something about the CH3 functional group having "electron donating properties," which destabilizes the conjugate base anion, but I don't really understand how that works.
by Leela_Mohan3L
Sun Dec 02, 2018 2:59 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: How to determine shape of coordination compound
Replies: 3
Views: 87

How to determine shape of coordination compound

Specifically, how do you determine whether the shape is tetrahedral or square planar. How do you know how many lone pairs are on the transition metal cation in the center?
by Leela_Mohan3L
Sun Dec 02, 2018 2:54 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: How to tell whether a compound is polydentate
Replies: 2
Views: 31

Re: How to tell whether a compound is polydentate

The shape of the ligand (or rather, where each atom is placed) does affect whether a molecule is mono/bi/tridentate! For example, if you had a ring-shaped ligand that had a binding site on one end and another binding site on the complete opposite end, then the molecule is monodentate (This is becau...
by Leela_Mohan3L
Sun Dec 02, 2018 2:10 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: How to tell whether a compound is polydentate
Replies: 2
Views: 31

How to tell whether a compound is polydentate

I know that it has to do with the amount of ligands with lone pairs, but does the shape of the ligand matter as well when determining whether it is bidentate or tridentate?
by Leela_Mohan3L
Sat Dec 01, 2018 5:06 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Question 12.19 (6th Edition)
Replies: 1
Views: 35

Question 12.19 (6th Edition)

The concentration of HCl is reduced to 12% of its initial value by dilution. By what amount does the pH of the solution change.
by Leela_Mohan3L
Thu Nov 29, 2018 11:36 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining Dipoles
Replies: 2
Views: 60

Re: Determining Dipoles

The dipole direction goes towards the more electronegative atom. For example, if you have HF, the dipole would be pointing towards fluorine since it is more electronegative than Hydrogen. Thus, the Hydrogen would be delta positive and the Fluorine would be delta negative.
by Leela_Mohan3L
Sun Nov 18, 2018 11:29 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shape vs. Electron Geometry [ENDORSED]
Replies: 2
Views: 41

Re: Molecular shape vs. Electron Geometry [ENDORSED]

Molecular shape takes into account the atoms that are bonded to the central atom, whereas electron geometry takes into account the atoms bonded to the central atom as well as lone pairs around the central atom. Let's use the lewis structure of H2O as an example. The molecular geometry for an H2O mol...
by Leela_Mohan3L
Tue Nov 13, 2018 11:37 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: phases caused by interactions
Replies: 3
Views: 103

Re: phases caused by interactions

The intermolecular forces between molecules are what determine the state of something. Generally, the stronger the intermolecular forces, the more likely something will be a solid at room temperature or have a higher boiling point.
by Leela_Mohan3L
Tue Nov 13, 2018 11:26 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Hybridization of Central Atom
Replies: 1
Views: 45

Re: Hybridization of Central Atom

We will be going into that probably some time next week.
by Leela_Mohan3L
Wed Nov 07, 2018 3:06 pm
Forum: Dipole Moments
Topic: Dispersion strengths of larger atoms
Replies: 5
Views: 90

Re: Dispersion strengths of larger atoms

Why do more electrons make an atom/molecule more polarizable though? I get how the size of the atom relates to polarizability but not how the amount of electrons are related to it.
by Leela_Mohan3L
Sat Nov 03, 2018 10:13 am
Forum: Empirical & Molecular Formulas
Topic: Mass Composition
Replies: 3
Views: 127

Re: Mass Composition

If the mass composition doesn't add up to 100% then that is an indication that there is another element present in the compound. Depending on the problem, you would be able to tell which element is missing. Ex: if the problem was asking you to find the molecular formula of a compound that was burned...
by Leela_Mohan3L
Thu Nov 01, 2018 9:43 pm
Forum: Electronegativity
Topic: Trends in EN and IE
Replies: 1
Views: 37

Re: Trends in EN and IE

Ionization energy increases from left to right because the amount of protons is increasing, and thus the nuclear charge increases. As a result, the electrons are more attracted to the nucleus, which makes them more difficult to remove. Electronegativity increases from left to right for the same reas...
by Leela_Mohan3L
Thu Nov 01, 2018 9:18 pm
Forum: Lewis Structures
Topic: Lewis Structure of Glycine
Replies: 1
Views: 23

Lewis Structure of Glycine

Would we be expected to know how to draw complex lewis structures (like Glycine H2C(NH2)COOH) on the midterm?
by Leela_Mohan3L
Thu Nov 01, 2018 9:18 pm
Forum: Lewis Structures
Topic: Lewis Structure of Glycine
Replies: 1
Views: 43

Lewis Structure of Glycine

Would we be expected to know how to draw complex lewis structures (like Glycine H2C(NH2)COOH) on the midterm?
by Leela_Mohan3L
Thu Nov 01, 2018 9:16 pm
Forum: Resonance Structures
Topic: 2C.5 (7th ed)
Replies: 3
Views: 73

Re: 2C.5 (7th ed)

O has an even amount of valence electrons (6) while Cl has an odd amount of valence electrons (7). Thus, Cl is the radical since it has an odd amount of valence electrons.
by Leela_Mohan3L
Thu Nov 01, 2018 7:48 pm
Forum: Resonance Structures
Topic: 2C.5 (7th ed)
Replies: 3
Views: 73

Re: 2C.5 (7th ed)

O has an even amount of valence electrons (6) while Cl has an odd amount of valence electrons (7). Thus, Cl is the radical since it has an odd amount of valence electrons.
by Leela_Mohan3L
Thu Nov 01, 2018 7:33 pm
Forum: Octet Exceptions
Topic: Valence Electrons
Replies: 1
Views: 55

Re: Valence Electrons

An atom will lose electrons from the subshell with a higher energy. Thus, if an atom has electrons in the 3d and 4s shells, it will lose electrons from the 4s subshell when being ionized because the 4s subshell has a higher energy.
by Leela_Mohan3L
Sat Oct 27, 2018 5:25 pm
Forum: Trends in The Periodic Table
Topic: 7th edition 1F.3
Replies: 2
Views: 76

Re: 7th edition 1F.3

All of these atoms have the same amount of electrons, so you can look at the number of protons as an indicator of atomic radius. When going across a period, more protons --> smaller atomic radius. This is because the amount of protons increases the nuclear charge which increases the attraction of th...
by Leela_Mohan3L
Sat Oct 27, 2018 5:18 pm
Forum: Trends in The Periodic Table
Topic: Homework 2.67b
Replies: 2
Views: 65

Re: Homework 2.67b

This is because carbon has an empty 2p orbital that can be filled with an electron. A half filled 2p subshell is more stable than a partially filled 2p subshell. Nitrogen, on the other hand, does not have an empty orbital to accomodate an electron and thus has a lower affinity for electrons.
by Leela_Mohan3L
Wed Oct 17, 2018 6:29 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Conflict with lecture and solution manual
Replies: 1
Views: 40

Re: Conflict with lecture and solution manual

On his website there is a document titled "Solution Manual Errors" and that question is listed in there. So when doing problems like this you would use the method that Dr. Lavelle taught us!
by Leela_Mohan3L
Tue Oct 16, 2018 10:41 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Question 1.15 sixth edition
Replies: 10
Views: 154

Re: Question 1.15 sixth edition

The Lyman series refers to the wavelengths of light that are absorbed by hydrogen in the Ultraviolet spectrum . The principal quantum number for this series is n=1, meaning that whenever one of the specific wavelengths in this series is absorbed by hydrogen, an electron will jump from the n=1 energy...
by Leela_Mohan3L
Tue Oct 16, 2018 10:31 pm
Forum: Ionic & Covalent Bonds
Topic: Electron Configuration of Cations
Replies: 8
Views: 174

Re: Electron Configuration of Cations

Copper (I) has a +1 charge, so in order to get this charge you have to remove one electron. Copper (II) has a +2 charge, so you have to remove two electrons.
by Leela_Mohan3L
Tue Oct 16, 2018 10:29 pm
Forum: Properties of Electrons
Topic: Example 1B.3
Replies: 2
Views: 59

Re: Example 1B.3

The mass of an electron is provided on the formula sheet that's on Dr. Lavelle's website, and it will be given to us on the test!
by Leela_Mohan3L
Tue Oct 16, 2018 10:25 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Indeterminacy vs. Uncertainty?
Replies: 4
Views: 116

Re: Indeterminacy vs. Uncertainty?

I think he said something about how the word "uncertainty" makes it seem like we don't know anything about the particle's momentum or position, when in reality we can approximate it.
by Leela_Mohan3L
Mon Oct 15, 2018 9:31 pm
Forum: Einstein Equation
Topic: Question regarding wavelength
Replies: 5
Views: 90

Question regarding wavelength

When would you use λ = c/v to find wavelength and when would you use λ = hc/E to find wavelength? Are they both referring to the wavelength of a photon?
by Leela_Mohan3L
Thu Oct 11, 2018 11:24 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: En= -hR/n^2
Replies: 3
Views: 79

Re: En= -hR/n^2

There is a way to modify this equation to make it work for one electron ions, however I believe we will only have to know the equation for Hydrogen atoms.
by Leela_Mohan3L
Wed Oct 10, 2018 4:08 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Threshold Energy
Replies: 4
Views: 51

Re: Threshold Energy

Threshold energy is the amount of energy required to remove an electron from an atom of a certain material. The electron will only be removed if the light source has enough energy to overcome this threshold energy.

Hope that helps!
by Leela_Mohan3L
Mon Oct 08, 2018 8:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Periodic Table
Replies: 6
Views: 109

Re: Periodic Table

Yes they will be, according to past students.
by Leela_Mohan3L
Mon Oct 08, 2018 8:53 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect
Replies: 2
Views: 53

Re: Photoelectric Effect

Hi Adrienne. According to the photoelectric effect, light is made up of photons. When you have light with a long wavelength, the photons in that light do not have sufficient energy to remove an electron from an atom of a metal. When you increase the amplitude of this light wave (aka the intensity of...
by Leela_Mohan3L
Mon Oct 08, 2018 8:40 pm
Forum: Empirical & Molecular Formulas
Topic: M19
Replies: 3
Views: 157

Re: M19

In this problem, you can determine the molecular formula of caffeine by finding the grams of Carbon, Hydrogen, and Nitrogen that are present. Once you add these masses up, you'll see that they do not equal the total mass of the initial hydrogen compound and therefore there has to be another element ...
by Leela_Mohan3L
Fri Oct 05, 2018 1:13 pm
Forum: Properties of Light
Topic: Behavior of small objects - clarification
Replies: 3
Views: 61

Re: Behavior of small objects - clarification

If you have water being poured from a bucket with a large opening into a cup that sits on top of a scale, the reading on the scale will gradually increase as the amount of water in the cup increases. However, if you decrease the opening of that bucket so much so that only one molecule of H20 can com...
by Leela_Mohan3L
Thu Oct 04, 2018 12:05 am
Forum: Molarity, Solutions, Dilutions
Topic: Question G25 (6th Edition)
Replies: 1
Views: 103

Question G25 (6th Edition)

Question: Practitioners of the branch of alternative medicine known as homeopathy claim that very dilute solutions of substances can have an effect. Is the claim plausible? To explore this question, suppose that you prepare a solution of a supposedly active substance, X, with a molarity of 0.10 mol/...
by Leela_Mohan3L
Tue Oct 02, 2018 2:54 pm
Forum: Empirical & Molecular Formulas
Topic: Question M19 (6th edition)
Replies: 3
Views: 287

Re: Question M19 (6th edition)

This makes a lot of sense, thank you! So in general, if we aren't sure what elements are included in an unknown compound, we should calculate the masses of each individual element and then add them up in order to verify that they equal the mass of the initial unknown compound? I hope my question mak...
by Leela_Mohan3L
Mon Oct 01, 2018 11:03 pm
Forum: Empirical & Molecular Formulas
Topic: Question M19 (6th edition)
Replies: 3
Views: 287

Question M19 (6th edition)

Question: A stimulant in coffee and tea is caffeine, a substance of molar mass 194 g mol 1. When 0.376 g of caffeine was burned, 0.682 g of carbon dioxide, 0.174 g of water, and 0.110 g of nitrogen were formed. Determine the empirical and molecular formulas of caffeine, and write the equation for it...
by Leela_Mohan3L
Mon Oct 01, 2018 6:43 pm
Forum: SI Units, Unit Conversions
Topic: Naming Compounds
Replies: 8
Views: 222

Re: Naming Compounds

Calcium sulfide is an ionic compound. You know this because it consists of a cation (calcium) and an anion (sulfide). Calcium as a 2+ charge and sulfide has a 2- charge. An ionic compound must have a net charge of 0, therefore you get CaS.
by Leela_Mohan3L
Sat Sep 29, 2018 9:59 pm
Forum: Balancing Chemical Reactions
Topic: Question H21 (6th Edition)
Replies: 2
Views: 105

Question H21 (6th Edition)

Question: The psychoactive drug methamphetamine which is sold as the prescription medication Desoxyn C10H15N, undergoes a series of reactions in the body; the net result of these reactions is the oxidation of solid methamphetamine by oxygen gas to produce carbon dioxide gas, liquid water, and an aqu...
by Leela_Mohan3L
Sat Sep 29, 2018 9:43 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Question E1(6th Edition)
Replies: 7
Views: 197

Re: Question E1(6th Edition)

I began this problem by multiplying 1.00 mol of Ag by Avogadro's number to get 6.022x10^23 atoms of Ag. Then I multiplied that by 2(144 pm)--144 pm is the radius of the atom, so to get the total length of the atom you have to double it. The end result was 1.73x10^26 pm, which is equal to 1.73x10^11 ...

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