Search found 35 matches

by OrAmar-1L
Mon Jun 04, 2018 8:54 pm
Forum: Lewis Structures
Topic: Levels of electron density
Replies: 1
Views: 100

Levels of electron density

I hear the phrase "levels of electron density" in discussion and lecture and I still don't really know what it means or why it matters. Could someone explain please? Thanks!
by OrAmar-1L
Mon Jun 04, 2018 8:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam [ENDORSED]
Replies: 5
Views: 239

Final Exam [ENDORSED]

Does anybody know what the breakdown of the final exam will be? I know it'll be 8 questions, but are there any topics that are/aren't more likely to be on it, or some chapters that will be more heavily asked? Thanks!
by OrAmar-1L
Mon Jun 04, 2018 8:49 pm
Forum: Resonance Structures
Topic: Radicals
Replies: 13
Views: 432

Re: Radicals

Does an atom in the molecule being a radical have anything to do with the formal charge? Im looking for ways to tell that there will be a radical.
by OrAmar-1L
Mon Jun 04, 2018 8:45 pm
Forum: Lewis Structures
Topic: Expanded octets
Replies: 6
Views: 158

Expanded octets

Which elements can expand their octets, why can they do this, and how many electrons can they take?
by OrAmar-1L
Mon Jun 04, 2018 8:45 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charge
Replies: 5
Views: 145

Formal charge

In regards to counting the electrons on the molecule to make sure that each atom has the right amount, when are bonds counted as two electrons and when are they counted as one? I might be pretty confused so if the question is off let me know(:
by OrAmar-1L
Mon Jun 04, 2018 8:43 pm
Forum: Biological Examples
Topic: Hemoglobin Structure
Replies: 3
Views: 153

Re: Hemoglobin Structure

Almost sure that he said that we don't need to know that "for the scope of this class".
by OrAmar-1L
Mon Jun 04, 2018 8:41 pm
Forum: Bronsted Acids & Bases
Topic: How to identify a Bronsted acid or base
Replies: 11
Views: 370

Atoms that donate protons are acids, and atoms that accept protons are bases. Hope this helps!
by OrAmar-1L
Mon Jun 04, 2018 8:40 pm
Forum: Lewis Acids & Bases
Topic: Given PH first
Replies: 4
Views: 258

Re: Given PH first

The formula given in class was pH = -log[H3O+]
by OrAmar-1L
Mon Jun 04, 2018 8:37 pm
Forum: Lewis Acids & Bases
Topic: Strength between 2 weak/strong acids/bases
Replies: 5
Views: 204

Re: Strength between 2 weak/strong acids/bases

The stronger an acid is, the more easily it loses a proton
by OrAmar-1L
Mon Jun 04, 2018 8:36 pm
Forum: Lewis Acids & Bases
Topic: acids/bases electrons
Replies: 2
Views: 61

Re: acids/bases electrons

Acids are protons donors and electron acceptors, bases are electron donors and proton acceptors.
by OrAmar-1L
Mon Jun 04, 2018 8:30 pm
Forum: Sigma & Pi Bonds
Topic: Pi bonds
Replies: 3
Views: 250

Re: Pi bonds

Pi bonds come from the double and triple bonds formed by overlapping orbitals when atoms share electrons (covalent bonding). So yes, you're right(:
by OrAmar-1L
Mon Jun 04, 2018 8:29 pm
Forum: Sigma & Pi Bonds
Topic: delocalized pi bond
Replies: 5
Views: 742

Re: delocalized pi bond

so what's the difference between delocalized pi bonds and resonance structure?
by OrAmar-1L
Mon Jun 04, 2018 8:27 pm
Forum: Sigma & Pi Bonds
Topic: Difference between Bonds [ENDORSED]
Replies: 7
Views: 404

Re: Difference between Bonds [ENDORSED]

Taizha 1C wrote:What is an example of how we may be given a test question for sigma and pi bonds?


He'll probably give us a molecule and tell us to draw the lewis structure and label the sigma and pi bonds.
by OrAmar-1L
Wed May 30, 2018 3:44 pm
Forum: Lewis Structures
Topic: Central Atom(s)
Replies: 6
Views: 141

Central Atom(s)

How would I know what the central atom or atoms should be in my Lewis structure for a compound?
by OrAmar-1L
Wed May 30, 2018 3:37 pm
Forum: Lewis Structures
Topic: Lewis Structures with Transition Metals
Replies: 2
Views: 122

Re: Lewis Structures with Transition Metals

I believe the most stable structure would have been the one which made the charge of the entire molecule 0. So, for example, the transition metal was bonded to Nitrogen, then it would need a charge of +3. Hope this helps!
by OrAmar-1L
Wed May 30, 2018 3:33 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Px, Py, and Pz
Replies: 2
Views: 72

Px, Py, and Pz

I don't really understand the concept of the P orbitals and how the professor keeps relating them to "electron depth". If someone could help me out it would be much appreciated!
by OrAmar-1L
Fri May 18, 2018 4:28 pm
Forum: Lewis Structures
Topic: Charge on Molecule [ENDORSED]
Replies: 4
Views: 114

Charge on Molecule [ENDORSED]

Is there any way to know which atom in a molecule will carry the negative or positive charge shown outside the brackets on the whole molecule? Thanks!
by OrAmar-1L
Fri May 18, 2018 4:27 pm
Forum: Ionic & Covalent Bonds
Topic: Lewis Acids and Bases
Replies: 4
Views: 110

Re: Lewis Acids and Bases

The charge of the molecule/ atoms in it can effect the acidity, but not so much the bond itself. However, ionic bonds are made up of charged particles, but they are opposites and usually cancel each other out. Hope this helps!
by OrAmar-1L
Fri May 18, 2018 4:24 pm
Forum: Lewis Structures
Topic: Question about Test 3 Material [ENDORSED]
Replies: 2
Views: 100

Re: Question about Test 3 Material [ENDORSED]

Lewis Structures will be on the test but electron configurations won't, they were on Test 2. Hope this helps!
by OrAmar-1L
Fri May 11, 2018 12:54 am
Forum: Quantum Numbers and The H-Atom
Topic: Midterm Question
Replies: 13
Views: 355

Re: Midterm Question

Each group has a certain amount of orbitals. Since the s block only has 2 elements, it can only hold 2 electrons, and thus one orbital. The p block has 6 elements, so 6 electrons in 3 orbitals. D block has 10 elements, so 10 electrons in 5 orbitals. And the F block has 14 elements, so 14 electrons i...
by OrAmar-1L
Fri May 11, 2018 12:52 am
Forum: Trends in The Periodic Table
Topic: Octets and ionization energy
Replies: 2
Views: 138

Re: Octets and ionization energy

Oxygen's lower ionization energy exception to the trend is because of its Lewis structure, as Lavelle said in class. We haven't learned much about that yet so I don't think you need to worry about it until the coming lectures
by OrAmar-1L
Fri May 11, 2018 12:49 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Px, Py, Pz orbitals
Replies: 2
Views: 247

Px, Py, Pz orbitals

Can someone explain to me the concept of the Px, Py, and Pz orbitals? I don't really understand how it applies to the 4 quantum numbers we already have. Thank you!
by OrAmar-1L
Tue May 01, 2018 1:35 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 3d and 4s orbitals
Replies: 3
Views: 113

Re: 3d and 4s orbitals

The 3d orbital has n=3, and the 4s orbital has n=4. The principal quantum number (n) determines the energy and size, so the one with the higher n value will have more energy.
by OrAmar-1L
Tue May 01, 2018 1:31 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Probability Definition
Replies: 2
Views: 65

Re: Probability Definition

The quote says "lies between" so yes, it can be between 0 and 1. Does not have to be one or the other(:
by OrAmar-1L
Tue May 01, 2018 1:29 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals in Relation to Periodic Table
Replies: 2
Views: 73

Re: Orbitals in Relation to Periodic Table

How exactly do the orbitals correlate to the blocks on the periodic table? I know that there is an s-, p-, d-, and f- block on the periodic table, as well as the s-, p-, d-, f- orbitals, but I just can't seem to see how both are related to eachother. Since the first row of the S block has 2 element...
by OrAmar-1L
Thu Apr 26, 2018 12:48 pm
Forum: Properties of Electrons
Topic: Spin Magnetic Quantum Number
Replies: 2
Views: 118

Spin Magnetic Quantum Number

Can someone explain to me the concept of the fourth quantum number we learned in Wednesday's lecture? The whole spin-up and spin-down thing didn't really make sense to me. Thank you!
by OrAmar-1L
Thu Apr 26, 2018 12:44 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Constant [ENDORSED]
Replies: 6
Views: 188

Re: Rydberg Constant [ENDORSED]

I'd recommend doing the homework and studying with the equation sheet on his website. Better to use the resources he's gonna give us on the test(: and yes, on that it says Rydberg's constant is 3.289x10^15. Hope this helps!
by OrAmar-1L
Thu Apr 26, 2018 12:41 pm
Forum: Properties of Light
Topic: HW Q
Replies: 3
Views: 154

Re: HW Q

I believe you would need more information, because the equation will leave you with two unknown variables (n1 and n2). With the given wavelength, you can calculate for frequency, but you would still need to know the initial or final energy level to solve for the other. The word "emission" ...
by OrAmar-1L
Fri Apr 06, 2018 12:53 pm
Forum: Administrative Questions and Class Announcements
Topic: Modules
Replies: 5
Views: 159

Re: Modules

The modules aren't being calculated into our final grade but they are really good practice for the quizzes. Have a good weekend.
by OrAmar-1L
Fri Apr 06, 2018 12:52 pm
Forum: Empirical & Molecular Formulas
Topic: Determining Molecular Formula Based on Name of Molecule [ENDORSED]
Replies: 5
Views: 169

Re: Determining Molecular Formula Based on Name of Molecule [ENDORSED]

I think we won't have to name the extremely complex molecules. Simple ones where you only have to add up the charges so that they are equal to zero like your question are fair game. Have a good weekend
by OrAmar-1L
Fri Apr 06, 2018 12:48 pm
Forum: Significant Figures
Topic: E29 Textbook Answer [ENDORSED]
Replies: 1
Views: 105

Re: E29 Textbook Answer [ENDORSED]

We are provided a periodic table of elements for each exam. Use the atomic mass given on that table and you will get full points. :)
by OrAmar-1L
Thu Oct 05, 2017 10:36 pm
Forum: Empirical & Molecular Formulas
Topic: Question M19 (Molecular Formula)
Replies: 5
Views: 292

Re: Question M19 (Molecular Formula)

What also helps to remember is that typically for combustion reactions, for every 1 mole of CO2 produced, 1 mole of C was in the initial compound; for every 1 mole of H2O produced, 2 moles of H were in the initial compound; and for every 1 mole of N2 produced, 2 moles of N were in the initial compo...
by OrAmar-1L
Thu Oct 05, 2017 10:34 pm
Forum: Empirical & Molecular Formulas
Topic: Question M19 (Molecular Formula)
Replies: 5
Views: 292

Re: Question M19 (Molecular Formula)

What I did is I found out how many grams of carbon (0.682g * (1 mol CO2/44.01g) * (1 mol C/1 mol CO2) * molar mass of carbon to get grams), hydrogen (same process as carbon), and nitrogen. Then I did 0.376-(mass carbon+mass hydrogen+mass nitrogen) to get the grams of oxygen, and then divided that b...
by OrAmar-1L
Thu Oct 05, 2017 10:32 pm
Forum: SI Units, Unit Conversions
Topic: Exercise F11
Replies: 4
Views: 239

Re: Exercise F11

If after dividing each number by the smallest value you have, you should have your ratio (roughly). In your case, I think it's pretty safe to assume 5.9 would be 6 in relative terms.. in fact, we are rounding to significant figures most of the time. On a test, I would just check all the options and ...
by OrAmar-1L
Thu Oct 05, 2017 5:00 pm
Forum: Empirical & Molecular Formulas
Topic: Question M19 (Molecular Formula)
Replies: 5
Views: 292

Question M19 (Molecular Formula)

For question M19, I'm very confused as to how to find the amount of grams of oxygen in the compound caffeine, because 2 of the products (CO2 and H20) both have oxygen! Please help

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