Search found 30 matches

by Luis Torres 1C
Sun Jun 10, 2018 6:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Helpful Chart
Replies: 18
Views: 515

Re: Helpful Chart

We made a similar chart in discussion too. I want to point out that I believe our TA mentioned something about the angles being less than 109.5 in some cases, I'm not exactly sure why or in what instances, but I think he mentioned lone pairs. I also think Lavelle said that we don't have to know the...
by Luis Torres 1C
Sun Jun 10, 2018 6:13 pm
Forum: Naming
Topic: Coordination number
Replies: 10
Views: 379

Re: Coordination number

As stated above, the coordination number indicates the number of atoms that surround the central atom. To add to that answer, these 'non-central' atoms are called ligands
by Luis Torres 1C
Thu Jun 07, 2018 8:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Shapes Practice [ENDORSED]
Replies: 1
Views: 90

VSEPR Shapes Practice [ENDORSED]

To anyone who thinks they need practice on naming the shape of VSEPR models, I have found this really cool online quiz that helps with reviewing

https://www.sporcle.com/games/sproutcm/ ... iprismatic
by Luis Torres 1C
Sat Jun 02, 2018 4:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Problem 4.27
Replies: 4
Views: 152

Re: Problem 4.27

Polar molecules have an unequal distribution of electrons, leading to partial positive and partial negative charges in different regions of the molecule. If you look at the Lewis Structure of C 2 H 6 , you'll notice that there is no unequal distribution of electrons, and all atoms have a full octet....
by Luis Torres 1C
Sat Jun 02, 2018 4:23 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Cisplatin [ENDORSED]
Replies: 1
Views: 128

Re: Cisplatin [ENDORSED]

It is true that NH 3 has a lone pair. However, that lone pair is what bonds to the Pt atom, so it is not available to be shared with the DNA. I've drawn this simplified molecule structure (which may be chemically incorrect, but is simply for a visual) to help. The NH 3 is unable to form any addition...
by Luis Torres 1C
Fri Jun 01, 2018 11:51 pm
Forum: Hybridization
Topic: Textbook 4.37
Replies: 3
Views: 136

Textbook 4.37

4.37 Identify the hybrid orbitals used by the phosphorus atom in each of the following species: (d) PCl 3 I have been using the following drawing method to identify hybrid orbitals, and it has been successful so far. However, when I get to part d, my answer is sp 3 d, but the correct answer is sp 3 ...
by Luis Torres 1C
Sun May 27, 2018 3:05 pm
Forum: Hybridization
Topic: Hybridization
Replies: 2
Views: 76

Re: Hybridization

I believe hybridization is used to explain how it is atoms get their specific bonding characteristics. For example, in class on Friday, Dr. Lavelle gave the example of Carbon which has a full s-orbital (2s 2 ) and 2 p-orbital electrons (2p 2 ). By this model, we would expect Carbon can only form 2 b...
by Luis Torres 1C
Sun May 27, 2018 2:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AXE Notation and Shape
Replies: 4
Views: 220

Re: AXE Notation and Shape

The number of single/double/triple bonds are not taken account in the AXE notation. All that is considered is the number of atoms bonded around the central atom (whether that be single, double, triple) denoted by X, and the number of lone pairs denoted by E.
by Luis Torres 1C
Sun May 27, 2018 2:29 pm
Forum: Bond Lengths & Energies
Topic: Bond Order
Replies: 4
Views: 241

Re: Bond Order

Alejandro Salazar 1D wrote:Bond order formula

BO: (1/2)(number of bonds-number of anti bonds)

What exactly is an anti bond?
by Luis Torres 1C
Sun May 20, 2018 11:07 pm
Forum: Lewis Structures
Topic: Lone pair electrons
Replies: 5
Views: 186

Re: Lone pair electrons

By convention, the electrons are just represented as dots. I would avoid using lines to represent lone pairs, as lines are typically used to represent bonds between atoms, just to avoid confusion
by Luis Torres 1C
Thu May 17, 2018 1:58 pm
Forum: Ionic & Covalent Bonds
Topic: How to tell which elements will be most likely to form a covalent bond
Replies: 8
Views: 249

Re: How to tell which elements will be most likely to form a covalent bond

The electronegativity difference would be used to determine if an ionic or covalent bond is formed. Just as stated above, a difference greater than 2 forms an ionic bond, and a difference less than 1.5 forms a covalent bond. A rough estimate could also be done by simply looking at the periodic table...
by Luis Torres 1C
Thu May 17, 2018 1:48 pm
Forum: Coordinate Covalent Bonds
Topic: Coordinate Covalent Bonds
Replies: 4
Views: 418

Coordinate Covalent Bonds

I know we've somewhat gone over this in class, but could someone explain what exactly is a coordinate covalent bond?
by Luis Torres 1C
Sun May 13, 2018 11:06 pm
Forum: Lewis Structures
Topic: resonance
Replies: 6
Views: 204

Re: resonance

When drawing Lewis Structures, it is possible to put bonds between various different atoms, and still yield a 'correct' structure. The concept of resonance accounts for all of these differences. The average of all of the possible resonance structures is what yields the 'true' lewis structure.
by Luis Torres 1C
Sun May 13, 2018 10:26 pm
Forum: Ionic & Covalent Bonds
Topic: 3.25 part c
Replies: 3
Views: 120

Re: 3.25 part c

Aluminum ions are typically +3. Therefore, it would take 3 Hydrogen atoms to match the one aluminum atom.
by Luis Torres 1C
Sun May 13, 2018 10:20 pm
Forum: Formal Charge and Oxidation Numbers
Topic: hw 3.53
Replies: 3
Views: 153

Re: hw 3.53

You would have to find the overall formal charge of each molecule, and then determine which one has a charge closest to zero. The charge closest to zero is the most stable (and thus, has the least energy)
by Luis Torres 1C
Sun May 06, 2018 11:41 pm
Forum: Quantum Numbers and The H-Atom
Topic: "ms" Quantum Number [ENDORSED]
Replies: 2
Views: 190

Re: "ms" Quantum Number [ENDORSED]

From questions I have seen, one important use of this concept is when a question asks "how many electrons are possible given the following quantum numbers?". An example of this is on another question that I think could help demonstrate how these questions are asked. https://lavelle.chem.uc...
by Luis Torres 1C
Sun May 06, 2018 9:28 pm
Forum: Empirical & Molecular Formulas
Topic: Test 1/ Question 8 [ENDORSED]
Replies: 6
Views: 383

Re: Test 1/ Question 8 [ENDORSED]

I would solve this first by finding the molecular formula. Since the molecular formula is the actual number of elements in the molecule, you would simply count how many of each atom there are. For example, the second molecule has 2 hydrogen atoms and 2 oxygen atoms. So the molecular formula is H 2 O...
by Luis Torres 1C
Sun May 06, 2018 9:17 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron configuration for P^3- [ENDORSED]
Replies: 2
Views: 114

Re: Electron configuration for P^3- [ENDORSED]

You would simply add three electrons to the next available orbitals. Adding the three electrons gives the atom an overall 3- charge.
by Luis Torres 1C
Fri Apr 27, 2018 7:41 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Coefficients in electron configurations [ENDORSED]
Replies: 4
Views: 229

Coefficients in electron configurations [ENDORSED]

From lecture today:

Calcium has an electron configuration of [Ar] 4s2

I'm unsure of why there would be a 4 involved. Could someone explain this please, thanks!
by Luis Torres 1C
Fri Apr 27, 2018 7:36 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Cutoff for wavelike properties [ENDORSED]
Replies: 2
Views: 87

Re: Cutoff for wavelike properties [ENDORSED]

Professor Lavelle had said in lecture that anything 10^-18 would be "pushing it". I think 10^-15, as Annie had said, would be a good cut-off.
by Luis Torres 1C
Fri Apr 27, 2018 7:22 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How detailed should the configurations be?
Replies: 3
Views: 121

Re: How detailed should the configurations be?

I believe that the short hand is usually acceptable, as it saves you time from having to write out the entire configuration. As for the p sub-levels, I think professor Lavelle had said that it isn't required to notify x,y,z specifically, but you can if you would like.
by Luis Torres 1C
Sun Apr 22, 2018 11:14 pm
Forum: Einstein Equation
Topic: Joules unit conversion [ENDORSED]
Replies: 2
Views: 119

Re: Joules unit conversion [ENDORSED]

1 J= 1 kg m^2 s^-2
by Luis Torres 1C
Sun Apr 22, 2018 11:03 pm
Forum: DeBroglie Equation
Topic: How do you calculate speed using the De Broglie equation? [ENDORSED]
Replies: 6
Views: 227

Re: How do you calculate speed using the De Broglie equation? [ENDORSED]

Manipulating the DeBroglie wavelength equation can help with solving for velocity



by Luis Torres 1C
Fri Apr 20, 2018 4:28 pm
Forum: Properties of Light
Topic: Test 2 [ENDORSED]
Replies: 4
Views: 209

Re: Test 2 [ENDORSED]

If you recall from test 1, we were given a cover sheet of constants and equations. I know that same cover sheet is being provided for test 2 and test 3, but I am not positive about the midterm/final. As for the units, as long as the question does not specify, you are free to use whichever. nm are us...
by Luis Torres 1C
Sun Apr 15, 2018 10:15 pm
Forum: SI Units, Unit Conversions
Topic: moles to atoms [ENDORSED]
Replies: 3
Views: 249

Re: moles to atoms [ENDORSED]

When going from moles to atoms, you would multiply by Avogadro's number. Since Avogadro's number is 6.02x10^23 atoms per mole, then multiplying this by an amount already in moles would cause the moles to cancel, and you are only left with the number of atoms. Think of it as a ratio, and consider wha...
by Luis Torres 1C
Sun Apr 15, 2018 10:10 pm
Forum: SI Units, Unit Conversions
Topic: Avogadro's Number [ENDORSED]
Replies: 11
Views: 423

Re: Avogadro's Number [ENDORSED]

It can be used both ways, as long as it is applied correctly (multiplying by it when going from moles to atoms and dividing when going from atoms to moles)
by Luis Torres 1C
Sun Apr 15, 2018 9:55 pm
Forum: Balancing Chemical Reactions
Topic: Balancing the Equation
Replies: 9
Views: 409

Re: Balancing the Equation

Though there isn't really a 'uniform' method, it always helps to start with an element that only appears in only one reactant and only one product. Balance that element first, and start moving to elements that appear multiple times. Some elements like Oxygen can appear multiple times, so it could be...
by Luis Torres 1C
Sun Apr 15, 2018 9:37 pm
Forum: Empirical & Molecular Formulas
Topic: Rounding atomic weight (general question) [ENDORSED]
Replies: 8
Views: 380

Re: Rounding atomic weight (general question) [ENDORSED]

Personally, I would use whatever is given in the question or periodic table and not round until the very end, just to make my calculations as accurate as possible
by Luis Torres 1C
Sun Apr 15, 2018 9:15 pm
Forum: Balancing Chemical Reactions
Topic: H.5: Balancing Equations
Replies: 6
Views: 396

Re: H.5: Balancing Equations

Although it may take up some space (and time), I prefer to re-write the entire equation each time I find a new coefficient as well as writing a small note next to it to keep track. Then to check my work, I write counts underneath the equation. For example NaBH4(s)+H2O(l)-->NaBO2(aq)+H2(g) NaBH4(s)+ ...
by Luis Torres 1C
Sun Apr 15, 2018 8:46 pm
Forum: Empirical & Molecular Formulas
Topic: Similar Formulas [ENDORSED]
Replies: 3
Views: 213

Similar Formulas [ENDORSED]

This question may be obvious, but I just wanted to make sure I didn't over think it. A deoxyribose is composed of 5 Carbon atoms, 10 Hydrogen atoms, and 4 Oxygen atoms. This would make its molecular formula C5H10O4. Would this same formula also be its empirical formula, since it cannot be reduced at...

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