Search found 33 matches

by Dennisse Diaz 1D
Wed Jun 13, 2018 11:47 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: strong acids
Replies: 4
Views: 292

Re: strong acids

Strong acids will release all of their hydrogens in water, therefore they will dissolve.
by Dennisse Diaz 1D
Wed Jun 13, 2018 3:08 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Happy Lavelle [ENDORSED]
Replies: 5
Views: 581

Happy Lavelle [ENDORSED]

Lavelle is always so happy to teach :,)
by Dennisse Diaz 1D
Mon Jun 11, 2018 8:59 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acids and bases
Replies: 3
Views: 200

Re: Acids and bases

Bond strength & Bond polarity: -the smaller the atom the stronger the bond strength -When going down a row in the Periodic Table, the atoms get larger so the strength of the bonds get weaker, which means the acids get stronger. Is this true for every row in the periodic table? Also, this was re...
by Dennisse Diaz 1D
Mon Jun 11, 2018 8:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angle [ENDORSED]
Replies: 4
Views: 213

Re: Bond Angle [ENDORSED]

In the notes he gave us the number of degrees for each type of angle/vsepr model. You should review the notes and try to memorize them!!
by Dennisse Diaz 1D
Mon Jun 11, 2018 8:53 pm
Forum: Sigma & Pi Bonds
Topic: strength of bonds
Replies: 3
Views: 170

Re: strength of bonds

A sigma bond remains unchanged upon rotation and so can rotate freely, but to rotate a pi bond you must break the chemical bond, rotate and reform. Bond breaking requires energy, and at room temperature the molecules do not have sufficient thermal energy to overcome the energy barrier. It is possibl...
by Dennisse Diaz 1D
Mon Jun 11, 2018 8:49 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: final [ENDORSED]
Replies: 4
Views: 245

Re: final [ENDORSED]

Molecular orbital (MO) theory is a method for determining molecular structure in which electrons are not assigned to individual bonds between atoms, but are treated as moving under the influence of the nuclei in the whole molecule.
by Dennisse Diaz 1D
Mon Jun 11, 2018 8:45 pm
Forum: Bond Lengths & Energies
Topic: antibond? [ENDORSED]
Replies: 2
Views: 117

Re: antibond? [ENDORSED]

An antibonding orbital is a type of molecular orbital (MO) that weakens the bond between two atoms and helps to raise the energy of the molecule relative to the separated atoms. Such an orbital has one or more nodes in the bonding region between the nuclei.
by Dennisse Diaz 1D
Mon Jun 11, 2018 8:44 pm
Forum: Administrative Questions and Class Announcements
Topic: Review Sessions Finals Week - Hedrick Hall? [ENDORSED]
Replies: 6
Views: 322

Re: Review Sessions Finals Week - Hedrick Hall? [ENDORSED]

There is a big review session tomorrow (Tuesday) in Dodd 147 at 11am that you can also consider attending.
by Dennisse Diaz 1D
Mon Jun 11, 2018 8:42 pm
Forum: Ionic & Covalent Bonds
Topic: ionic character
Replies: 11
Views: 950

Re: ionic character

Br has a stronger ionic character than iodine, therefore NaBr is stronger. You can tell apart the stronger ionization by going up and right in the periodic table.
by Dennisse Diaz 1D
Sun Jun 03, 2018 10:36 pm
Forum: Ionic & Covalent Bonds
Topic: lone pairs
Replies: 2
Views: 115

Re: lone pairs

As simple as The lone pairs are localized on the central atom. The lone pairs electrons in a molecule occupy more space as compared to the bonding pairs of electrons. This results in greater repulsion b/w lone pairs of electrons as compared to lone pair-bond pair and bond pair-bond pair repulsion.
by Dennisse Diaz 1D
Sun Jun 03, 2018 10:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 7
Views: 149

Re: VSEPR

This video has a lot of great information!!
https://www.bing.com/videos/search?q=ho ... ORM=VIREHT
by Dennisse Diaz 1D
Sun Jun 03, 2018 10:26 pm
Forum: Hybridization
Topic: hybridization of an atom
Replies: 2
Views: 83

Re: hybridization of an atom

Hybridization is the concept of mixing atomic orbitals into new hybrid orbitals (with different energies, shapes, etc., than the component atomic orbitals) suitable for the pairing of electrons to form chemical bonds in valence bond theory.
by Dennisse Diaz 1D
Mon May 28, 2018 3:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Drawing
Replies: 7
Views: 166

Re: VSEPR Drawing

You should know what the model looks like for you own self knowledge, but it is not required to draw it out during an exam. We only need to draw the 2D shape.
by Dennisse Diaz 1D
Mon May 28, 2018 1:15 am
Forum: Bond Lengths & Energies
Topic: Energies
Replies: 4
Views: 149

Re: Energies

The way you find the strongest or lowest energy is by finding the formal charges!!
Take the formal charge of every element in the molecule.
by Dennisse Diaz 1D
Mon May 28, 2018 1:07 am
Forum: Determining Molecular Shape (VSEPR)
Topic: VSPER MODEL
Replies: 3
Views: 71

Re: VSPER MODEL

I usually find the total number of electrons first and then begin to make a structure that will contain the lowest formal charge. It's usually guess and check for me.
-Guess the structure.
-Check the formal charge.
:)
by Dennisse Diaz 1D
Mon May 21, 2018 10:07 pm
Forum: Resonance Structures
Topic: 3.117
Replies: 2
Views: 154

3.117

Can someone please help explain parts a) b) c) of this question?
by Dennisse Diaz 1D
Sun May 20, 2018 10:02 pm
Forum: Resonance Structures
Topic: Stability
Replies: 3
Views: 83

Re: Stability

-Structures having filled octet a for second row elements (C, N, O, F) are stable.
-Structures having minimum number of formal charges and maximum number of bonds.
-Structure in which negative charge appears on the most electronegative atom (C < N < O).

Hope this helps a little!!
by Dennisse Diaz 1D
Sat May 19, 2018 3:05 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidation numbers
Replies: 4
Views: 160

Re: Oxidation numbers

To find oxidation numbers... 1) The oxidation number of a free element is always 0. 2) The oxidation number of a monatomic ion equals the charge of the ion. 3) The oxidation number of H is +1, but it is -1 in when combined with less electronegative elements. 4) The oxidation number of O in compounds...
by Dennisse Diaz 1D
Sat May 19, 2018 3:02 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidation numbers
Replies: 4
Views: 160

Re: Oxidation numbers

Oxidation numbers are numbers you assign to an element in chemical combination that represents the number of electrons lost (or gained, if the number is negative) by an atom of that element in the compound.
by Dennisse Diaz 1D
Sat May 19, 2018 3:01 pm
Forum: Ionic & Covalent Bonds
Topic: Radicals [ENDORSED]
Replies: 5
Views: 146

Re: Radicals [ENDORSED]

A radical is an atom, molecule, or ion that has an unpaired valence electron.
by Dennisse Diaz 1D
Sat May 19, 2018 3:00 pm
Forum: Resonance Structures
Topic: How does a resonance structure work?
Replies: 10
Views: 222

Re: How does a resonance structure work?

Resonance or mesomerism is a way of describing delocalized electrons within certain molecules or polyatomic ions where the bonding cannot be expressed by one single Lewis structure.
by Dennisse Diaz 1D
Sat May 19, 2018 2:59 pm
Forum: Ionic & Covalent Bonds
Topic: Octet rule
Replies: 17
Views: 367

Re: Octet rule

The octet rule is a chemical rule of thumb that reflects observation that atoms of main-group elements tend to combine in such a way that each atom has eight electrons in its valence shell, giving it the same electron configuration as a noble gas.
by Dennisse Diaz 1D
Thu May 17, 2018 12:10 am
Forum: Formal Charge and Oxidation Numbers
Topic: 3.49
Replies: 3
Views: 108

Re: 3.49

I'm sure they are asking for the octet due to the fact that this would make the molecule much more stable. What I don't understand is... Do we always have to draw the most stable molecule? Or can we submit a answer that is not in its MOST stable form?
by Dennisse Diaz 1D
Mon Apr 23, 2018 11:44 pm
Forum: Properties of Light
Topic: Question 1.57
Replies: 1
Views: 70

Question 1.57

How do you find the wavelength of the next line in the series?
I keep looking up YouTube videos, but they all use different equations and they skip the explanation. Can someone please go over how to find the next line in details?
-THANK YOU :)
by Dennisse Diaz 1D
Sun Apr 22, 2018 11:11 pm
Forum: Photoelectric Effect
Topic: Application of different formulas [ENDORSED]
Replies: 4
Views: 106

Re: Application of different formulas [ENDORSED]

I second this! The most confusing part for me is understanding when it is appropriate to use a certain formula. I am most confused about the all the formulas used in "Quantum". If posting all the formulas is too much, please post the ones used in quantum/ all the useful ones needed for thi...
by Dennisse Diaz 1D
Sun Apr 22, 2018 11:06 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Memorizing spectrum
Replies: 5
Views: 142

Re: Memorizing spectrum

Will any of these be provided during our quiz or midterm?
by Dennisse Diaz 1D
Sun Apr 22, 2018 11:03 pm
Forum: DeBroglie Equation
Topic: QM Description of Atoms
Replies: 2
Views: 59

Re: QM Description of Atoms

This is because electrons have electrostatic attractions and this can be seen through the line spectra that arises from transitions between discrete (quantized) energy states.
by Dennisse Diaz 1D
Sun Apr 15, 2018 9:53 pm
Forum: SI Units, Unit Conversions
Topic: Quiz 1
Replies: 6
Views: 248

Re: Quiz 1

The empirical formula would be the smallest ratio of the elements. For example if the molecular formula was C4H10, the empirical formula would be C2H5 (divided by a ratio of 2). Whereas the molecular formula tells you how many atoms are in that compound. -This was very helpful!! does this mean we h...
by Dennisse Diaz 1D
Sun Apr 15, 2018 9:51 pm
Forum: SI Units, Unit Conversions
Topic: chemical formula [ENDORSED]
Replies: 4
Views: 185

Re: chemical formula [ENDORSED]

I believe the 2 in 2Na is acting as a coefficient, so you would have 2 mols of Na whereas Na2 would change the structure of the atom. Na2 would be 2 Na bonded together while 2Na is still an unbound Na but in with a stochiometric coefficient so the ratios allow the chemical reaction to be balanced. ...
by Dennisse Diaz 1D
Sun Apr 15, 2018 9:35 pm
Forum: SI Units, Unit Conversions
Topic: Do we need to memorize unit conversions? [ENDORSED]
Replies: 9
Views: 1197

Re: Do we need to memorize unit conversions? [ENDORSED]

Does anyone know any helpful ways to memorize these conversions?
by Dennisse Diaz 1D
Sun Apr 15, 2018 9:33 pm
Forum: SI Units, Unit Conversions
Topic: chemical formula [ENDORSED]
Replies: 4
Views: 185

chemical formula [ENDORSED]

When writing a chemical formula/ equation, what is the difference between the placement of where the number goes? ... example: 2Na and Na2? I was very confused about this during quiz 1.
by Dennisse Diaz 1D
Sun Apr 15, 2018 9:25 pm
Forum: SI Units, Unit Conversions
Topic: Quiz 1
Replies: 6
Views: 248

Quiz 1

I am confused as to how to tell the difference between the empirical formula and the molecular formula... There was a question on the exam that gave multiple molecules and we had to give both the empirical and molecular formula, how do we find them? Someone help :(
by Dennisse Diaz 1D
Sun Apr 15, 2018 9:14 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical Reactions
Replies: 5
Views: 204

Re: Balancing Chemical Reactions

I am confused about how to balance an equation that involves fractions... An example is making 2Ca--> 5Ca. How would we go about this? I know you have to use fractions and then turn them into whole numbers, but I am still confused as to how to approach it and fully solve it.

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