Search found 31 matches

by Ethan McCarthy 1F
Wed Jul 31, 2019 8:01 am
Forum: Ionic & Covalent Bonds
Topic: Boiling Point
Replies: 4
Views: 324

Re: Boiling Point

Strength and type of intermolecular forces (ion-ion, ion-dipole, dipole-dipole, dipole-induced dipole, induced dipole-induced dipole), as well as the shape of the molecule (rod-shaped [allows for dipoles to be closer together] vs. spherical) affects the boiling point. The stronger the intermolecular...
by Ethan McCarthy 1F
Wed Jul 31, 2019 7:56 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Formal Charge
Replies: 9
Views: 397

Re: Formal Charge

I believe the more electronegative atom of the two involved in a bond would be the more likely atom to have the negative formal charge. However, I'm not sure if the opposite is true for the positive formal charges.
by Ethan McCarthy 1F
Wed Jul 31, 2019 7:53 am
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 2
Views: 161

Re: VSEPR

The VSEPR formula denotes the number of atoms and lone pairs connected to the central atom using ambiguous letters and numbers (A, X, and E, which still inform us of the molecule's geometry and shape). A = the central atom X = the number of atoms bonded to the central atom E = the number of lone pai...
by Ethan McCarthy 1F
Wed Jul 31, 2019 7:48 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: Polar v nonPolar
Replies: 4
Views: 454

Re: Polar v nonPolar

Polarity depends on the difference between the electronegativities of two atoms connected by a covalent bond. If one of the atoms (like oxygen in H2O) has a high electronegativity, then it pulls electrons away from the atoms with a lower electronegativity (like hydrogen in this case).
by Ethan McCarthy 1F
Wed Jul 31, 2019 1:24 am
Forum: Naming
Topic: Cation/Anion
Replies: 3
Views: 182

Re: Cation/Anion

You can also tell which elements are prone to forming cations/anions based on their location on the periodic table. Elements on the left side typically lose electrons to reach the same valence shell as the noble gases (full valence shell). Losing electrons (which have a negative charge) results in a...
by Ethan McCarthy 1F
Wed Jul 31, 2019 1:15 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: edta
Replies: 7
Views: 506

Re: edta

I think my TA said that we won't be expected to know the structure of edta but we should know the molecular formula (which should be: [C₁₀H₁₂O₈N₂]⁴⁻).
by Ethan McCarthy 1F
Wed Jul 31, 2019 12:26 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Formula from Name
Replies: 4
Views: 193

Re: Formula from Name

For coordination compounds the formula from name typically looks something like this: _cation_[transition metal_(first ligand)__(second ligand)]__anion__ Just make sure you organize the ligands (first, second,...) alphabetically. An example would be diamminedichloroplatinum(IV) chloride: [Pt(NH 3 ) ...
by Ethan McCarthy 1F
Wed Jul 31, 2019 12:15 am
Forum: Naming
Topic: CO3(2-) Carbanato
Replies: 2
Views: 178

Re: CO3(2-) Carbanato

I'm not sure about what the prefix for carbonato is, but where did you learn that it was both monodentate and bidentate? I've just been assuming it's monodentate :/
by Ethan McCarthy 1F
Tue Jul 30, 2019 9:32 pm
Forum: Resonance Structures
Topic: Delocalization
Replies: 6
Views: 516

Re: Delocalization

Does delocalization only occur on molecules with resonance?
by Ethan McCarthy 1F
Tue Jul 30, 2019 9:30 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Hydrates
Replies: 1
Views: 171

Hydrates

When should hydrates be added to a coordination compound? When they are added they don't factor into the coordination number, right?
by Ethan McCarthy 1F
Tue Jul 30, 2019 9:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Tetrahedral geometry with two lone pairs
Replies: 1
Views: 153

Tetrahedral geometry with two lone pairs

In an AX2E2 molecule can the two lone pairs cancel to allow for a linear shape, or will the molecule always be bent?
by Ethan McCarthy 1F
Tue Jul 30, 2019 9:21 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate ligands and coordination number/structure
Replies: 1
Views: 156

Polydentate ligands and coordination number/structure

Does a polydentate ligand bound to the central atom multiple times affect the coordination number? Or should we just count the number of bonds the central atom has coming from it?
by Ethan McCarthy 1F
Tue Jul 30, 2019 9:12 pm
Forum: Dipole Moments
Topic: Lone pairs and hydrogen bonding
Replies: 3
Views: 183

Lone pairs and hydrogen bonding

Are lone pairs required for hydrogen bonding to occur or is it just that lone pairs tend to exist in molecules that can hydrogen bond because these molecules are more likely to have dipole moments?
by Ethan McCarthy 1F
Tue Jul 30, 2019 9:07 pm
Forum: Conjugate Acids & Bases
Topic: Delocalization of charge and stability
Replies: 2
Views: 346

Delocalization of charge and stability

When we say the conjugate base is more stable because it better delocalizes the charge (when comparing two acids and their conjugate bases), what does this mean?
by Ethan McCarthy 1F
Tue Jul 30, 2019 9:02 pm
Forum: Lewis Acids & Bases
Topic: Spectator Ions
Replies: 1
Views: 166

Re: Spectator Ions

You can tell when you write out the net ionic equation and the ion is "by itself" (not part of a molecule) as both a product and a reactant. Like in a reaction between NaOH and HCl, I believe both Na and Cl would both be considered spectator ions since they would remain Na+ and Cl- ions wh...
by Ethan McCarthy 1F
Mon Jul 15, 2019 12:28 am
Forum: Ionic & Covalent Bonds
Topic: Radicals
Replies: 7
Views: 380

Re: Radicals

I'm not completely sure of the formation of radicals, but in lecture Professor Lavelle mentioned that radicals are highly reactive and only exist for a short time. He said that they are often involved in reactions which I believe means that radicals are often intermediates in a series of reactions.
by Ethan McCarthy 1F
Mon Jul 15, 2019 12:23 am
Forum: Formal Charge and Oxidation Numbers
Topic: Difference between charge and formal charge [ENDORSED]
Replies: 4
Views: 378

Re: Difference between charge and formal charge [ENDORSED]

Formal charge is the charge assoicated with each atom in a molecule, while the general charge you are referring to (the molecule's net charge) is the sum of all of the individual atoms' formal charge. In the case of [SO4], I believe the charge is 2-, which reflects an accurate sum of the formal char...
by Ethan McCarthy 1F
Mon Jul 15, 2019 12:19 am
Forum: Lewis Structures
Topic: Aluminum and Boron [ENDORSED]
Replies: 2
Views: 259

Re: Aluminum and Boron [ENDORSED]

From the example in lecture (with BF3), the fluorine is more electronegative than the boron, so when finding the most stable Lewis diagram for BF3 we use electronegativity to determine that fluorine is unlikely to give up electrons to fill the valence shell of boron (the less electronegative atom). ...
by Ethan McCarthy 1F
Mon Jul 15, 2019 12:12 am
Forum: Ionic & Covalent Bonds
Topic: What to do if electronegativity difference is between 1.5 and 2? [ENDORSED]
Replies: 3
Views: 246

Re: What to do if electronegativity difference is between 1.5 and 2? [ENDORSED]

When the electronegativity difference is larger than two, there is an ionic bond between the two atoms and when the electronegativity difference is less than 1.5 then we can be sure there is a covalent bond between the two atoms. These values can guide us to the type of bond when the values are give...
by Ethan McCarthy 1F
Mon Jul 15, 2019 12:02 am
Forum: Lewis Structures
Topic: Ionic Bond Structures [ENDORSED]
Replies: 2
Views: 266

Re: Ionic Bond Structures [ENDORSED]

In my discussion, the TA drew ionic compounds with brackets like: [Na]+[Cl]- so from what I understand this would be the appropriate representation of the ionic bond. The example the TA used in discussion was [H]+[SO4]2-[H]+ where [SO4]2- had the Lewis structure for SO4 within the brackets (since it...
by Ethan McCarthy 1F
Sun Jul 14, 2019 11:58 pm
Forum: Lewis Structures
Topic: Formal Charge [ENDORSED]
Replies: 2
Views: 272

Re: Formal Charge [ENDORSED]

Formal charge is a charge calculated for each atom in a molecule, used to determine the most stable structure for the molecule. Formal charge must be close to zero (or +/-1) because neutral charges are the most favorable.
by Ethan McCarthy 1F
Sun Jul 14, 2019 11:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Test #2
Replies: 2
Views: 219

Re: Test #2

I believe test two should only cover bonding (including material from lecture tomorrow, July 15th).
by Ethan McCarthy 1F
Thu Jul 04, 2019 7:14 pm
Forum: Quantum Numbers and The H-Atom
Topic: Energy of different energy shell
Replies: 1
Views: 178

Re: Energy of different energy shell

The lower the principal quantum number (n) the lower the energy of the electron. This means that lower energy shells contain electrons with less energy. When an electron becomes excited and "jumps" to the next energy level (i.e. n=1 to n=2), the electron has gained energy. When the electro...
by Ethan McCarthy 1F
Thu Jul 04, 2019 7:04 pm
Forum: Properties of Light
Topic: Main experimental results
Replies: 2
Views: 212

Re: Main experimental results

The way I understood the concept was that the amplitude of the light is associated with its intensity. This is a property of waves, so when increasing the intensity/amplitude of the light did not result in electrons being ejected from the metal (in all the experiments), the experiment suggested that...
by Ethan McCarthy 1F
Thu Jul 04, 2019 4:42 pm
Forum: Properties of Light
Topic: textbook question
Replies: 2
Views: 173

Re: textbook question

I believe the question is asking for us to convert the values given in the table to fill in for the missing values. For instance, the table gives the frequency 8.7x10^(14) Hz, so it is asking us to calculate the corresponding wavelength, energy of the photon, and match to the corresponding event (i....
by Ethan McCarthy 1F
Sun Jun 30, 2019 4:03 pm
Forum: Limiting Reactant Calculations
Topic: Dividing by the Stoichiometric Coefficient
Replies: 2
Views: 212

Dividing by the Stoichiometric Coefficient

Once we calculate how many moles of one of the reactants (from grams -> moles with the molar mass), we can divide by the stoichiometric coefficient of the reactant (taken from the balanced chemical equation). When you divide the moles of the reactant by its stoichiometric coefficient, what does the ...
by Ethan McCarthy 1F
Sun Jun 30, 2019 3:53 pm
Forum: Properties of Light
Topic: Technical Names for Light
Replies: 1
Views: 166

Re: Technical Names for Light

I believe we should be ok by referencing the above types of light as "ultraviolet" and "visible" light. If you're asking about the approximate values/ranges of the wavelengths for each type of light, UV is around ~350nm while visible light is about 500nm (these values are within ...
by Ethan McCarthy 1F
Sun Jun 30, 2019 3:00 pm
Forum: Photoelectric Effect
Topic: Threshold Energy
Replies: 2
Views: 214

Re: Threshold Energy

The threshold energy may be given in the problem. For instance, in the example Dr. Lavelle used in lecture on Friday, "If 3.61x10^-19J is required to remove an electron with zero kinetic energy from a metal surface, what would be the longest wavelength of light to do this?". Here the note ...
by Ethan McCarthy 1F
Sun Jun 30, 2019 2:51 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Spectral Lines and Energy Levels
Replies: 3
Views: 235

Spectral Lines and Energy Levels

When looking at the groups of spectral lines (i.e. the Lyman series), which line represents the lowest energy level? Is it the line with the widest gap or shortest gap?
by Ethan McCarthy 1F
Sun Jun 30, 2019 2:46 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Element "Fingerprinting"
Replies: 1
Views: 186

Atomic Spectra Element "Fingerprinting"

To use atomic spectroscopy to identify an element, one wavelength of light is directed towards an element and if the light passes through, the element doesn't interact with that wavelength. If the wavelength does interact with the element, we can measure the wavelength of the light emitted from the ...
by Ethan McCarthy 1F
Sun Jun 30, 2019 2:22 pm
Forum: Empirical & Molecular Formulas
Topic: Naming Compounds
Replies: 1
Views: 174

Naming Compounds

Does anyone know of ways/mnemonics to remember the formula associated with polyatomic anions (especially oxoanions)? Table D.1 on page F30 of the seventh ed. textbook has many examples of the names of anions and the formula, so I'm wondering if it's best for me to memorize the table or if there's a ...

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