Search found 52 matches

by Julianna Laurentano 4G
Sun Dec 08, 2019 4:59 pm
Forum: Biological Examples
Topic: en and edta
Replies: 5
Views: 51

Re: en and edta

Yes, but more specifically I would know what parts of their structures give them these characteristics and how you could identify other bidentates, hexadentates, etc.
by Julianna Laurentano 4G
Sun Dec 08, 2019 4:53 pm
Forum: Properties of Light
Topic: Light acting like a wave
Replies: 4
Views: 62

Re: Light acting like a wave

Diffraction patterns of light show that light can act like a wave, as well as constructive and destructive interference patterns.
by Julianna Laurentano 4G
Sun Dec 08, 2019 4:49 pm
Forum: Biological Examples
Topic: Heme complex
Replies: 5
Views: 69

Re: Heme complex

The heme complex consists of the central Fe atom and four CN groups; when the heme complex binds to a protein it forms hemoglobin, which helps in oxygen delivery throughout the body. Myoglobin is made up of several hemoglobin structures.
by Julianna Laurentano 4G
Sun Dec 08, 2019 4:45 pm
Forum: Biological Examples
Topic: chelating ligands
Replies: 3
Views: 43

Re: chelating ligands

Denticity describes the number of potential atoms that can bond to the central metal atom on the ligand. Polydentates are capable of forming chelating structures.
by Julianna Laurentano 4G
Sun Dec 08, 2019 4:43 pm
Forum: Dipole Moments
Topic: Hydrogen bonding AND Dipole-Dipole?
Replies: 3
Views: 40

Re: Hydrogen bonding AND Dipole-Dipole?

It might be, but it's good to include both to demonstrate that there are other potential atoms involved besides H, N, O, F, etc.
by Julianna Laurentano 4G
Sun Dec 01, 2019 11:59 am
Forum: Conjugate Acids & Bases
Topic: Conjugate Base
Replies: 5
Views: 56

Re: Conjugate Base

This is because strong acids dissociate completely; HCl, for example, completely dissociates into H+ and Cl-, so a weak conjugate base would have no impact on this.
by Julianna Laurentano 4G
Sun Dec 01, 2019 11:54 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Strong and Weak Acids
Replies: 7
Views: 57

Re: Strong and Weak Acids

I would definitely familiarize yourself with a list of both the common weak and strong acids before the final. However, a good rule to test is that strong acids can completely dissociate in a solution, while weak acids can only partly dissociate. For example, HCl, a strong acid, can fully dissociate...
by Julianna Laurentano 4G
Sun Dec 01, 2019 11:51 am
Forum: Amphoteric Compounds
Topic: Identifying Them?
Replies: 12
Views: 78

Re: Identifying Them?

An amphoteric compound is one that can both accept and donate electrons when need be, so I would test the compound to see if that is the case. For example, H2O can accept an electron to become H3O+ or it can donate an electron to become OH- depending on the problem. Additionally, amphoteric molecule...
by Julianna Laurentano 4G
Sun Dec 01, 2019 11:45 am
Forum: Naming
Topic: Not Counting Subscripts?
Replies: 2
Views: 28

Re: Not Counting Subscripts?

The tri is referring to the number of ammonia molecules; since there are only three, the name remains triaminetriaquacobalt.
by Julianna Laurentano 4G
Sun Dec 01, 2019 11:43 am
Forum: Naming
Topic: Coordination compounds
Replies: 2
Views: 34

Re: Coordination compounds

Definitely refer to the resource source the previous commenter posted!
To summarize it quickly, coordination compounds are those molecules that consist of one or multiple metal center atoms bound to ligands.
by Julianna Laurentano 4G
Sun Nov 24, 2019 6:57 pm
Forum: Biological Examples
Topic: Drawing Structures on Final
Replies: 3
Views: 58

Re: Drawing Structures on Final

I would assume that we should know the structures of the examples Dr. Lavelle covered in depth in class, since those relate strongly to the key concepts covered.
by Julianna Laurentano 4G
Sun Nov 24, 2019 6:54 pm
Forum: Einstein Equation
Topic: e = hv
Replies: 1
Views: 51

Re: e = hv

The formula relates the energy of a photon is to its frequency; the energy is directly proportional to the frequency. Therefore, as the frequency of a particle increases, so does its energy.
by Julianna Laurentano 4G
Sat Nov 23, 2019 9:08 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Hydrogen bond Strength
Replies: 3
Views: 35

Re: Hydrogen bond Strength

Out of the bonds, hydrogen is the strongest, and London (or dipole-induced dipole) forces are the weakest. When the hydrogen atom binds to an extremely electronegative atom (N, O, or F), it's only electron is pulled in very close, reducing the atomic radius and therefore forming a very stable bond.
by Julianna Laurentano 4G
Sat Nov 23, 2019 5:09 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Transition Metals
Replies: 2
Views: 25

Re: Transition Metals

In an organometallic compound, there is at least one bond between a carbon (that's part of an organic molecule) and a metal.
by Julianna Laurentano 4G
Sat Nov 23, 2019 4:53 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: What are coordination compounds
Replies: 2
Views: 33

Re: What are coordination compounds

Coordination compounds possess a chemical structure in which the central atom, a metal, has nonmetal atoms bonded to it by chemical bonds. These nonmetal atoms donate electrons to the metal. Coordination compounds are produced by Lewis acid-base reactions.
by Julianna Laurentano 4G
Sat Nov 23, 2019 4:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Final exam
Replies: 17
Views: 217

Re: Final exam

Yes, the final will be on all material covered from weeks 1-10!
by Julianna Laurentano 4G
Sun Nov 17, 2019 1:56 pm
Forum: Hybridization
Topic: Test?
Replies: 6
Views: 58

Re: Test?

I don't believe hybridization will be on the test. Dr. Lavelle said on Friday there was one more slide from tomorrow's lecture that will be on the test and I believe that it's related to sigma and pi bonds.
by Julianna Laurentano 4G
Sun Nov 17, 2019 1:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Angles to know for test 2
Replies: 3
Views: 41

Re: Angles to know for test 2

I would know the corresponding angle measurements for all the examples Dr. Lavelle went over during the past two lectures. I would also know what conditions make the angles slightly less than the usual measure.
by Julianna Laurentano 4G
Sat Nov 16, 2019 6:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E 1 b)
Replies: 2
Views: 32

Re: 2E 1 b)

A linear molecule can have no lone pairs or it can have lone pairs. Since the angle remains at 180 degrees, these lone pairs must be oriented in such a way that they cancel out, permitting the bond angle to remain at 180. This often found on central atoms possessing three or four lone pairs of elect...
by Julianna Laurentano 4G
Sat Nov 16, 2019 6:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Different Types of Bonds
Replies: 2
Views: 24

Re: Different Types of Bonds

The VSEPR model takes the number of electron density regions into consideration, and since single, double, and triple bonds are all considered just one region of electron density, they are treated equally. Because of this, the resonance structure used to determine the VSEPR model does not matter.
by Julianna Laurentano 4G
Fri Nov 15, 2019 10:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 6
Views: 37

Re: Bond Angles

When there is a lone pair on the central atom, the bond angle is slightly less. This is because the lone pair of electrons on the central atom forces the bonding electrons closer together, therefore distorting the angle.
by Julianna Laurentano 4G
Thu Nov 14, 2019 1:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.7
Replies: 2
Views: 28

Re: 2E.7

The fact that the S atom has three bonds and a lone pair slightly affects the bond angles; instead of being exactly 109.5 degrees, we can expect the angles to be slightly less than 109.5 degrees. This is because the lone pair of electrons repels the shared pairs, causing a slight displacement in the...
by Julianna Laurentano 4G
Sun Nov 10, 2019 2:23 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 4
Views: 36

Re: Polarizability

Polarizability increases down a column because the atomic radius increases down a column, and large molecules are more polarizable. Polarizability also decreases across a period because there is an increase in the effective nuclear charge across a period, and cations are smaller than neutral atoms. ...
by Julianna Laurentano 4G
Sun Nov 10, 2019 2:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Discussion-Week 9
Replies: 3
Views: 48

Re: Discussion-Week 9

I believe that if you have discussion on Monday-Wednesday you will still have it, as my TA mentioned during our Thursday discussion that the reason why we met during week zero (in which classes were only on Thursday and Friday) was to make up for not meeting during the week of Thanksgiving. However,...
by Julianna Laurentano 4G
Sun Nov 10, 2019 1:41 pm
Forum: Dipole Moments
Topic: Dipoles between the same elements
Replies: 3
Views: 45

Re: Dipoles between the same elements

Dipoles do not occur between atoms of the same element; dipoles are due to an uneven distribution of electrons, so one atom must possess a different distribution than the other. Dipoles occur between two different nonmetals that are unevenly sharing electrons.
by Julianna Laurentano 4G
Sun Nov 10, 2019 1:38 pm
Forum: Lewis Acids & Bases
Topic: Why Lewis Acid?
Replies: 3
Views: 40

Re: Why Lewis Acid?

According to Lewis, acids accept pairs of electrons while bases donate them. Using H2O as an example, Lewis said that the H+ is the atom that actively accepts electrons from OH-, forming H2O.
by Julianna Laurentano 4G
Sun Nov 10, 2019 1:34 pm
Forum: Coordinate Covalent Bonds
Topic: Coordinate Covalent Bond
Replies: 8
Views: 86

Re: Coordinate Covalent Bond

In a regular covalent bond, the two nuclei of the two atoms attract one another. In a coordinate covalent bond, one of the atoms donates both electrons, making it a bit weaker than a regular covalent bond.
by Julianna Laurentano 4G
Sun Nov 03, 2019 5:53 pm
Forum: Lewis Structures
Topic: Names
Replies: 4
Views: 45

Re: Names

I believe that if we are given a more uncommon molecular formula like this, Dr. Lavelle will provide us with chemical formula as well. If not, I'm sure you could ask a TA for clarification.
by Julianna Laurentano 4G
Sun Nov 03, 2019 5:44 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework Due this week
Replies: 2
Views: 34

Re: Homework Due this week

Homework problems are always related to the material most recently covered in class, so I would assume completing any problems from Chemical Bonds is okay.
by Julianna Laurentano 4G
Sun Nov 03, 2019 5:33 pm
Forum: Einstein Equation
Topic: eV
Replies: 4
Views: 79

Re: eV

It stands for megaelectronvolt, so I would convert it to eV (1 meV= 1000000ev) and then convert it to Joules.
by Julianna Laurentano 4G
Sun Nov 03, 2019 5:30 pm
Forum: Photoelectric Effect
Topic: Work function of an atom
Replies: 4
Views: 48

Re: Work function of an atom

The question is asking for the energy emitted by the electron, so I would use the equations c=wavelength * frequency and E=hv to calculate the correct energy. It is not asking for the kinetic energy or the work function, so you do not need to use 1/2mv^2 in order to solve the problem.
by Julianna Laurentano 4G
Sun Nov 03, 2019 5:28 pm
Forum: Bond Lengths & Energies
Topic: Next Lecture
Replies: 3
Views: 37

Re: Next Lecture

I believe in lecture he said we will be doing review problems for the midterm. If we cover any new material it won't be on the midterm.
by Julianna Laurentano 4G
Sun Oct 27, 2019 3:00 pm
Forum: Trends in The Periodic Table
Topic: Netural atoms.
Replies: 2
Views: 36

Re: Netural atoms.

When we compare to the neutral atom, is it easy to determine if there was a loss or gain in electrons due to the positive or negative charge of the given ion. In the neutral state, the number of electrons equals the number of protons, so if there is a change in the net charge of the atom, it becomes...
by Julianna Laurentano 4G
Sun Oct 27, 2019 2:56 pm
Forum: Trends in The Periodic Table
Topic: The Inert Pair Effect
Replies: 2
Views: 23

Re: The Inert Pair Effect

Basically the inert pair effect is when electrons in the outer s orbital remain unionized, and this is because there is poor shielding of these orbitals, so they cannot form bonds. As a result, these electrons remain unionized.
by Julianna Laurentano 4G
Sun Oct 27, 2019 2:24 pm
Forum: Trends in The Periodic Table
Topic: Cations
Replies: 8
Views: 50

Re: Cations

Cations are smaller than their parent atoms because they have less electrons. Cations are positively charged ions, so when they lose their electrons, the remaining electrons move closer to the nucleus, and the size of the cation is reduced.
by Julianna Laurentano 4G
Sun Oct 27, 2019 2:13 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic vs. Atomic Radii
Replies: 4
Views: 43

Re: Ionic vs. Atomic Radii

The atomic radius is half the diameter of the atom. The ionic radius is half the distance between two atoms that are touching. So, the ionic radius involves two atoms, while the atomic radius is just the radius of the singular atom.
by Julianna Laurentano 4G
Sun Oct 27, 2019 2:05 pm
Forum: Properties of Light
Topic: Value for C
Replies: 8
Views: 77

Re: Value for C

During my discussions we have been using 3.00x10^8, but as long as your final answer is rounded to the correct number of significant figures I'm sure either is fine to use!
by Julianna Laurentano 4G
Sat Oct 19, 2019 2:18 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Tips for the Midterm
Replies: 10
Views: 84

Re: Tips for the Midterm

I would definitely star the topics that are a bit confusing and read about them in the textbook in addition to completing the corresponding homework problems for them! I would also review the problems done for practice in discussion section, as those cover the basic concepts. Additionally, the modul...
by Julianna Laurentano 4G
Sat Oct 19, 2019 2:12 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Coulomb's Law
Replies: 3
Views: 36

Re: Coulomb's Law

Coulomb's Law refers to the force created between two charged objects (the force that two electrons exert on each other, in this case). According to Coulomb's law, the force that is exerted is inversely proportional to the distance between the object, which is why there is a weaker force for electro...
by Julianna Laurentano 4G
Sat Oct 19, 2019 2:05 pm
Forum: *Shrodinger Equation
Topic: derivation
Replies: 5
Views: 45

Re: derivation

I don't think we would be given problems where we have to derive the equations (especially since we are given a formula sheet for exams), but knowing the general basis of the derivation is definitely helpful in understanding the main concepts behind the equation. I would know how each variable relat...
by Julianna Laurentano 4G
Fri Oct 18, 2019 12:17 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Equation
Replies: 4
Views: 36

Re: Rydberg Equation

The Rydberg formula is used to calculate the wavelength of light produced by an electron that is moving between energy levels (between orbitals). So, when a question surrounds the movement of electrons between different orbitals (AKA there is a change in energy), you apply Rydberg's formula, pluggin...
by Julianna Laurentano 4G
Fri Oct 18, 2019 12:09 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 10
Views: 78

Re: Nodal Planes

A nodal plane is a plane where there are no electrons (zero percent chance of finding an electron there). An example is the 2p orbital!
by Julianna Laurentano 4G
Sun Oct 13, 2019 4:18 pm
Forum: Properties of Light
Topic: Intensity of light
Replies: 2
Views: 30

Re: Intensity of light

The intensity of light is determined by the light waves amplitude (vertical extent on a graph).
Therefore, to increase the intensity of light, increase its amplitude.
by Julianna Laurentano 4G
Sun Oct 13, 2019 4:08 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: atomic spectra
Replies: 5
Views: 73

Re: atomic spectra

Excited atoms give off light of various wavelengths, and these wavelengths respond to different colors, as we saw in class. When this data is observed, the set of colored lines produced is referred to as the atomic spectra. In my class notes, I wrote: "spectroscopic analysis of light given off ...
by Julianna Laurentano 4G
Fri Oct 11, 2019 12:29 pm
Forum: Empirical & Molecular Formulas
Topic: Mass Percentage Question
Replies: 9
Views: 263

Re: Mass Percentage Question

Begin by finding the total molar mass of Sr(NO2)2. Then, find the mass of each element and divide that by the total molar mass of Sr(NO2)2 to obtain each percentage. Make sure that your calculations include 1 Sr atom, 2 N atoms, and 4 O atoms.
by Julianna Laurentano 4G
Thu Oct 10, 2019 2:47 pm
Forum: SI Units, Unit Conversions
Topic: Angstrom
Replies: 16
Views: 250

Re: Angstrom

You will be given a formula sheet for the test that could potentially list the units (there's a chance it might not, however), so just in case I would definitely familiarize yourself with the units of measurement and what value they have (1 Angstrom= 10^-10 meters).
by Julianna Laurentano 4G
Thu Oct 10, 2019 2:44 pm
Forum: Significant Figures
Topic: Conflicting Sig Fig Advice
Replies: 3
Views: 77

Re: Conflicting Sig Fig Advice

My TA told our class during our first meeting that as long as your final answer was rounded to the correct number of significant figures, then you will receive full credit. I don't believe each number in your calculation needs to be correctly rounded as long as you make sure your final answer is.
by Julianna Laurentano 4G
Thu Oct 03, 2019 2:45 pm
Forum: Significant Figures
Topic: Sig Figs for Adding
Replies: 2
Views: 48

Re: Sig Figs for Adding

I believe that first you would add the two numbers together, and then you would round the final answer to the least number of significant figures present in any part of the problem (so in this case, round to the tenths place). Today in discussion, my TA mentioned that it is most important that our f...
by Julianna Laurentano 4G
Thu Oct 03, 2019 2:36 pm
Forum: Limiting Reactant Calculations
Topic: M. 11) Limiting Reactant
Replies: 2
Views: 60

Re: M. 11) Limiting Reactant

Essentially, you solve for the limiting reactant twice. Using the first equation, determine the limiting reactant (O2) and how much is produced. Using the amount of P4 in the equation, calculate the moles of P4O6 produced by multiplying by the molar ratio. With this information, the limiting reactan...
by Julianna Laurentano 4G
Thu Oct 03, 2019 2:24 pm
Forum: Significant Figures
Topic: Sig Figs
Replies: 4
Views: 53

Re: Sig Figs

I would definitely take sig figs into account for the entire problem, as it will ensure that you do not forget to round correctly at the end. Today my TA informed my class that it is most important that our final answer is rounded to the correct number of significant figures (and not necessarily eve...
by Julianna Laurentano 4G
Thu Oct 03, 2019 8:19 am
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula Purpose
Replies: 13
Views: 192

Re: Empirical Formula Purpose

Empirical formulas are used to display the lowest whole-number ratio of all the atoms involved in the compound; it simply shows the basic ratio that the molecular formula is a certain multiple of.
by Julianna Laurentano 4G
Thu Oct 03, 2019 8:15 am
Forum: Balancing Chemical Reactions
Topic: balancing reaction law
Replies: 4
Views: 298

Re: balancing reaction law

As stated above, you cannot add reactants or products to the chemical equation, as the total mass before must equal the total mass after. However, you may use coefficients to make sure each side of the reaction is balanced in respect to the atoms of each element.

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