Search found 35 matches

by Michelle Fu 1H
Fri Jan 25, 2019 5:57 pm
Forum: Phase Changes & Related Calculations
Topic: Sublimation
Replies: 6
Views: 116

Sublimation

Last unit we talked about how increasing pressure would push the equilibrium towards the side with less moles or more compact molecules, thus creating more solids in some cases. I was wondering in cases which two gases go straight to a solid how it bypasses the step of turning into a liquid, like wa...
by Michelle Fu 1H
Thu Jan 24, 2019 4:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: HW 12.69 Q about spectator ions
Replies: 1
Views: 49

HW 12.69 Q about spectator ions

I understand the concept of spectator ions but I don't understand how to "break up" compounds to make acids or bases. For example: AlCl3 2AlCl3 + 3H2O = Al2O3 (s) + 6HCl How do you know it doesn't break up like AlCl3+ 3H2O = Al(OH)3 + 3HCl instead? Does it make a difference which one you u...
by Michelle Fu 1H
Tue Jan 22, 2019 5:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Making more product
Replies: 3
Views: 51

Making more product

On the module question 16 says that making a reaction go faster does not make more product at equilibrium. I now realize this fact, but I was wondering what change in conditions makes more product?
by Michelle Fu 1H
Wed Jan 16, 2019 1:26 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solving Cubics [ENDORSED]
Replies: 1
Views: 416

Solving Cubics [ENDORSED]

I know in the module Dr. Lavelle solved ICE tables involving cubics using the fact the change in X is small because the K value is small. However, what if the K value was large? How would we go about solving the cubic then? Are we expected to know how to for the exam?
by Michelle Fu 1H
Wed Jan 16, 2019 1:19 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Post Assessment
Replies: 1
Views: 52

Re: Post Assessment

No, the part that you're getting mixed up with is balancing the equation

The correctly balanced equation should be 2NO2 (g) + 7H2 (g) ⇌ 2NH3 (g) + 4H2O(l)

Therefore the correct answer should be: (NH3)^2/(((H2)^7)(NO2)^2)
by Michelle Fu 1H
Mon Jan 14, 2019 5:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Acids and Bases
Replies: 7
Views: 124

Re: Acids and Bases

While it is good to memorize specifically which are acids and bases, there are a couple of indicators for just figuring it out yourself Strong acids: Generally a H+ ion with a nonmetal with a large radius, such as HCl or HBr, oxyacids (acids with oxygen) with more oxygen (for example, HNO3 is a stro...
by Michelle Fu 1H
Wed Jan 09, 2019 11:32 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Stability
Replies: 3
Views: 43

Re: Stability

It depends on the K. When the products are more stable more will be produced, meaning that the K will be larger. When the reactants are more stable they will wish to not react as much, thus there will be more reactants and thus K will be smaller. So to answer your question, no, the product is not al...
by Michelle Fu 1H
Wed Jan 09, 2019 9:08 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pressure when given temp and time
Replies: 1
Views: 42

Re: pressure when given temp and time

I'd assume you use PV = nRT. In the first part of the problem you are given the pressure, R and the temperature which are P, R, and T respectively. The key thing here is to solve for n, and we do that by moving everything to the left side of the equation: PV/RT = n We know that the number of moles i...
by Michelle Fu 1H
Mon Jan 07, 2019 9:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and Liquids and the K expression
Replies: 2
Views: 80

Solids and Liquids and the K expression

Why aren't solids and liquids included in the K expression? I didn't completely understand Dr. Lavelle's explanation.
by Michelle Fu 1H
Sun Dec 02, 2018 7:26 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Drawing Chelates
Replies: 1
Views: 63

Drawing Chelates

When we are given a coordination compound to draw, generally what are the steps to draw a chelate? I feel that I would be confused on which atoms would attach to each other.
by Michelle Fu 1H
Sun Dec 02, 2018 6:47 pm
Forum: Naming
Topic: Naming
Replies: 2
Views: 54

Re: Naming

When it comes to naming coordination compounds, the order is determined alphabetically. Note that we ignore the greek prefixes when it comes to ordering.
by Michelle Fu 1H
Wed Nov 28, 2018 12:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Correct Bond Angles
Replies: 6
Views: 146

Correct Bond Angles

So I was checking my HW and noticed that there is discrepancies between the angles accepted by the textbook and online guides for VSEPR angles. For example, the accepted angles found in the seesaw molecular shape is 120 and 90, yet most online sources list to angles to be slightly less in both. I wa...
by Michelle Fu 1H
Sun Nov 25, 2018 5:06 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Drawing VSEPR
Replies: 2
Views: 60

Re: Drawing VSEPR

To clarify further - no, there are no resonance structures when drawing VSEPR
by Michelle Fu 1H
Sun Nov 25, 2018 5:04 am
Forum: Hybridization
Topic: pi and sigma bonds
Replies: 3
Views: 53

Re: pi and sigma bonds

To give a explanation in laymans terms: SIGMA BOND 1) side to side overlap 2) always present in single bonded molecules. 3) It has low energy and most stability and considered as covalent bond which is property of covalent compounds. Pi BOND 1)head to head overlapping of orbitals. 2) present in doub...
by Michelle Fu 1H
Sun Nov 25, 2018 4:53 am
Forum: Hybridization
Topic: Hybridization when dealing with pi and sigma bonds
Replies: 1
Views: 45

Re: Hybridization when dealing with pi and sigma bonds

Hybridized orbitals are traditionally used only for sigma bonds, because they allow an s orbital to be transformed into something that points in a particular direction.
by Michelle Fu 1H
Sun Nov 18, 2018 6:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Geometry
Replies: 6
Views: 107

Re: Molecular Geometry

In reference when making VSEPR models, it is important to note that electron density geometry affect molecular geometry, specifically the bond angle. As a general rule of thumb, the more lone pairs the more "pressure" these lone pairs will exert on the geometry.
by Michelle Fu 1H
Sun Nov 18, 2018 5:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Electrostatic potential
Replies: 2
Views: 74

Re: Electrostatic potential

Electrostatic potential is also shown through electrostatic potential surfaces, where the net electric potential is calculated at each point and depicted by different colors. Blue is positive potential at that point and red means the opposite.
by Michelle Fu 1H
Sat Nov 17, 2018 6:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Pyramidal and it's consequences
Replies: 1
Views: 55

Trigonal Pyramidal and it's consequences

So other than Trigonal Pyramidal shape, all other shapes have equivalent angles between regions of electron density. What consequences (physical, chemical etc) does the fact that trigonal pyramidal shape has all different angles have, if any?
by Michelle Fu 1H
Sun Nov 11, 2018 4:04 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 Bonding Question
Replies: 3
Views: 55

Hydrogen Bonding Question

Why is the hydrogen bond so much stronger than other Van Der Waals forces? Also why is the energy -20 kJ per mole as opposed to just 20 kJ?
by Michelle Fu 1H
Sun Nov 11, 2018 4:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Hydrogen Bonding
Replies: 7
Views: 139

Re: Hydrogen Bonding

The typical attractive energy is around 20 kJ per mol. Note that this attractive energy quite high compared to other Van Der Waals forces such as dipole dipole and dispersion but still less than covalent bonding.
by Michelle Fu 1H
Sun Nov 11, 2018 3:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 7
Views: 129

Re: Lone Pairs

After some quick googling (as I don't think we have covered this subject in class yet) it seems that unpaired electrons do have a effect on the VSEPR models in that they alter the angle. For example, if there are two bonding groups and zero unpaired, the geometry is linear, but if there is 1 lone pa...
by Michelle Fu 1H
Sun Nov 04, 2018 11:55 pm
Forum: Trends in The Periodic Table
Topic: Ranking of effects on Periodic trends
Replies: 1
Views: 68

Ranking of effects on Periodic trends

So I know the general trends of the periodic table in regards to ionization energy etc., but I was wondering how we could tell if given two very different elements and were asked to compare radii. For example, a element with a small number of electrons but weak effective nuclear charge vs a element ...
by Michelle Fu 1H
Sun Nov 04, 2018 11:50 pm
Forum: Trends in The Periodic Table
Topic: Periodic Trends: Diagonal Relationships
Replies: 3
Views: 278

Re: Periodic Trends: Diagonal Relationships

They are similar because although the element that is further down the group has more electrons it also has a higher effective charge which basically makes it "equal" in electron affinity and ionization energy with the other element which although has less electrons also has a smaller effe...
by Michelle Fu 1H
Sun Nov 04, 2018 5:13 pm
Forum: Trends in The Periodic Table
Topic: Which Ion is larger?
Replies: 2
Views: 67

Which Ion is larger?

Which ion would be bigger, O^- or S^2-? I would've thought that O- is smaller due to it having less electrons but what about S^-2 having more protons, and thus having a larger charge?
by Michelle Fu 1H
Sun Oct 28, 2018 4:58 pm
Forum: Trends in The Periodic Table
Topic: Ex 2.93
Replies: 2
Views: 87

Re: Ex 2.93

I would suggest reviewing the relative sizes of the atoms in accordance to where they are on the periodic table first. Note that this question is also one of the Solution Manual Errors.
by Michelle Fu 1H
Sun Oct 28, 2018 4:32 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Delta X relationship with Delta P
Replies: 3
Views: 138

Re: Delta X relationship with Delta P

Your first point is correct, and your question is valid. The equation tells us more of what it can't be (e.g. an electron can't be found inside the nucleus due to Heisenbergs Uncertainty Equation) rather than what it can, so you are right in your point that the equation on its own doesn't say much a...
by Michelle Fu 1H
Sun Oct 28, 2018 4:19 pm
Forum: *Shrodinger Equation
Topic: Shrodinger equation explanation
Replies: 1
Views: 237

Re: Shrodinger equation explanation

I think that we aren't required to apply the equation just yet (or if ever) because that involves taking second derivatives and so forth. We are just supposed to understand what the implications of Schrodingers equation is (probability of finding a electron) and to interpret graphically the probabil...
by Michelle Fu 1H
Fri Oct 19, 2018 3:39 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Slight Confusion
Replies: 3
Views: 91

Slight Confusion

So I know in lecture Mr. Lavelle went over the axis's such as px, py, pz which he demonstrated with the p orbital. Do these "directions" only apply to p orbitals, or does it also apply to the d orbital too? How would that work?
by Michelle Fu 1H
Fri Oct 19, 2018 3:34 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: 6th Edition 1.43
Replies: 2
Views: 39

Re: 6th Edition 1.43

h, or Plancks constant is 6.63 x 10^(-34), not 1.5457 * 10^-34.
by Michelle Fu 1H
Sun Oct 14, 2018 9:40 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty Principle
Replies: 5
Views: 124

Re: Uncertainty Principle

@Athena I believe (though I may be wrong) it measures the distance between the two outermost possible points where the electron could've ended up on. Your question does bring up other questions though, like is the distance between the two electrons roughly equal all the time? Or when actually pluggi...
by Michelle Fu 1H
Fri Oct 12, 2018 3:40 pm
Forum: DeBroglie Equation
Topic: "Wavelength" of everything with mass
Replies: 3
Views: 52

Re: "Wavelength" of everything with mass

@Mina
I understand the equation but I don't understand the interpretation. If every particle exhibits wave like motion then shouldn't diffraction patterns apply too? How does that work?
by Michelle Fu 1H
Fri Oct 12, 2018 12:03 pm
Forum: DeBroglie Equation
Topic: "Wavelength" of everything with mass
Replies: 3
Views: 52

"Wavelength" of everything with mass

I understand that everything with mass has a wavelength, but how does this wavelength manifest itself physically? For example, in todays lecture Dr. Lavelle had a example involving a baseball. How can a baseball have wavelength? Sorry if this is a super elementary question, I'm just having a hard ti...
by Michelle Fu 1H
Wed Oct 03, 2018 5:27 pm
Forum: Empirical & Molecular Formulas
Topic: Confusion on number of moles
Replies: 4
Views: 145

Re: Confusion on number of moles

@Diane- so just to clarify on your answer- it's as if there are two molecules of H that go into a conglomerate of atoms (H2O) therefore as a whole there are always less molecules or moles of H2O?
by Michelle Fu 1H
Wed Oct 03, 2018 12:45 pm
Forum: Empirical & Molecular Formulas
Topic: Confusion on number of moles
Replies: 4
Views: 145

Confusion on number of moles

If there are .0417 mols of CuCl24H2O, and the question asks for how mols of Cl2 there are, why is it twice as many mols? Intuitively I would think that the number of mols of CuCl24H2O and the mols of Cl2 are the same. I'm just having a hard time understanding how more "things" can make up ...
by Michelle Fu 1H
Tue Oct 02, 2018 8:46 pm
Forum: Molarity, Solutions, Dilutions
Topic: Confused about molarity concept
Replies: 4
Views: 161

Confused about molarity concept

In class Dr. Lavelle had a question that went: What volume of a .0380 M KMnO4 is needed to prepare 250 mL of 1.5 x 10^(-3) MKMnO4? While I understand the math and the answer (9.87 x 10^(-3) L or 9.8 mL, I'm wondering how conceptually this works out as we start off with a more concentrated solution w...

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