Search found 59 matches

by Luc Lorain 1L
Sat Mar 16, 2019 2:58 pm
Forum: First Order Reactions
Topic: half life
Replies: 3
Views: 12

Re: half life

The value of the half life is ultimately dependent on the order of the reaction. For first order equations, d[A]= -kdt, in which the reactant is conspicuously absent.

In reality, we just have to accept that it just be like that sometimes.
(Sorry fam, I just need those fat Chemistry community points)
by Luc Lorain 1L
Sat Mar 16, 2019 2:49 pm
Forum: General Rate Laws
Topic: exponential decay
Replies: 2
Views: 10

Re: exponential decay

It all depends on our understanding of half life. Half life, as you know, is the time it takes for 50% of a sample to decay or otherwise react. As we progress through time, the mass/concentration of the sample decreases rapidly, until only a very small amount is left. The decay follows asymptotic be...
by Luc Lorain 1L
Sat Mar 16, 2019 2:38 pm
Forum: *Enzyme Kinetics
Topic: Catalysts
Replies: 7
Views: 47

Re: Catalysts

It is critical to know that a catalyst does not impact the equilibrium constant of a reaction, just the rates at which the forward and reverse rxns proceed to this equilibrium value. The forward rate (k fwd ) and the reverse rate (k') are impacted to the same degree, as the equilibrium constant, k =...
by Luc Lorain 1L
Sat Mar 16, 2019 2:34 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: The melting of snow on a sunny day
Replies: 3
Views: 45

Re: The melting of snow on a sunny day

Just to clarify, how are we able to determine that the value of T(delta)S is greater than that of deltaH, resulting in a negative value? I understand that deltaH= Hfusion of water (=+6.01 kJ/mol) and that both T and delta S are positive... Does the fact that it is a sunny day imply that T is very la...
by Luc Lorain 1L
Sat Mar 16, 2019 2:30 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Cell Work
Replies: 4
Views: 23

Re: Cell Work

Make sure not to get confused with the maximum work available to a thermodynamical system, in which wmax=-q
by Luc Lorain 1L
Sat Mar 16, 2019 2:26 pm
Forum: Balancing Redox Reactions
Topic: balancing water
Replies: 8
Views: 74

Re: balancing water

We just want to simplify the equation, similar to how we cancel out any intermediates in a kinetics reaction.
by Luc Lorain 1L
Sat Mar 02, 2019 4:49 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics vs. Thermodynamics
Replies: 3
Views: 33

Re: Kinetics vs. Thermodynamics

The thermodynamics of a reaction do not predetermine the kinetics of the reaction, and vice versa. Rather, these processes are two descriptors of the progression of a chemical reaction, describing the spontaneity and rate that the reaction possesses, respectively. As an inverse to the diamond exampl...
by Luc Lorain 1L
Sat Mar 02, 2019 4:44 pm
Forum: General Rate Laws
Topic: Point of equilibrium
Replies: 5
Views: 34

Re: Point of equilibrium

As in the progression graph Dr. Lavelle showed in lecture, the concentration of each species will continue to grow or shrink over time until equilibrium has been reached. At this point, the curves should flatten out to what are essentially horizontal lines (rate of change=0).
by Luc Lorain 1L
Sat Mar 02, 2019 4:37 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Order of Cell Diagrams
Replies: 13
Views: 111

Re: Order of Cell Diagrams

I try to think about it in terms of reactants going to products. For the anode (in some cases, like the Zn/Cu cell) the solid electrode is converted into an aqueous cation. The salt bridge then comes next, to link the anode to the cathode. Then, in the cathode region of the cell, aqueous cations bec...
by Luc Lorain 1L
Sat Mar 02, 2019 4:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Does anyone know if test 2 will be curved?
Replies: 15
Views: 175

Re: Does anyone know if test 2 will be curved?

Man, I can only hope. Everyone I know was able to do the first half of the pH problem, but got wrecked trying to get the final answer.
by Luc Lorain 1L
Sat Mar 02, 2019 4:22 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E˚ vs E
Replies: 13
Views: 107

Re: E˚ vs E

Eo is constant for each reaction, since it represents the cell reaction under very specific conditions (the standard state, 1 atm pressure and 25 oC).
E can vary, even within the same cell, as different experimental conditions impact the result of the reaction.
by Luc Lorain 1L
Sat Mar 02, 2019 4:03 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Porous disk of a concentration cell
Replies: 2
Views: 39

Re: Porous disk of a concentration cell

The porous disk will allow ions from both the anode and cathode to diffuse into the opposite subcell, utilizing the charges of the aqueous species involved in the reaction rather than some proxy (as with a salt bridge). This website does a good job of explaining the intricacies of a salt bridge and ...
by Luc Lorain 1L
Tue Feb 26, 2019 11:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Potential Energy Gradient [ENDORSED]
Replies: 1
Views: 29

Potential Energy Gradient [ENDORSED]

Does the anode of a galvanic cell possess more or less potential energy than the cathode? I understand that electrons flow across a gradient from high to low, but how does this relate?
by Luc Lorain 1L
Sun Feb 24, 2019 3:42 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Spontaneity in Cells
Replies: 2
Views: 23

Re: Spontaneity in Cells

We can derive Gibbs free energy (our primary means of calculating the spontaneity of a reaction) through cell potential by using the following formula: \Delta G^{\circ}_{cell}=-nFE^{\circ} If E o is negative, then \Delta G^{\circ}_{cell} will be positive, and therefore non-spontaneous (F is a positi...
by Luc Lorain 1L
Sun Feb 24, 2019 3:22 pm
Forum: Balancing Redox Reactions
Topic: Balancing / Skeletal Equations
Replies: 4
Views: 50

Re: Balancing / Skeletal Equations

We actually get both H 2 O and either H + ?OH - from the set up of the experiment itself. It is important to note that when balancing equations we are trying to use the existing components to accurately explain a reaction; we are never adding substances to an equation in which they would not already...
by Luc Lorain 1L
Sat Feb 23, 2019 10:33 pm
Forum: Balancing Redox Reactions
Topic: Cell Diagram
Replies: 2
Views: 21

Re: Cell Diagram

A solid electrode is always required when conducting an electrochemical reaction, in order to conduct charge into the appropriate reaction compartment. When there are no solids involved in the oxidative or reductive half-reactions, we use a platinum electrode because it is inert and will not typical...
by Luc Lorain 1L
Sat Feb 23, 2019 9:45 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cell Diagram
Replies: 6
Views: 40

Re: Galvanic Cell Diagram

It should be pretty straight forward to reproduce the galvanic cell diagram, and I feel there is a strong chance that Lavelle will either provide one and ask us questions based off of it, or ask us to draw one from given information.
by Luc Lorain 1L
Sat Feb 23, 2019 9:41 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Line versus Comma
Replies: 2
Views: 12

Re: Line versus Comma

It should also be noted that while a single line represents that there is a phase barrier between two species in either the anode or cathode (ex. Cu (s) and Cu (aq) ), the double line indicates the salt bridge that is in contact between the anode and cathode. The exact composition of...
by Luc Lorain 1L
Sat Feb 23, 2019 9:34 pm
Forum: Balancing Redox Reactions
Topic: Oxidating/Reducing AGENTS
Replies: 6
Views: 40

Re: Oxidating/Reducing AGENTS

Like stated above, pretty much think in terms of opposites. In the oxidation half-reaction, the unique species on the left side of the equation will be the reducing agent (it is being oxidized, losing electrons), while in the reduction half-reaction, the unique species on the left will be the oxidiz...
by Luc Lorain 1L
Wed Feb 13, 2019 2:28 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy at 0 K
Replies: 4
Views: 58

Re: Entropy at 0 K

Molecules that are perfectly ordered have no entropy at 0K (ex. CH4). For molecules that are not perfectly ordered, there is positional/residual entropy at 0K. Expanding on this, molecules that possess residual energy maintain some sort of entropy through positional, rather than kinetic or thermal-...
by Luc Lorain 1L
Wed Feb 13, 2019 2:15 am
Forum: Phase Changes & Related Calculations
Topic: Steam vs Boiling Water
Replies: 8
Views: 84

Re: Steam vs Boiling Water

As we boil water, it remains at a constant temperature (100 degrees C) until all liquid water has completed its phase change to gas. However, although Temperature remains constant, we continue to increase heat in the system throughout the entire process. Therefore, all steam produced through boiling...
by Luc Lorain 1L
Wed Feb 13, 2019 1:44 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Enthalpy and Enthalpy of Formation
Replies: 1
Views: 20

Re: Standard Enthalpy and Enthalpy of Formation

In short, yes. The standard (molar) enthalpy of formation, \Delta H f o , is defined as the change in enthalpy as we form one mol of a substance in its standard state from elements in their standard state. (Aside: standard state just means that the element is without impurities and at 1 atm of press...
by Luc Lorain 1L
Wed Feb 13, 2019 1:30 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Increasing/Decreasing temp
Replies: 8
Views: 66

Re: Increasing/Decreasing temp

The effect of temperature on a given equilibrium will depend on whether the reaction is endothermic or exothermic. Within a reaction, think of heat like a reactant if the equation is endothermic ( \Delta H > 0), and as a product if exothermic ( \Delta H < 0). Though heat is not a discrete substance,...
by Luc Lorain 1L
Mon Jan 21, 2019 4:42 pm
Forum: Ideal Gases
Topic: 5% rule
Replies: 12
Views: 173

Re: 5% rule

As a rule, Dr. Lavelle states that it is generally safe to use the 5% rule when the equilibrium constant <= 10 -3 . For most reaction scenarios, this number is so small that it will lead to a final value of x that does not affect the concentration or partial pressure of an equilibrium species in a n...
by Luc Lorain 1L
Mon Jan 21, 2019 4:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Strong and Weak Acids
Replies: 3
Views: 43

Re: Strong and Weak Acids

Remember that the pH scale is logarithmic and starts at 0, with the pH getting more acidic the closer to 0 one gets from 7 and more basic the farther from 7 one goes in the opposite direction. A weak acid will not dissociate as willingly as a strong acid (which are often very ionic in composition, s...
by Luc Lorain 1L
Mon Jan 21, 2019 4:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Conjugates
Replies: 2
Views: 36

Re: Conjugates

Typically it is very easy to tell the conjugate acid or base for a given species. For a Bronsted-Lowry acid, a conjugate base will simply be that same species with one less H atom on the other side of the reaction. For a Bronsted-Lowry base, a conjugate acid will be the species with one or more H at...
by Luc Lorain 1L
Mon Jan 21, 2019 4:07 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle on Temperature
Replies: 4
Views: 61

Re: Le Chatelier's Principle on Temperature

Though it is not technically correct scientific notation, you can think about heat like its own species in an equilibrium equation. If a reaction is endothermic, ( H>0), think of heat as a reactant, and when exothermic ( H<0), consider heat a product. This makes the application of Le Chatelier's Pri...
by Luc Lorain 1L
Mon Jan 21, 2019 3:57 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp vs Kc
Replies: 7
Views: 60

Re: Kp vs Kc

Like the poster above noted, the equilibrium constant for the concentration of species in gaseous equilibrium and their partial pressures may be the same value, but this often not the case. Partial pressure and concentration within a system are directly proportional in value, meaning that while prop...
by Luc Lorain 1L
Mon Jan 21, 2019 2:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pKa confusion
Replies: 2
Views: 40

Re: pKa confusion

Strong acids (and bases) are assumed to dissociate almost completely in water, thus you can expect H 3 O + formation to be strongly favored at equilibrium. As such, the product concentration in the equilibrium concentration formula should be expected to be much higher than the concentration of react...
by Luc Lorain 1L
Sun Jan 13, 2019 6:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: solids in calculating equilibrium constant? [ENDORSED]
Replies: 8
Views: 76

Re: solids in calculating equilibrium constant? [ENDORSED]

only aq and g solutions are included in the equation (and g is in partial pressure) It should also be expanded that when reactions are completed in a fixed volume container, the addition of noble (inert) gases does not affect equilibrium for similar reasons as pure solids and liquids: they do not a...
by Luc Lorain 1L
Sun Jan 13, 2019 6:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: solids and liquids [ENDORSED]
Replies: 4
Views: 36

Re: solids and liquids [ENDORSED]

The nature of pure solids and liquids further can be extended to pure, inert gases (group VIII). Inert gas can be added to an equilibrium mixture at a constant volume to increase the pressure of the mixture; however there will be no change in equilibrium as the amount of neither reactant nor product...
by Luc Lorain 1L
Sun Jan 13, 2019 6:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: converting between partial pressure and concentration
Replies: 2
Views: 22

Re: converting between partial pressure and concentration

Like the post above states, we do have to use the equation of the ideal gas law, PV=nRT, where P=pressure in atm, V=volume in L, n=moles of substance, R=ideal gas constant, and T=temperature in Kelvin. In order to convert between partial pressure (P) and concentration (M), we need to manipulate this...
by Luc Lorain 1L
Mon Dec 03, 2018 12:29 am
Forum: Lewis Structures
Topic: Octet Rule
Replies: 5
Views: 67

Re: Octet Rule

Certain elements do not need to fill their octet --namely Hydrogen (which can only ever form one bond) He, Li, and Be, which contain only 1s and *some in the last two* 2s orbitals. Other than H, these elements are pretty rare to find in covalent compounds, which may lead to unfamiliarity with this t...
by Luc Lorain 1L
Mon Dec 03, 2018 12:22 am
Forum: Sigma & Pi Bonds
Topic: Pi bonds
Replies: 4
Views: 94

Re: Pi bonds

Since pi bonds connect laterally, rotating them will cause the bonds connecting the molecule to snap as they can't handle the stress of rotational forces. Entire molecules with pi bonds can rotate so long as the atoms connected by pi bonds do not rotate ion opposite directions.
by Luc Lorain 1L
Mon Dec 03, 2018 12:19 am
Forum: Coordinate Covalent Bonds
Topic: Identifying Polydentates
Replies: 4
Views: 56

Re: Identifying Polydentates

Polydentate ligands can be identified be pretty highly inferred by the availability of sites that can form coordinate covalent bonds and their proximity to each other. Regions with many electron pairs (such as amine groups) within an atom are very good at becoming ligands, so molecules with many of ...
by Luc Lorain 1L
Sun Nov 25, 2018 11:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sigma and Pi Bonds
Replies: 2
Views: 31

Re: Sigma and Pi Bonds

It can help to use the example of a figure skater to imagine this concept. When the figure skater is balanced on one foot, they can rotate in only one direction, resulting in smooth rotation-- this would be analogous to the range of motion of a sigma bond. When the figure skater places both feet on ...
by Luc Lorain 1L
Sun Nov 25, 2018 11:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Shape
Replies: 3
Views: 38

Re: Trigonal Shape

Trigonal planar exists in one plane, and you think of this shape as flat with 3 electron density regions. Trigonal pyramidal, on the other hand, is like tetrahedral, where the shape is characterized by 4 electron density regions as far apart from one another as possible in a 3D aspect. Trigonal pla...
by Luc Lorain 1L
Sun Nov 25, 2018 11:15 pm
Forum: Hybridization
Topic: regions of electron density and double bonds
Replies: 2
Views: 33

Re: regions of electron density and double bonds

This concept makes a fair amount of sense if we consider how electron distribution and molecular stability correlate to each other. The closer two bonds connecting two atoms in a molecule are, the more concentrated the strength of the bonds are (providing the most stable arrangement for the molecule...
by Luc Lorain 1L
Sun Nov 18, 2018 11:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole moments
Replies: 8
Views: 69

Re: Dipole moments

Dipole moments cancel each other out when they are equal in charge and opposite in direction. This can happen when a central molecule is surrounded by multiple identical atoms (such as in linear, trigonal planar, tetrahedral, or octahedral molecules like CH 4 and SF 6 ). In these structures, each su...
by Luc Lorain 1L
Sun Nov 18, 2018 11:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity in Molecule
Replies: 3
Views: 43

Re: Polarity in Molecule

In addition to this, an easy way to identify polarity (or its absence) in a Lewis structure is to see whether a single central atom in surrounded by any number of identical surrounding atoms (such as in tetrahedral, trigonal planar, octahedral, etc..). In these, each surrounding atom pulls electrons...
by Luc Lorain 1L
Sun Nov 18, 2018 11:09 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2 Atoms
Replies: 1
Views: 31

Re: 2 Atoms

A two-atom molecule is always linear by the definition of an angle. In order to make an angle one must have 3 points; with a diatomic molecule, only a straight line can connect the two atoms. Because these structures of molecules are fixed in shape, they are generally excluded from the VSEPR system.
by Luc Lorain 1L
Sun Nov 11, 2018 10:20 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 9
Views: 181

Re: Formal Charge

For Lewis structures with equivalent resonance structures, I did the calculations for one of the structures, and put the appropriate formal charges around the other resonance forms. Otherwise, yeah you should do independent calculations for each resonance form.
by Luc Lorain 1L
Sun Nov 11, 2018 10:13 pm
Forum: Bond Lengths & Energies
Topic: Drawing resonance structures?
Replies: 6
Views: 68

Re: Drawing resonance structures?

I think that if there is a single compound with multiple resonance structures that are equally stable (example, the different resonance structures of benzene, C 6 H 6 ), you should draw all possible Lewis structures with the arrow notation in between. If there is a single most stable Lewis structure...
by Luc Lorain 1L
Sun Nov 11, 2018 10:04 pm
Forum: Octet Exceptions
Topic: learning octet excptions
Replies: 4
Views: 52

Re: learning octet excptions

An additional subgroup of octet exceptions are the Lewis acids of periods 2 and 3-- Boron and Aluminum. These two elements are alright having a partially-filled octet of 6 valence e - , but may also possess a filled octet. I think you may just need to remember that those two are exceptions; perhaps ...
by Luc Lorain 1L
Sun Nov 04, 2018 10:46 pm
Forum: Trends in The Periodic Table
Topic: Atomic Radius
Replies: 6
Views: 112

Re: Atomic Radius

The reason why atomic radius increases down a group can further be explained with electron shielding: as each new shell is added to an atom (due to other shells being filled w/ electrons), shells closer to the nucleus will "shield" electrons in higher energy shells from the effective nucle...
by Luc Lorain 1L
Sun Nov 04, 2018 10:41 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 2
Views: 56

Re: Electron Affinity

The Noble gasses are nonreactive. Neon has a greater effective charge, but its octet is complete, so it won't pick up any electrons, where chlorine will in order to complete the octet. Basically this; Chlorine is reactive due to its noncomplete (7/8 e-) valence shell, which pulls electrons in to co...
by Luc Lorain 1L
Sun Nov 04, 2018 10:40 pm
Forum: Trends in The Periodic Table
Topic: 6th Edition 2.71
Replies: 4
Views: 56

Re: 6th Edition 2.71

In short, diagonal trends exist because the trends of the periodic table cancel each other out if you go down and to the right. As one goes down a group, atomic radius increases, electron affinity decreases, and ionization energy decreases. As one goes right across a period the opposite happens: ato...
by Luc Lorain 1L
Sun Oct 28, 2018 6:06 pm
Forum: Lewis Structures
Topic: Ground State e- Configuration
Replies: 3
Views: 44

Re: Ground State e- Configuration

You should be able to answer your question after memorizing the number of electrons that each subshell can hold. These numbers are fixed no matter how many shells there are in an atom, and (except for in certain special cases that Dr. Lavelle has singled out) tend to be filled completely before elec...
by Luc Lorain 1L
Sun Oct 28, 2018 5:53 pm
Forum: Trends in The Periodic Table
Topic: Homework 2.59
Replies: 3
Views: 83

Re: Homework 2.59

The presence of exponents signifies that the atoms provided are not in their ground state but rather in ionic form. If we reflect on what Dr. Lavelle said in his lecture on Wednesday, ionic radius should increase as we go down a group. This is because each additional shell shields some electrons fro...
by Luc Lorain 1L
Sun Oct 28, 2018 5:46 pm
Forum: Trends in The Periodic Table
Topic: Removing 2nd e- [ENDORSED]
Replies: 4
Views: 52

Re: Removing 2nd e- [ENDORSED]

In certain cases, such as the alkali metals in Group 1A, this idea is very easily imagined. Since these metals all have only 1 valence electron in their ground state, it should be fairly easy (low energy requirement) to remove that one electron. However, after this electron is lost the atom is left ...
by Luc Lorain 1L
Sun Oct 21, 2018 10:29 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: h with a line through it?
Replies: 8
Views: 125

Re: h with a line through it?

It just represents another one of those symbols that physicists created to make their lives easier while writing calculations. Its a similar concept to the Hamiltonian, which represents a long expression related to wave-particle duality with the letter H.
by Luc Lorain 1L
Sun Oct 21, 2018 9:51 pm
Forum: Photoelectric Effect
Topic: Question from Post-Assessment Module
Replies: 2
Views: 36

Re: Question from Post-Assessment Module

The work function is defined as the minimum amount of energy (often given in electrovolts) required to remove an electron from the metal. It can also be referred to as the threshold energy for removal.
by Luc Lorain 1L
Sun Oct 21, 2018 9:40 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: What is a nodal plane?
Replies: 5
Views: 98

Re: What is a nodal plane?

Just add some extra info (got to get those Chem Comm points!) This has to do with the shape of each orbital shell. Since the s-orbital is spherical, it does not have any risk of going through the actual nucleus of the atom, where the Heisenberg uncertainty principle tells us there is almost no chanc...
by Luc Lorain 1L
Sun Oct 14, 2018 8:48 pm
Forum: Properties of Electrons
Topic: Rydberg constant
Replies: 7
Views: 124

Re: Rydberg constant

Rydberg constant has been only really been shown to be used in context of the Rydberg equation in this chapter thus far. Like the poster above has stated, it is used to calculate the energy released from electrons in a hydrogen atom while undergoing spectroscopy (NOTE: this equation is specifically ...
by Luc Lorain 1L
Sun Oct 14, 2018 8:13 pm
Forum: Properties of Electrons
Topic: Wave Properties of Electrons
Replies: 2
Views: 45

Re: Wave Properties of Electrons

So basically scientists have been able to create models as to why light behaves the way it does when it is diffracting, and they are dependent on light being organized as a wave. You can see diffraction when white light passes through a prism and splits into a rainbow spectrum on the other side, or ...
by Luc Lorain 1L
Sun Oct 14, 2018 7:48 pm
Forum: Properties of Light
Topic: De Broglie Equation
Replies: 6
Views: 60

Re: De Broglie Equation

Pretty much what is posted above. In addition, we've been working with grams quite a bit because molecular weights are typically given in the units grams per mole, allowing for quick stoichiometric conversions.
by Luc Lorain 1L
Sat Oct 06, 2018 5:06 pm
Forum: Balancing Chemical Reactions
Topic: Combustion Question on Modules
Replies: 3
Views: 40

Re: Combustion Question on Modules

I think the formulas for the hydrocarbons will be provided, but we need to know that when a question says combustion/oxidation/burning it will have a hydrocarbon + O2 --> CO2 + H2O. Yeah, this is pretty standard terminology for questions. Lavelle touched upon this in his first few lectures, that co...
by Luc Lorain 1L
Sat Oct 06, 2018 4:53 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Moles [ENDORSED]
Replies: 6
Views: 209

Re: Moles [ENDORSED]

For this problem it is important to look at both the subscripts and balancing coefficients involved with the products and reactants. I think that its possible that you just overlooked the subscript 2 on Fe 2 O 3 , but if not I can explain in more detail. Since a mole is a numerical quantity (like 5,...
by Luc Lorain 1L
Fri Oct 05, 2018 2:25 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Question regarding Roman Numerals
Replies: 3
Views: 57

Re: Question regarding Roman Numerals

Hello! The poster above did a great job of explaining the reason for roman numerals being listed beside tin in your problem. This notation is now commonly used for some metals not found within groups 1 and 2 on the periodic table. For these metals, like the previous poster stated, it is possible for...

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