Search found 101 matches
- Sat Mar 14, 2020 4:16 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: determining a catalyst
- Replies: 5
- Views: 77
Re: determining a catalyst
A catalyst is used up and formed or stays intact throughout the reaction.
- Sat Mar 14, 2020 4:15 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Temperature and Kinetics
- Replies: 3
- Views: 54
Re: Temperature and Kinetics
More molecules have enough kinetic energy, so more collisions happen.
- Sat Mar 14, 2020 4:14 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Catalysts
- Replies: 5
- Views: 78
Re: Catalysts
A catalyst is used up and formed and an intermediate is formed and used up.
- Sat Mar 14, 2020 4:13 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Arrhenius Equation "A"
- Replies: 3
- Views: 56
Re: Arrhenius Equation "A"
Does it change with temperature though?
- Sat Mar 14, 2020 4:13 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Catalysts
- Replies: 8
- Views: 102
Re: Catalysts
Homogenous catalysts are used up and formed, but heterogeneous is not since the reactants and catalysts are in different states.
- Sat Mar 07, 2020 7:32 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: K=kforward/kreverse
- Replies: 1
- Views: 84
K=kforward/kreverse
Can someone derive this equation for me? Why does K=kforward/kreverse?
- Sat Mar 07, 2020 7:31 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: intermediates
- Replies: 4
- Views: 144
Re: intermediates
They are not part of the overall rate law but the elementary steps.
- Sat Mar 07, 2020 7:17 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Change in Equilibrium Constant
- Replies: 2
- Views: 351
Re: Change in Equilibrium Constant
I believe pressure changes could also induce temperature changes, which indirectly changes K.
- Sat Mar 07, 2020 7:15 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Proposing Reaction Mechanisms
- Replies: 3
- Views: 78
Re: Proposing Reaction Mechanisms
I think Dr.Lavelle said we need to explain the mechanisms from its rate of formation but not propose one.
- Sat Mar 07, 2020 7:11 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: 7C.7
- Replies: 3
- Views: 87
Re: 7C.7
The rate law of formation depends on the slowest reaction, in this case, the first reaction.
- Sun Mar 01, 2020 5:36 pm
- Forum: General Rate Laws
- Topic: HW 9 question 7A.3
- Replies: 2
- Views: 90
Re: HW 9 question 7A.3
For this question, you are just finding the rate of formation for the listed substance, which is the coefficient times the unique rate.
- Sun Mar 01, 2020 5:31 pm
- Forum: General Rate Laws
- Topic: Unique Rate
- Replies: 3
- Views: 89
Re: Unique Rate
Remember to add a negative sign of the part of the reactant as we always want positive value for rates.
- Sun Mar 01, 2020 5:31 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: units of T
- Replies: 11
- Views: 535
Re: units of T
Always use the standard unit if not specified by the problem.
- Sun Mar 01, 2020 5:30 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Units and order
- Replies: 3
- Views: 323
Re: Units and order
I don't remember Dr.Lavelle saying anything about using units to determine the order, but this seems like a pretty useful approach.
- Sun Mar 01, 2020 5:26 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: determine n
- Replies: 16
- Views: 662
Re: determine n
It's essentially the order of the reaction that is determined by the concentration of reactants.
- Sat Feb 22, 2020 4:00 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Problem 6L.3-b
- Replies: 1
- Views: 57
Re: Problem 6L.3-b
In this reaction, the C and Pt are electrodes that help transfer the electrons but not directly participate in the reaction. It is given by the table as they stay neutral the entire reaction.
- Sat Feb 22, 2020 3:56 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: E cell
- Replies: 3
- Views: 83
Re: E cell
Should it be lnK or lnQ when it reaches equilibrium or the two have the same value.
- Sat Feb 22, 2020 3:52 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: How to find n in ΔG°= -nFE°
- Replies: 2
- Views: 99
Re: How to find n in ΔG°= -nFE°
In this question, E is given and F is a constant. The only thing you need to find is n, which is the electron transferred. By breaking down the reaction into two half-reaction, you will know the number of electrons transferred by the change in its charges.
- Sat Feb 22, 2020 3:49 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Reversing Potentials
- Replies: 2
- Views: 45
Re: Reversing Potentials
Honestly, it would not matter. If your E is negative, you simply reverse it and the position of reactants and products.
- Sat Feb 22, 2020 3:47 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n in -nFE
- Replies: 12
- Views: 182
Re: n in -nFE
Be aware that since an equation is composed of two half reaction. You only need to know the moles of electron transferred in one group but not adding up that of both reactions.
- Sat Feb 22, 2020 3:39 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: E cell
- Replies: 3
- Views: 83
E cell
Will Ecell stays the same as the reactions go on or the value goes to 0 as it becomes equilibrium?
- Sun Feb 16, 2020 3:06 am
- Forum: Van't Hoff Equation
- Topic: Equilibrium
- Replies: 6
- Views: 409
Re: Equilibrium
Since K means the equlibirum ration of product over reactant. We use the equation to calculate K.
- Sun Feb 16, 2020 3:05 am
- Forum: Van't Hoff Equation
- Topic: van't hoff
- Replies: 2
- Views: 343
Re: van't hoff
You use both these equations
∆G° = - RT ln K
∆G° = ∆H° - T∆S°
and derive the van't hoff equation form balancing both side.
∆G° = - RT ln K
∆G° = ∆H° - T∆S°
and derive the van't hoff equation form balancing both side.
- Sun Feb 16, 2020 3:03 am
- Forum: Van't Hoff Equation
- Topic: What is this? [ENDORSED]
- Replies: 7
- Views: 167
Re: What is this? [ENDORSED]
It is used to calculate K when delta H and S are known.
- Sun Feb 16, 2020 3:02 am
- Forum: Van't Hoff Equation
- Topic: Delta H and S naught
- Replies: 2
- Views: 51
Delta H and S naught
Can someone explain to me why we use Delta H naught and S naught for Van't Hoff Equation even though there is a temperature change? Doesn't naught mean standard condition? Thanks in advance,
- Sun Feb 16, 2020 2:59 am
- Forum: Van't Hoff Equation
- Topic: Van Hoff's Constants
- Replies: 6
- Views: 92
Re: Van Hoff's Constants
On the lecture slides, it says both delta H and delta S are constants.
- Sun Feb 09, 2020 11:48 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs Free Energy
- Replies: 5
- Views: 64
Re: Gibbs Free Energy
It would be easier if you draw out the graph and compare the value of it. The graph is shown in 4J.4 in the textbook.
- Sun Feb 09, 2020 11:47 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Thermodynamically stable/unstable
- Replies: 2
- Views: 56
Re: Thermodynamically stable/unstable
It will decompose but not all reaction is rapid, the rapid ones are called labile.
- Sun Feb 09, 2020 11:45 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: ∆S for summation
- Replies: 3
- Views: 44
Re: ∆S for summation
Are you sure that is what Dr. Levelle said? To my understanding, you can still calculate for G using deltaG=-Tdelta Stotal, which left out enthalpy but not entropy.
- Sun Feb 09, 2020 11:43 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 4J.5 Part c
- Replies: 2
- Views: 54
Re: 4J.5 Part c
The state of the substance is determined by its most stable phase. For carbon, it is solid
- Sun Feb 09, 2020 11:40 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: U=3/2 nRT
- Replies: 4
- Views: 49
U=3/2 nRT
Can someone explain the idea of the equation U=3/2 nRT and how it is used?
- Sun Feb 02, 2020 1:32 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated System
- Replies: 4
- Views: 62
Isolated System
For an isolated system will all values of deltaU=q+w equal 0 or is it just the deltaU that is 0?
- Sun Feb 02, 2020 1:23 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: 4b.3b
- Replies: 3
- Views: 52
Re: 4b.3b
but why is the answer not 490J but 9000J?
- Sun Feb 02, 2020 1:22 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Closed system
- Replies: 5
- Views: 110
Closed system
Can someone explain why the volume of a closed system can change? Any examples would help!
- Sun Feb 02, 2020 1:19 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: 4A.3 part c
- Replies: 4
- Views: 75
Re: 4A.3 part c
Mine says 8 as well, but it is not the latest edition, so 28 should be the right answer.
- Sun Feb 02, 2020 1:18 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Textbook problem help
- Replies: 2
- Views: 84
Re: Textbook problem help
For this type of question, do we assume the condition is constant pressure or is there any hint in the question?
- Sun Jan 26, 2020 12:41 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam v. liquid
- Replies: 7
- Views: 84
Re: Steam v. liquid
Yes, because steam contains more heat that is absorbed during the phase change. So it releases the heat when condensing on our skin.
- Sun Jan 26, 2020 12:28 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase changes: endothermic vs exothermic
- Replies: 12
- Views: 223
Re: Phase changes: endothermic vs exothermic
Yes, the opposite of these process is condensation, freezing, and deposition respectively, which are all exothermic.
- Sun Jan 26, 2020 12:23 pm
- Forum: Phase Changes & Related Calculations
- Topic: Standard Enthalpy of Formation
- Replies: 2
- Views: 22
Re: Standard Enthalpy of Formation
Since it is the most stable form of an element being turned into the most stable form, it is essentially the same substance on both sides of the reaction. The energy change is therefore 0.
- Sun Jan 26, 2020 12:21 pm
- Forum: Phase Changes & Related Calculations
- Topic: State Property
- Replies: 6
- Views: 110
Re: State Property
Heat is just like work, it is pathway-dependent, so you must take into account how much heat goes in and out of the system. Enthalpy, on the other hand only accounts for the initial and final stage of the reaction.
- Sun Jan 26, 2020 12:19 pm
- Forum: Phase Changes & Related Calculations
- Topic: Standard State
- Replies: 3
- Views: 27
Re: Standard State
It's both 1 atm for gas and solution, but solution has to be 1M as well.
- Sun Jan 19, 2020 10:48 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs Kc
- Replies: 3
- Views: 28
K vs Kc
How is K different from Kc? In the textbook, it listed out both K and Kc values and I'm wondering which one I should use for calculation.
- Sun Jan 19, 2020 10:42 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: % protonated
- Replies: 3
- Views: 25
Re: % protonated
Since being protonated is accepting H+, we know that it will appear on the right side of the equation as being the protonated product of the reactant.
- Sun Jan 19, 2020 10:40 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ka and Kb
- Replies: 3
- Views: 13
Re: Ka and Kb
You could use these two interchangeably since Ka * Kb = Kw, it's just a matter of conversion and what you're looking for.
- Sun Jan 19, 2020 10:38 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: pKa versus pH
- Replies: 3
- Views: 47
Re: pKa versus pH
For the second question where you mention determining whether it's acid or base by looking at pH<pKa and pH>pKa or pKb, is that mentioned in class? I don't remember Lavelle saying that.
- Sun Jan 19, 2020 10:31 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Acid and Base Concentration
- Replies: 3
- Views: 60
Re: Acid and Base Concentration
You can only determine the pH with the acid and base concentration. determining whether the acid is strong or weak, you have to analyze its formula or even draw out its structure.
- Sun Jan 12, 2020 12:07 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Partial pressure
- Replies: 4
- Views: 45
Re: Partial pressure
Total pressure is the sum of all gas's partial pressure. Since we only have to solve for the gas used in the reaction, we use the partial pressure instead.
- Sun Jan 12, 2020 12:05 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Week 1 lecture note
- Replies: 4
- Views: 95
Re: Week 1 lecture note
Thanks! These notes are really helpful! I wonder if we have access to Lavelle's slides by any means.
- Sun Jan 12, 2020 12:02 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G.1.C explanation (SSM)
- Replies: 2
- Views: 31
Re: 5G.1.C explanation (SSM)
The equilibrium constants do not change as long as the temperature stays the same.
- Sun Jan 12, 2020 11:59 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Where Equilibrium "sits"
- Replies: 2
- Views: 42
Re: Where Equilibrium "sits"
Pressure changes that cause volume change can also affect where the equilibrium sits since the concentration is different.
- Sun Jan 12, 2020 11:57 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Q<K
- Replies: 4
- Views: 50
Re: Q<K
The reaction sits to the right when Q<K since there are more reactants than the products. To achieve an equilibrium state, more products are formed.
- Sun Dec 08, 2019 3:41 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate
- Replies: 3
- Views: 146
Re: Polydentate
you could also measure the formal charge of the site with lone pairs.
- Sun Dec 08, 2019 3:39 pm
- Forum: Biological Examples
- Topic: chelating ligands
- Replies: 3
- Views: 107
Re: chelating ligands
Chelating is basically any polydentate ligand, and denticity is number of bonding sites.
- Sun Dec 08, 2019 3:38 pm
- Forum: Naming
- Topic: bis- tris- tetrakis-
- Replies: 8
- Views: 273
Re: bis- tris- tetrakis-
for polydentate, you have to add those prefix in front of the ligands.
- Sun Dec 08, 2019 3:36 pm
- Forum: Biological Examples
- Topic: Formulas for acid rain
- Replies: 2
- Views: 117
Re: Formulas for acid rain
NO2 + H2O --> H2NO3, SO3 + H2O --> H2SO4
- Sun Dec 01, 2019 2:42 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis Acids & Bases vs Bronsted Acids & Bases
- Replies: 2
- Views: 51
Re: Lewis Acids & Bases vs Bronsted Acids & Bases
I recommend you read this
https://chem.libretexts.org/Courses/Mou ... _and_Bases
https://chem.libretexts.org/Courses/Mou ... _and_Bases
- Sun Dec 01, 2019 2:31 pm
- Forum: Lewis Acids & Bases
- Topic: transition metal is acid?
- Replies: 2
- Views: 43
transition metal is acid?
Are transition metal cations acidic since they accept electrons from ligands?
- Sun Dec 01, 2019 2:29 pm
- Forum: Lewis Acids & Bases
- Topic: Define Acid and Base
- Replies: 7
- Views: 129
Define Acid and Base
Can someone define acid and base? Is the compound only considered acid and base when dissolved? For example, is SO4 acidic since it forms H2SO4 in the water?
- Sun Dec 01, 2019 2:25 pm
- Forum: Naming
- Topic: Names of ligands
- Replies: 4
- Views: 54
Names of ligands
Are we supposed to memorize the names of the ligands or the general rule naming rules of the coordinate compound instead?
- Sun Dec 01, 2019 2:23 pm
- Forum: Naming
- Topic: Water in Coordination Compounds
- Replies: 7
- Views: 149
Re: Water in Coordination Compounds
The atom that is linked to the metal atom is often written first to emphasize the bonding sites. You could also underline the bonding atom to indicate.
- Sun Nov 24, 2019 3:39 pm
- Forum: Coordinate Covalent Bonds
- Topic: Covalent character: BeCl2 Vs MgCl2
- Replies: 4
- Views: 1544
Re: Covalent character: BeCl2 Vs MgCl2
Smaller cations should have more polarizability because it exerts a stronger attraction force to nearby electrons.
- Sun Nov 24, 2019 3:28 pm
- Forum: Coordinate Covalent Bonds
- Topic: Myoglobin
- Replies: 6
- Views: 589
Re: Myoglobin
Since each myoglobin binds to one O2. 4 myoglobin, which is hemoglobin, should bind to 4 O2.
- Sun Nov 24, 2019 3:26 pm
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate Covalent Bond
- Replies: 2
- Views: 145
Re: Coordinate Covalent Bond
I think the term Lewis acid or base only describes the atom or molecule that gives or receives the electrons. So even metal cations are considered lewis acid.
- Sun Nov 24, 2019 3:24 pm
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate Covalent Bonds
- Replies: 5
- Views: 263
Re: Coordinate Covalent Bonds
The ability to form coordinate covalent bonds allows the molecule to form a complex structure, thus the shape of the compound makes it biologically significant.
- Sun Nov 24, 2019 3:21 pm
- Forum: Coordinate Covalent Bonds
- Topic: Ligandsc-Chelate
- Replies: 1
- Views: 131
Ligandsc-Chelate
Can someone explain to me why tetradentate is less common than the others?
- Sun Nov 17, 2019 11:17 am
- Forum: Ionic & Covalent Bonds
- Topic: HW #2.25
- Replies: 2
- Views: 69
Re: HW #2.25
Both size and electronegativity affect the result, but since the size of atom follows the same trend as that of electronegativity, PF should have longer bonds.
- Sun Nov 17, 2019 11:13 am
- Forum: Dipole Moments
- Topic: 3F15
- Replies: 2
- Views: 90
Re: 3F15
For both molecules, the electronegative force cancels out, but since AsF5 has more electrons, it has a higher boiling point.
- Sun Nov 17, 2019 11:10 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: polarizability/polar power and bonds
- Replies: 2
- Views: 125
Re: polarizability/polar power and bonds
Polarizing power is the tendency of ions to cause large distortion, cations that are small have higher polarizing power, and anions that are larger are more "polarizable". Polarizability follows the trend of electronegativity and it applies to covalent compounds.
- Sun Nov 17, 2019 11:03 am
- Forum: Ionic & Covalent Bonds
- Topic: Bonds strength
- Replies: 4
- Views: 73
Bonds strength
Can someone explain to me why double bond is just slightly stronger than single bond? Why does not the strength between the two atoms double?
- Sun Nov 17, 2019 11:01 am
- Forum: Bond Lengths & Energies
- Topic: Strongest Bonds
- Replies: 11
- Views: 436
Re: Strongest Bonds
A covalent bond is stronger than ionic bond because ionic bonds dissolve in water
- Sun Nov 10, 2019 12:40 pm
- Forum: Dipole Moments
- Topic: BOND STRENGTH
- Replies: 4
- Views: 44
Re: BOND STRENGTH
The number of bonds have nothing to do with electronegativity. Electronegativity is defined as the tendency to attract electrons in a covalent compound.
- Sun Nov 10, 2019 12:38 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Interaction Potential Energy
- Replies: 2
- Views: 40
Re: Interaction Potential Energy
Increasing sizes or molar mass results in stronger attractive interactions. Stronger attractive interactions have lower interaction potential energy since the equation of interaction potential energy has a negative sign.
- Sun Nov 10, 2019 12:31 pm
- Forum: Dipole Moments
- Topic: Ionic vs Covalent Solubility
- Replies: 3
- Views: 39
Re: Ionic vs Covalent Solubility
For covalent compounds, it really depends on how polarized the substance is. Polar covalent compounds also dissolve in water.
- Sun Nov 10, 2019 12:27 pm
- Forum: Bond Lengths & Energies
- Topic: Interaction Potential Energy Formula
- Replies: 2
- Views: 48
Re: Interaction Potential Energy Formula
All you need to know is the relationship between the different variables. There is no calculation on the test.
- Sun Nov 10, 2019 12:26 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Interaction potential energy equation
- Replies: 2
- Views: 48
Interaction potential energy equation
Can someone explain the equation -(alpha1 alpha2)/(r^6) to me? What does the negative sign have to do with attraction force?
- Sat Nov 02, 2019 4:06 pm
- Forum: Ionic & Covalent Bonds
- Topic: Electronegativity difference >1.5 but <2
- Replies: 3
- Views: 62
Electronegativity difference >1.5 but <2
Molecules with electronegativity difference >1.5 but <2 are considered ionic or covalent?
- Sat Nov 02, 2019 4:04 pm
- Forum: Dipole Moments
- Topic: London Dispersion vs Van der waals
- Replies: 2
- Views: 46
Re: London Dispersion vs Van der waals
Dispersion, induced dipole induced dipole, London, and Van der waals all mean the same thing.
- Sat Nov 02, 2019 4:02 pm
- Forum: Resonance Structures
- Topic: Delocalization
- Replies: 4
- Views: 59
Re: Delocalization
atoms with the lowest ionization go in the middle with the exception of H. H is never central!
- Sat Nov 02, 2019 3:59 pm
- Forum: Octet Exceptions
- Topic: expanded octet for P
- Replies: 2
- Views: 58
expanded octet for P
Can somebody explain to me why the additional electron added to phosphorous goes into the 3d orbitals instead of 4s? Doesn't 4s orbital have lower energy until both 3d and 4s are occupied?
- Sat Nov 02, 2019 3:56 pm
- Forum: Resonance Structures
- Topic: Visual structure of resonance structure
- Replies: 3
- Views: 59
Visual structure of resonance structure
Hey, can somebody explain how resonance structure look like visually? How can an electron be divided or separated into different multiple bonds or is resonance structure just conceptually viable?
- Sat Oct 26, 2019 2:16 pm
- Forum: Octet Exceptions
- Topic: Max number of valence e
- Replies: 6
- Views: 98
Re: Max number of valence e
I think the term valence electron is the # of electrons in the outermost shell (at the molecule's ground state). So it should be less than 8.
- Sat Oct 26, 2019 2:14 pm
- Forum: Resonance Structures
- Topic: Delocalized electrons
- Replies: 2
- Views: 81
Re: Delocalized electrons
I think delocalized electrons occur not because of similar electronegativity but a molecule having more than one acceptable lewis structures.
- Sat Oct 26, 2019 2:12 pm
- Forum: Lewis Structures
- Topic: Expanded octets
- Replies: 2
- Views: 45
Re: Expanded octets
Any atoms that have orbitals higher than 3S can break the octet rule.
- Sat Oct 26, 2019 2:09 pm
- Forum: Ionic & Covalent Bonds
- Topic: Electronegativity and electron affinity
- Replies: 3
- Views: 40
Electronegativity and electron affinity
Can someone explain the difference between these two terms?
- Tue Oct 22, 2019 2:56 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: HW 1E.5
- Replies: 2
- Views: 49
HW 1E.5
Can someone explain this sentence to me: Electrons in an s-orbital are more effective than those in other orbitals at shielding other electrons from the nuclear charge because an electron in an s-orbital can penetrate to the nucleus of an atom. What does it mean to penetrate to the nucleus of an atom?
- Thu Oct 17, 2019 4:35 pm
- Forum: Properties of Electrons
- Topic: Angstrom Conversion
- Replies: 12
- Views: 190
Re: Angstrom Conversion
Convert anything to meter first before you convert it to another unit. For example, one nanometer is 10^-9 meter, which is 10 Angstrom.
- Thu Oct 17, 2019 4:33 pm
- Forum: Properties of Electrons
- Topic: 1B.3
- Replies: 3
- Views: 78
Re: 1B.3
The answer is the Photoelectric effect. Since one photon interacts with one electron, the only way to knock off the electrons from the metal is to increase the frequency, which subsequently increases the energy per photon. If photon behaves like waves, then you should be able to increase the intensi...
- Thu Oct 17, 2019 4:30 pm
- Forum: DeBroglie Equation
- Topic: Frequency and wavelength
- Replies: 2
- Views: 69
Frequency and wavelength
Can we also find the frequency of the object using the DeBrogile Equation after we find the wavelength?
- Thu Oct 17, 2019 4:28 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Hidden variable
- Replies: 1
- Views: 86
Hidden variable
What does the term "hidden variable" mean in the context of Copenhagen interpretation and how is it different from Heisenberg Indeterminacy equation?
- Thu Oct 17, 2019 3:46 pm
- Forum: Einstein Equation
- Topic: unit of energy
- Replies: 7
- Views: 652
Re: unit of energy
I got tricked by the unit as well... There is one question on the textbook that requires you to convert Kev to Joule before calculation.
- Thu Oct 10, 2019 10:03 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: HW question spectral line
- Replies: 1
- Views: 50
HW question spectral line
17. In an atomic absorption spectrum what does one line (one wavelength) represent? A. It represents the wavelength of light emitted by the gas sample. B. It represents the wavelength of light absorbed by the gas sample. C. It represents the frequency of light emitted by the gas sample. D. None of t...
- Thu Oct 10, 2019 10:01 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Bohr Frequency Condition
- Replies: 1
- Views: 50
Re: Bohr Frequency Condition
Atoms only absorb and release lights with a specific wavelength. The frequency of the light determines how much energy the photons have, so it only emits energy when the light's energy matches ΔE between energy levels. Therefore, light is not continuous and we can only see groups of spectral lines o...
- Thu Oct 10, 2019 9:53 am
- Forum: Properties of Light
- Topic: Partical VS Wave
- Replies: 2
- Views: 140
Re: Partical VS Wave
Increasing the amplitude or intensity of a wave increases the energy that bounces back, but , for light, it doesn't. Instead, you have to increase the frequency of the light. From the equation E=hv, we derived that whenever frequency(v) increases, the energy of the photon(E) also increases.
- Thu Oct 10, 2019 9:50 am
- Forum: Properties of Light
- Topic: Hydrogen Atoms for White Light
- Replies: 3
- Views: 29
Re: Hydrogen Atoms for White Light
I think it has to do with hydrogen having only one electron making it one of the easiest to observe. For molecules, orbits will overlap with each other, creating hybrid orbitals. This makes molecules much harder to observe since you're now dealing with new orbitals created by two or more atoms.
- Thu Oct 10, 2019 9:48 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Decreasing gap between energy level
- Replies: 6
- Views: 129
Decreasing gap between energy level
Why does the gap between different shells decrease as the level goes up?
- Tue Oct 01, 2019 8:50 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: G 25
- Replies: 7
- Views: 129
G 25
"Practitioners of the branch of alternative medicine known as homeopathy claim that very dilute solutions of substances can have an effect. Is the claim plausible? To explore this question, suppose that you prepare a solution of a supposedly active substance, X, with a molarity of 0.10 mol/L. T...
- Tue Oct 01, 2019 2:13 pm
- Forum: Limiting Reactant Calculations
- Topic: Methods of identifying Limiting Reactants
- Replies: 5
- Views: 116
Re: Methods of identifying Limiting Reactants
First, you balance the equation and find out the ratio. Then, you compare the ratio you get from the equation to the mole ratio you actually have. Start from here, it becomes obvious.
- Tue Oct 01, 2019 2:08 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: ions
- Replies: 4
- Views: 485
Re: ions
A cation is positive. Electron is negatively charged. So it loses electrons.
- Tue Oct 01, 2019 2:02 pm
- Forum: Balancing Chemical Reactions
- Topic: Tips for Balancing Chemical Equations [ENDORSED]
- Replies: 14
- Views: 294
Re: Tips for Balancing Chemical Reactions [ENDORSED]
Start with the element that appears the least number of times on both sides. If more than one compound from the same side of the equation have the elements, it would be harder to balance because there will be two coefficient.
- Tue Oct 01, 2019 1:57 pm
- Forum: Empirical & Molecular Formulas
- Topic: Mass Percent Composition
- Replies: 5
- Views: 102
Re: Mass Percent Composition
You only have to imagine there is 100 grams when %composistion is given but not the mass. (the number of grams you used is not fixed, you can use whatever you want as long as you keep the calculation simple and clear, but usually, 100 grams is the most straightforward and simple)