Search found 100 matches
- Sat Mar 14, 2020 8:29 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Reaction order
- Replies: 4
- Views: 348
Re: Reaction order
It can be used with any reaction orded
- Sat Mar 14, 2020 8:24 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2 Return
- Replies: 20
- Views: 1145
Re: Test 2 Return
Pretty sure you can email and ask your TA!
- Sat Mar 14, 2020 1:58 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: heterogeneous catalyst
- Replies: 4
- Views: 313
heterogeneous catalyst
Why are the most common heterogeneous catalysts finely divided or porous solids?
- Sat Mar 14, 2020 1:53 pm
- Forum: *Enzyme Kinetics
- Topic: Bottleneck
- Replies: 2
- Views: 356
Re: Bottleneck
No, but it may affect the amount of time a reaction needs to take place.
- Sat Mar 14, 2020 1:39 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Arrhenius Equation
- Replies: 3
- Views: 448
Re: Arrhenius Equation
A is the pre-exponential factor. According to collision theory, A is the frequency of collisions in the correct orientation.
- Sat Mar 14, 2020 1:36 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Activation energy
- Replies: 7
- Views: 432
Re: Activation energy
The activation energy of a reaction is measured in joules (J), kilojoules per mole (kJ/mol) or kilocalories per mole (kcal/mol)
- Sat Mar 14, 2020 1:20 pm
- Forum: General Rate Laws
- Topic: rate laws
- Replies: 8
- Views: 647
Re: rate laws
Yes, the rate would depend on the slowest step.
- Sat Mar 14, 2020 9:50 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: k
- Replies: 36
- Views: 1463
Re: k
A larger K does indicate a faster reaction.
- Sat Mar 14, 2020 9:40 am
- Forum: Experimental Details
- Topic: Rate Laws
- Replies: 8
- Views: 1227
Re: Rate Laws
They are determined according to experimental data.
- Sat Mar 14, 2020 9:31 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Slow step
- Replies: 2
- Views: 237
Slow step
If we are told that a reaction is the slow step in a mechanism, can we assume its reverse is slow enough to be ignored? Or should we be told that explicitly
- Sat Feb 29, 2020 2:06 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electrolytic Cell
- Replies: 2
- Views: 182
Re: Electrolytic Cell
A Galvanic cell converts chemical energy into electrical energy. An electrolytic cell converts electrical energy into chemical energy.
- Sat Feb 29, 2020 2:05 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic vs Voltaic Cells
- Replies: 4
- Views: 832
Re: Galvanic vs Voltaic Cells
Galvanic and voltaic cells are the same thing, but with different names. However, in comparison to galvanic cells, electrolytic cells convert electrical energy into chemical energy while galvanic cells convert chemical energy into electrical energy.
- Sat Feb 29, 2020 1:54 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: hydrogen electrodes
- Replies: 3
- Views: 197
Re: hydrogen electrodes
The standard hydrogen electrode is a redox electrode which forms the basis of the thermodynamic scale of oxidation-reduction potentials. Potentials of any other electrodes are compared with that of the standard hydrogen electrode at the same temperature.
- Sat Feb 29, 2020 1:46 pm
- Forum: Balancing Redox Reactions
- Topic: Reducing/Oxidizing Agents
- Replies: 13
- Views: 602
Re: Reducing/Oxidizing Agents
An oxidizing agent, or oxidant, gains electrons and is reduced in a chemical reaction. A reducing agent, or reductant, loses electrons and is oxidized in a chemical reaction.
- Sat Feb 29, 2020 1:37 pm
- Forum: Balancing Redox Reactions
- Topic: Cell Diagrams
- Replies: 14
- Views: 932
Re: Cell Diagrams
When drawing a cell diagram, the anode is placed on the left side while the cathode is placed on the right side.
- Sat Feb 22, 2020 12:22 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: relevance of salt bridge
- Replies: 9
- Views: 556
Re: relevance of salt bridge
The purpose of the salt bridge is to maintain charge balance because the electrons are moving from one-half cell to the other.
- Sat Feb 22, 2020 12:20 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: entropy based on molecular name/structure
- Replies: 2
- Views: 289
Re: entropy based on molecular name/structure
I think it's important to remember that the larger the molar mass, the greater the complexity which causes higher entropy.
- Sat Feb 22, 2020 12:04 am
- Forum: Calculating Work of Expansion
- Topic: isobaric compression
- Replies: 7
- Views: 1593
Re: isobaric compression
An isobaric expansion of a gas requires heat transfer to keep the pressure constant.
- Fri Feb 21, 2020 11:59 pm
- Forum: Van't Hoff Equation
- Topic: Van't Hoff Equation
- Replies: 3
- Views: 278
Re: Van't Hoff Equation
Van't hoff is derived from ΔG=ΔH−TΔS and ΔG= -RTlnK. The Van 't Hoff equation relates the change in the equilibrium constant, Keq, of a chemical reaction to the change in temperature, T, given the standard enthalpy change, ΔH.
- Fri Feb 21, 2020 11:48 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Derivations
- Replies: 5
- Views: 277
Re: Derivations
I don't think you need to memorize the derivations as long as you know how to use the equations given on the sheet.
- Sun Feb 16, 2020 11:04 pm
- Forum: Phase Changes & Related Calculations
- Topic: Fusion = Melting?
- Replies: 7
- Views: 974
Re: Fusion = Melting?
They are synonyms of one another.
- Sun Feb 16, 2020 10:54 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Entropy
- Replies: 3
- Views: 309
Re: Entropy
The standard entropy of a substance increases with an increase in the molar mass. This is because with the increase in molar mass the energy states of the atoms are more closely spaced to each other. Due to more closely spacing between the energy states, there is greater dispersal of energy at the g...
- Sun Feb 16, 2020 10:51 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Boltzman's Entropy Equation
- Replies: 4
- Views: 388
Re: Boltzman's Entropy Equation
Microstates is a term used to describe the number of different possible arrangements of molecular position and kinetic energy at a particular thermodynamic state. A process that gives an increase in the number of microstates increases the entropy.
- Sun Feb 16, 2020 10:48 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Positional entropy
- Replies: 3
- Views: 375
Re: Positional entropy
Positional entropy refers to the number of molecular positions or arrangements that a system can have, while thermal entropy refers to the amount of thermal energy that is not available for any useful work.
- Sun Feb 16, 2020 10:35 pm
- Forum: Van't Hoff Equation
- Topic: Van't Hoff's Equation
- Replies: 3
- Views: 378
Re: Van't Hoff's Equation
The Van 't Hoff equation relates the change in the equilibrium constant, Keq, of a chemical reaction to the change in temperature, T, given the standard enthalpy change, ΔH for the process.
- Mon Feb 10, 2020 12:39 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Isothermal Irreversible
- Replies: 3
- Views: 196
Re: Isothermal Irreversible
Yes, it is possible for isothermal reactions to be irreversible.
- Mon Feb 10, 2020 12:03 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Reversible and Irreversible Reactions
- Replies: 3
- Views: 409
Re: Reversible and Irreversible Reactions
In a irreversible reaction, the reactants react to form the products, which cannot revert back into reactants. In reversible reactions, as the reactants react with other reactants to form products, the products are reacting with other products to form reactants.
- Sun Feb 09, 2020 11:29 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Standard reaction entropy
- Replies: 3
- Views: 99
Re: Standard reaction entropy
In this formula, we are looking at changes in entropy.
- Sun Feb 09, 2020 11:04 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Comparing entropy change
- Replies: 2
- Views: 115
Re: Comparing entropy change
A decrease in the number of moles on the product side means lower entropy. An increase in the number of moles on the product side means higher entropy. If the reaction involves multiple phases, the production of a gas typically increases the entropy much more than any increase in moles of a liquid o...
- Sun Feb 09, 2020 10:30 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase Change Calculations
- Replies: 5
- Views: 161
Re: Phase Change Calculations
I believe it is given.
- Sun Feb 02, 2020 7:43 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: energy transfered
- Replies: 2
- Views: 92
Re: energy transfered
Delta U would equal delta H when work is equal to 0.
- Sun Feb 02, 2020 7:37 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Temperature
- Replies: 14
- Views: 522
Re: Temperature
A negative delta H would be exothermic.
- Sun Feb 02, 2020 7:27 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess’ Law
- Replies: 10
- Views: 568
Re: Hess’ Law
Hess's Law states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes.
- Sun Feb 02, 2020 7:24 pm
- Forum: Phase Changes & Related Calculations
- Topic: Liquid/Steam
- Replies: 3
- Views: 171
Re: Liquid/Steam
When steam comes into contact with skin, it condenses since the skin is at a lower temperature. The process of condensation releases energy (as heat) which causes the burn. Since the water is going through a phase change, the temperature of the steam is not getting lower even though energy is being ...
- Sun Feb 02, 2020 7:17 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Moles
- Replies: 8
- Views: 519
Re: Moles
You only count the coefficients of gaseous molecules.
- Sat Jan 25, 2020 4:55 pm
- Forum: Phase Changes & Related Calculations
- Topic: Calculating Bond Enthalpies
- Replies: 4
- Views: 108
Re: Calculating Bond Enthalpies
The change in enthalpy for a given reaction will be the combined total of the energy required to break any bonds that are broken and the energy released from any bonds that are formed.
- Sat Jan 25, 2020 4:48 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Decreasing volume
- Replies: 5
- Views: 181
Re: Decreasing volume
Due to Le Chatelier's Principle, the reaction would want to minimize pressure and would thus shift to the side with fewer moles.
- Sat Jan 25, 2020 4:39 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Value of X
- Replies: 7
- Views: 192
Re: Value of X
You would need to use an ICE table and then equate to K to solve for X.
- Sat Jan 25, 2020 4:32 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Partial Pressure vs. Concentration
- Replies: 5
- Views: 144
Re: Partial Pressure vs. Concentration
If not given additional info, either can be used since they represent the same quantity.
- Sat Jan 25, 2020 4:29 pm
- Forum: Ideal Gases
- Topic: Ideal Gases: Approximation
- Replies: 3
- Views: 224
Re: Ideal Gases: Approximation
Gases are most ideal at high temperature and low pressure so under these conditions the ideal gas law is more accurate. Under differing conditions, the ideal gas law is more of an approximation.
- Sat Jan 18, 2020 2:58 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Validating Approximation
- Replies: 2
- Views: 87
Re: Validating Approximation
Divide X by initial concentration and then multiply by 100 to get the percentage.
- Sat Jan 18, 2020 2:56 pm
- Forum: Ideal Gases
- Topic: Combined gas law
- Replies: 3
- Views: 150
Re: Combined gas law
The combined gas law is useful when given two pressures, volumes, or temperatures and asked for an unknown pressure, volume, or temp.
- Sat Jan 18, 2020 2:51 pm
- Forum: Ideal Gases
- Topic: Kp given instead of Kc
- Replies: 8
- Views: 445
Re: Kp given instead of Kc
After converting units, use the ideal gas law.
- Sat Jan 18, 2020 2:48 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ice table/quadratic
- Replies: 6
- Views: 256
Re: ice table/quadratic
If you get two positive X values, you should plug them back in to ensure the right answer gives a positive value when subtracted from initial concentration.
- Thu Jan 16, 2020 3:29 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Autoprotolysis
- Replies: 2
- Views: 94
Re: Autoprotolysis
If the concentration from the addition of an acid is very small, then it will not affect the pH that much. So autoprotolysis will be the determining factor in the pH.
- Sat Jan 11, 2020 6:13 pm
- Forum: Ideal Gases
- Topic: Units of Pressure
- Replies: 8
- Views: 233
Re: Units of Pressure
I believe most of the unit conversions will be provided on the formula sheet.
- Sat Jan 11, 2020 6:12 pm
- Forum: Ideal Gases
- Topic: Gas Laws
- Replies: 6
- Views: 151
Re: Gas Laws
I think it might be helpful to understand the concepts behind the other laws, since it would help you remember the individual relationships between variables of the ideal gas law.
- Sat Jan 11, 2020 6:08 pm
- Forum: Ideal Gases
- Topic: Conditions for Ideal Gases
- Replies: 5
- Views: 560
Re: Conditions for Ideal Gases
A gas behaves more like an ideal gas at higher temperature and lower pressure, since the potential energy due to intermolecular forces becomes less significant compared with the particles' kinetic energy, and the size of the molecules becomes less significant compared to the empty space between them.
- Sat Jan 11, 2020 6:02 pm
- Forum: Ideal Gases
- Topic: Law of Effusion, Kinetic Model, and Maxwell Distribution
- Replies: 3
- Views: 140
Re: Law of Effusion, Kinetic Model, and Maxwell Distribution
These topics may be covered later, but as of now, they haven't been discussed in class.
- Sat Jan 11, 2020 6:00 pm
- Forum: Ideal Gases
- Topic: Pa and bar? [ENDORSED]
- Replies: 3
- Views: 117
Re: Pa and bar? [ENDORSED]
Pa stands for Pascal and 100,000 Pascals is equal to one bar.
- Tue Dec 03, 2019 10:52 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Classifying Salts
- Replies: 5
- Views: 313
Re: Classifying Salts
You can do so by writing out the reaction for the salt and analyzing the products.
- Tue Dec 03, 2019 10:49 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: calculating pH
- Replies: 4
- Views: 285
Re: calculating pH
Find the molarity and then plug into the pH equation.
- Tue Dec 03, 2019 10:47 pm
- Forum: Polyprotic Acids & Bases
- Topic: ligands
- Replies: 4
- Views: 429
Re: ligands
Ligands act as Lewis bases (electron pair donors), and the central atom acts as a Lewis acid (electron pair acceptor). Ligands have at least one donor atom with an electron pair used to form covalent bonds with the central atom.
- Tue Dec 03, 2019 10:43 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: pH, pKA, KA, and B
- Replies: 2
- Views: 215
Re: pH, pKA, KA, and B
pKa = -log [Ka]. pH = - log [H+] Ka and Kb are related to each other through the ion constant for water, Kw with equation Kw = Ka x Kb.
- Tue Dec 03, 2019 10:33 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: pKa
- Replies: 2
- Views: 180
Re: pKa
Strong acids completely dissociate in their aqueous solutions. Thus the degree of dissociation is 100% which means Ka will be infinity after some time, which is why pKa is used mostly for weak acids.
- Wed Nov 27, 2019 1:10 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: How to take the log to get the pH?
- Replies: 8
- Views: 440
Re: How to take the log to get the pH?
The formula for pH is pH = -log[H+]. This means pH is the negative base 10 logarithm of the hydrogen ion concentration of a solution. To calculate it, take the log of the hydrogen ion concentration and reverse the sign to get the answer.
- Wed Nov 27, 2019 1:08 pm
- Forum: Bronsted Acids & Bases
- Topic: Acids vs Bases
- Replies: 5
- Views: 375
Re: Acids vs Bases
Also, acids change litmus paper red while bases change litmus paper blue.
- Wed Nov 27, 2019 1:03 pm
- Forum: Lewis Acids & Bases
- Topic: What is the correct definition of a base?
- Replies: 5
- Views: 351
Re: What is the correct definition of a base?
In chemistry, a base is a chemical species that donates electrons, accepts protons, or releases hydroxide (OH-) ions in aqueous solution. Types of bases include Arrhenius base, Bronsted-Lowry base, and Lewis base.
- Wed Nov 27, 2019 12:11 pm
- Forum: Sigma & Pi Bonds
- Topic: Nodal plane
- Replies: 3
- Views: 214
Re: Nodal plane
The sigma p bonding orbital is the lowest energy orbital which means it will have zero nodes. Then there is the pi bonding orbitals (1 node), the pi anti-bonding orbitals (2 nodes) and finally the anti-bonding sigma p orbital which has three nodes.
- Wed Nov 27, 2019 11:58 am
- Forum: Ionic & Covalent Bonds
- Topic: Dative Covalent Bonding
- Replies: 4
- Views: 449
Re: Dative Covalent Bonding
A dative covalent bond, or coordinate bond, is a bond where there is 1 pair of shared electrons between two atoms. The difference relative to a covalent bond is that in a dative covalent bond these electrons both come from one atom.
- Fri Nov 22, 2019 9:02 pm
- Forum: Bronsted Acids & Bases
- Topic: Strong vs Weak Acids
- Replies: 3
- Views: 266
Re: Strong vs Weak Acids
Additionally, the strength of an acid can be measured by its position on the pH scale.
- Fri Nov 22, 2019 8:52 pm
- Forum: Hybridization
- Topic: Knowing when hybridization occurs
- Replies: 6
- Views: 395
Re: Knowing when hybridization occurs
Hybridization occurs everytime there are multiple electron domains.
- Fri Nov 22, 2019 8:42 pm
- Forum: Hybridization
- Topic: Hybridization
- Replies: 3
- Views: 262
Re: Hybridization
The bond angle would increase when the s character increases because there is a decrease in the p character, which would mean less electron densities around the central atom.
- Fri Nov 22, 2019 8:36 pm
- Forum: Hybridization
- Topic: Valance Bond Theory
- Replies: 2
- Views: 212
Re: Valance Bond Theory
Valence bond theory describes the electronic structure of molecules. The theory says that electrons fill the atomic orbitals of an atom within a molecule. It also states that the nucleus of one atom is attracted to the electrons of another atom.
- Fri Nov 22, 2019 8:26 pm
- Forum: Biological Examples
- Topic: EDTA
- Replies: 3
- Views: 210
Re: EDTA
EDTA is used to bind metal ions in the practice of chelation therapy, such as for treating mercury and lead poisoning. It is used in a similar manner to remove excess iron from the body.
- Sat Nov 16, 2019 4:56 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge vs Octet Rule
- Replies: 12
- Views: 726
Re: Formal Charge vs Octet Rule
Yes, you should be more concerned with the octet rule first.
- Sat Nov 16, 2019 4:28 pm
- Forum: Lewis Structures
- Topic: Balanced Lewis Structures
- Replies: 6
- Views: 399
Re: Balanced Lewis Structures
Generally, what matters more is that your lewis structure is stable. Typically, the structure with the most formal charges on the atoms closest to zero is the more stable Lewis structure.
- Sat Nov 16, 2019 4:15 pm
- Forum: Sigma & Pi Bonds
- Topic: sigma bonds
- Replies: 3
- Views: 290
Re: sigma bonds
There can only be one sigma bond but multiple pi bonds.
- Sat Nov 16, 2019 4:12 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma and Pi Bonds
- Replies: 8
- Views: 498
Re: Sigma and Pi Bonds
Sigma bonds are end to end interactions that allow the atom to rotate around the internuclear axis and pi bonds are overlapping side by side bonds that don't allow atoms to rotate. There can only be one sigma bond between two atoms while there can be more than one pi bond.
- Sat Nov 16, 2019 4:01 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma And Pi Bond Concept Question
- Replies: 2
- Views: 145
Re: Sigma And Pi Bond Concept Question
If there is a pi bond present means that there is also a sigma bond present,making the bond strength stronger. Also, pi bonds will bond side by side, so if the atoms rotate, the pi bonds will break.
- Thu Nov 07, 2019 10:07 pm
- Forum: Electronegativity
- Topic: ionic character
- Replies: 9
- Views: 623
Re: ionic character
Since electronegativity is the tendency of an atom to attract a shared pair of electrons towards itself, greater ionic character implies a greater difference in electronegativities.
- Thu Nov 07, 2019 9:59 pm
- Forum: Properties of Light
- Topic: Frequency vs. Velocity
- Replies: 8
- Views: 811
Re: Frequency vs. Velocity
The speed of light is 3.0 x 10^8 m/s while the frequency can be determined according to wavelength.
- Thu Nov 07, 2019 9:53 pm
- Forum: Ionic & Covalent Bonds
- Topic: coordinate covalent bond
- Replies: 2
- Views: 162
Re: coordinate covalent bond
It is a covalent bond in which both shared electrons are donated by the same atom
- Thu Nov 07, 2019 7:55 pm
- Forum: Lewis Structures
- Topic: Oxygen
- Replies: 8
- Views: 1045
Re: Oxygen
This is because of an electron being added to an already half full orbital in oxygen, which results in electron-electron repulsion,lowering the ionization energy.
- Thu Nov 07, 2019 7:50 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Length differences
- Replies: 2
- Views: 181
Re: Bond Length differences
Bond length is determined by bond order, thus the higher the bond order, the shorter the bond length.
- Sun Nov 03, 2019 6:22 pm
- Forum: Trends in The Periodic Table
- Topic: Characteristics of Metallic and Nonmetallic Elements
- Replies: 2
- Views: 156
Re: Characteristics of Metallic and Nonmetallic Elements
Metallic elements tend to be lustrous, ductile, malleable, can conduct electricity, and tend to form cations in aqueous solutions. Nonmetals are non-lustrous, brittle, poor conductors, and tend to form anions in solutions.
- Sun Nov 03, 2019 4:00 pm
- Forum: Bond Lengths & Energies
- Topic: Resonance bond length
- Replies: 4
- Views: 253
Re: Resonance bond length
Yes, it is an average
- Sun Nov 03, 2019 3:04 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Distorted electrons
- Replies: 2
- Views: 152
Re: Distorted electrons
Electron distortion occurs when the electrons of the anion are attracted to the cation, causing the shape of the electron density to change slightly.
- Sun Nov 03, 2019 2:55 pm
- Forum: Dipole Moments
- Topic: Induced Dipole
- Replies: 5
- Views: 216
Re: Induced Dipole
Induced dipoles can occur when one molecule with a permanent dipole repels another molecule's electrons.
- Sun Nov 03, 2019 2:46 pm
- Forum: Electronegativity
- Topic: Electron Affinity
- Replies: 3
- Views: 109
Re: Electron Affinity
Electronegativity is the likelihood of an atom to attract electrons, and electron affinity is the amount of energy released when an electron is added to a neutral atom.
- Fri Oct 25, 2019 11:50 am
- Forum: Resonance Structures
- Topic: Delocalization
- Replies: 3
- Views: 102
Re: Delocalization
Delocalized electrons are electrons in a molecule or ion that aren't associated with a single atom or a covalent bond. It occurs when electric charge is spread over more than one atom.
- Fri Oct 25, 2019 11:45 am
- Forum: Lewis Structures
- Topic: Lewis Structures: Lone pairs as dots or lines?
- Replies: 5
- Views: 285
Re: Lewis Structures: Lone pairs as dots or lines?
I would use dots instead of lines to keep things clear and avoid confusion.
- Fri Oct 25, 2019 11:40 am
- Forum: Sigma & Pi Bonds
- Topic: Importance of Sigma/Pi Bonds
- Replies: 5
- Views: 591
Re: Importance of Sigma/Pi Bonds
They are used to predict the behavior of molecules in molecular orbital theory, which describes the electronic structure of molecules.
- Fri Oct 25, 2019 11:34 am
- Forum: Ionic & Covalent Bonds
- Topic: Octet Rule Exceptions
- Replies: 3
- Views: 161
Re: Octet Rule Exceptions
H and He are exceptions to the octet rule since their full shell is two electrons. Li and Be are metals, making them more likely to lose electrons and turn into cations.
- Fri Oct 25, 2019 11:28 am
- Forum: Ionic & Covalent Bonds
- Topic: Bond length
- Replies: 11
- Views: 392
Re: Bond length
The bond length is the average distance between the nuclei of two bonded atoms in a molecule. It is an average due to a bond not being a static structure, but instead one in which atoms vibrate because of thermal energy.
- Sat Oct 19, 2019 4:02 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Aufbau
- Replies: 3
- Views: 185
Aufbau
Can someone explain the Aufbau Principle in greater detail?
- Sat Oct 19, 2019 3:50 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Cr and Cu
- Replies: 5
- Views: 258
Re: Cr and Cu
They are exceptions because they do not follow the normal electron configuration pattern. This is because a completely full or half full d sub-level is more stable than a partially filled d sub-level, so an electron from the 4s orbital is excited and rises to a 3d orbital.
- Sat Oct 19, 2019 3:42 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Exceptions (Cr and Cu)
- Replies: 2
- Views: 136
Re: Exceptions (Cr and Cu)
A completely full or half full d sub-level is more stable than a partially filled d sub-level, so an electron from the 4s orbital is excited and rises to a 3d orbital.
- Thu Oct 17, 2019 5:35 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Stern and Gerlach Experiment
- Replies: 2
- Views: 92
Stern and Gerlach Experiment
Why were silver atoms used in the experiment, as opposed to other atoms?
- Thu Oct 17, 2019 4:15 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal Planes
- Replies: 7
- Views: 363
Nodal Planes
What are nodal planes and how are they relevant to orbital shapes?
- Sun Oct 13, 2019 12:51 pm
- Forum: Properties of Electrons
- Topic: History of the QM Equations
- Replies: 2
- Views: 114
Re: History of the QM Equations
They were developed in the 1920s, during the time period the phrase "quantum mechanics" was coined.
- Sun Oct 13, 2019 12:42 pm
- Forum: Photoelectric Effect
- Topic: Removing an atom
- Replies: 3
- Views: 106
Re: Removing an atom
This is based on ionization energy, which is the amount of energy required to remove an electron from an atom.
- Sun Oct 13, 2019 12:20 pm
- Forum: DeBroglie Equation
- Topic: DeBroglie Equation
- Replies: 9
- Views: 348
Re: DeBroglie Equation
Light does not have mass, so the DeBroglie equation would not work.
- Sun Oct 13, 2019 12:13 pm
- Forum: Properties of Electrons
- Topic: Quantum electrons
- Replies: 2
- Views: 197
Re: Quantum electrons
There are four quantum numbers which include the principal quantum number (n), the angular quantum number (l), the magnetic quantum number (m), and the spin quantum number (s). When electrons are added to atoms, they take the lowest available value of n. Also, all orbitals in a subshell must have on...
- Sat Oct 12, 2019 8:21 pm
- Forum: Properties of Light
- Topic: How does x-ray crystallography work?
- Replies: 2
- Views: 98
How does x-ray crystallography work?
How is x-ray crystallography used to determine structure?
- Thu Oct 03, 2019 1:03 am
- Forum: SI Units, Unit Conversions
- Topic: Easy method to memorize prefixes?
- Replies: 2
- Views: 97
Easy method to memorize prefixes?
I have a hard time memorizing prefixes, especially ones that aren't as common. Is there any way to remember them more effectively?
- Thu Oct 03, 2019 12:50 am
- Forum: Properties of Light
- Topic: EM Spectrum
- Replies: 4
- Views: 231
EM Spectrum
For class, is it necessary to memorize the electromagnetic spectrum, along with its respective frequencies and wavelengths?
- Thu Oct 03, 2019 12:44 am
- Forum: Significant Figures
- Topic: Does molar mass count for sig figs?
- Replies: 6
- Views: 2954
Does molar mass count for sig figs?
Do the values of the molar masses we use for calculations affect the number of significant figures the answer contains?
- Thu Oct 03, 2019 12:33 am
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Molecular weight/Atomic weight
- Replies: 2
- Views: 132
Re: Molecular weight/Atomic weight
Formula weight is the sum of the atomic weights of the atoms in its empirical formula. Molecular weight is a molecule's average mass as calculated by adding together the atomic weights of the atoms in the molecular formula. Atomic weight is the mass of one mole of the given element.
- Wed Oct 02, 2019 1:26 am
- Forum: Balancing Chemical Reactions
- Topic: How do oxidation numbers help you balance equations?
- Replies: 2
- Views: 187
How do oxidation numbers help you balance equations?
How does assigning oxidation numbers help you balance chemical equations? I saw my TA use it for a problem during discussion but wasn't able to get clarification. Thanks.