## Search found 100 matches

Sat Mar 14, 2020 8:29 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Reaction order
Replies: 4
Views: 68

### 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: 345

### Re: Test 2 Return

Sat Mar 14, 2020 1:58 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: heterogeneous catalyst
Replies: 4
Views: 39

### 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: 70

### 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: 133

### 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: 55

### 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: 125

### 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: 7
Views: 130

### Re: k

A larger K does indicate a faster reaction.
Sat Mar 14, 2020 9:40 am
Forum: Experimental Details
Topic: Rate Laws
Replies: 2
Views: 341

### 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: 31

### 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: 21

### 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: 40

### 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: 25

### 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: 77

### 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: 127

### 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: 60

### 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: 107

### 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: 143

### 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: 62

### 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: 66

### 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: 136

### 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: 103

### 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: 142

### 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: 79

### 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: 26

### 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: 28

### 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: 53

### 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: 27

### 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: 35

### 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: 50

### 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: 24

### 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: 167

### 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: 145

### 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: 38

### 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: 115

### 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: 31

### 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: 49

### 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: 55

### 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: 51

### 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: 82

### 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: 27

### 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: 47

### 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: 99

### 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
Replies: 6
Views: 55

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: 37

### 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: 73

### 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: 79

### 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: 68

### 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: 42

### 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: 35

### 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: 56

### 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: 69

### 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: 132

### 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: 53

### 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: 51

### 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: 81

### 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: 84

### 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: 78

### 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: 62

### 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: 141

### 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: 49

### 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: 65

### 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: 70

### 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: 31

### 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: 37

### 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: 5
Views: 166

### 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: 89

### 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: 56

### 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: 111

### 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: 38

### 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: 233

### 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: 251

### 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: 41

### 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: 94

### 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: 38

### 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: 42

### 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: 57

### 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: 54

### 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: 94

### 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: 47

### 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: 36

### 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: 61

### 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: 300

### 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: 54

### 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: 113

### 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: 40

### 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: 60

### 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: 47

### 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: 59

### 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: 115

### 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: 28

### 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: 45

### 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: 134

### 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: 25

### 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: 34

### 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: 66

### 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: 85

### 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: 224

### 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: 76

### 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