Search found 107 matches

Fri Mar 13, 2020 3:38 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calculating lnQ in Nernst Equation
Replies: 2
Views: 50

Re: Calculating lnQ in Nernst Equation

The anode goes on the top and the cathode goes on the bottom.The anode is thought to be the diluted concentration and the cathode is concentrated. As the reaction progresses, the concentration will increase in the left (oxidation) anode as the solid electrode dissolves, while the concentration in th...
Fri Mar 13, 2020 3:01 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrodes
Replies: 4
Views: 44

Re: Electrodes

Pt (s) is necessary when there is no other solids in the half reactions.
Fri Mar 13, 2020 2:58 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Slow step
Replies: 7
Views: 125

Re: Slow step

Abby Soriano 1J wrote:The problem will most likely specify which of the steps is the slow step. You will probably be asked if a proposed mechanism matches the observed rate law, but you won't need to actually calculate a value for the slow step.

If the rate matches the observed rate law is that the slowest step?
Fri Mar 13, 2020 2:52 pm
Forum: Zero Order Reactions
Topic: catalyst
Replies: 5
Views: 105

Re: catalyst

A zero order reaction can simply be when a material such as the surface or catalyst are saturated by the reactants so no a catalyst isn't necessary to make a reaction zero order. In this type of reaction, the limiting factor is something besides concentration which can possibly be a catalyst, but th...
Fri Mar 13, 2020 2:25 pm
Forum: First Order Reactions
Topic: Pseudo-First Order Reaction
Replies: 4
Views: 79

Re: Pseudo-First Order Reaction

You can use pseudo first order when trying to find out how the reaction is dependent on only one reactant. This is done by assuming the other concentrations are very large and do not change, so only our molecule of concern is studied. If we have two reactants and we test each one individually by ma...
Fri Mar 13, 2020 2:15 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius equation
Replies: 2
Views: 44

Arrhenius equation

How do we solve for Ea in the Arrhenius equation or is it always given?
Sun Mar 08, 2020 12:57 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Determining the cathode/anode
Replies: 9
Views: 184

Re: Determining the cathode/anode

The most negatively reduced standard cell potential occurs at the cathode and the most positive standard cell potential occurs at the anode.
Sat Mar 07, 2020 1:57 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Concentration cell
Replies: 8
Views: 158

Concentration cell

What is the main difference between a concentration cell and a galvanic cell in a cell diagram?
Sat Mar 07, 2020 1:51 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Arrhenius Equation
Replies: 6
Views: 77

Re: Arrhenius Equation

705302428 wrote:you use it to find the equilibrium constant K. It defines the relationship between activation energy, the equilibrium constant, temperature, and A which is the frequency factor.

How do we get A or the frequency factor?
Sat Mar 07, 2020 1:47 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calculating ln Q
Replies: 20
Views: 261

Re: Calculating ln Q

Q is the reaction quotient, [Products]/[Reactants] for concentration cells the lower concentration is the products. Or the cathode concentration is the reactants and the anode concentration is the products. Why is the cathode concentration the reactant if the the cell diagram shows it in the order ...
Mon Mar 02, 2020 4:48 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 5G.17 Question [ENDORSED]
Replies: 3
Views: 170

Re: 5G.17 Question[ENDORSED]

Please explain what specific aspect of this problem that is making you stuck. The reaction is given as I 2 (g) --> 2 I (g) but on the graph is shows that I is the reactant and I 2 is the product. Is this because the reactants are favored at equilibrium in the given reaction? Or can we depict either...
Mon Mar 02, 2020 4:41 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 5G.17 Question [ENDORSED]
Replies: 3
Views: 170

5G.17 Question[ENDORSED]

Depict the progress of the reaction graphically (as in Fig. 5G.1) for the reaction:
I2(g) --> 2 I(g)
The graph below is the solution shown in the book can someone explain why I is shown as the reaction and I2 as the product if the reaction shows it the other way.
Sun Mar 01, 2020 4:00 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Units for delta G
Replies: 14
Views: 258

Re: Units for delta G

VPatankar_2L wrote:Since one Faraday is 96485 C/mol, it can be multiplied by n (moles) in the equation delta G = -nFE to just get kJ.

What are the units for E and how do we get to Joules from coulombs?
Sun Mar 01, 2020 3:54 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt bridges
Replies: 11
Views: 122

Re: Salt bridges

Kavya Immadi 3D wrote:Without a salt bridge, the cell would stop working soon because the cathode would be too negative and would repulse the electrons which would stop working.

If this were to occur, would the cathode begin releasing electrons back to the anode since it repulses the electrons?
Sun Mar 01, 2020 3:47 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard Cell Potential
Replies: 3
Views: 45

Re: Standard Cell Potential

Standard Cell Potentials can also be negative, but it's more likely to encounter positive standard cell potentials because this means the galvanic cell is favorable and can do work spontaneously without any outside power source such as a regular battery meanwhile a negative standard cell potential w...
Sun Mar 01, 2020 3:41 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Finding N
Replies: 6
Views: 122

Re: Finding N

n is the moles of electrons transferred where transfer is the number of electrons going from the oxidized species to the reduced. To find this, we must balance the half reactions and then balance the half reactions against one another so that the number of electrons is equal to each other in order t...
Sun Mar 01, 2020 3:18 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: ∆G and ∆G°
Replies: 7
Views: 107

Re: ∆G and ∆G°

This also applies for ∆G. ∆G° is simply free energy measured under standard conditions at 1 atm and 25°C and ∆G is the free energy measured under a different pressure and temperature which must be calculated for a reaction.
Mon Feb 24, 2020 2:43 pm
Forum: Balancing Redox Reactions
Topic: Homework Question 6K.5 (part b)
Replies: 1
Views: 45

Homework Question 6K.5 (part b)

Balance each of the following skeletal equations by using oxidation and reduction half-reactions. All the reactions take place in basic solution. Identify the oxidizing agent and reducing agent in each reaction. b). Reaction of bromine with itself (disproportionation) in aqueous solution: Br 2 (l) -...
Sun Feb 23, 2020 2:07 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic/Voltaic cells
Replies: 3
Views: 29

Re: Galvanic/Voltaic cells

We can see galvanic cells in non-rechargeable batteries where there is a spontaneous redox reaction in the flow of electrical charges and electrons flow from the anode (negative since electrons are built up here) to the cathode (positive since it is gaining electrons).
Sun Feb 23, 2020 2:01 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Positive Voltage
Replies: 2
Views: 17

Positive Voltage

In this course should we always assume a more positive standard reduction meaning the reaction is more likely to undergo reduction and be on the cathode side (will lead to a positive voltage) ? If not how can we find out if the reaction will be on the anode side vs the cathode side?
Sun Feb 23, 2020 1:50 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Voltage Energies
Replies: 3
Views: 37

Re: Voltage Energies

When calculating the equation for overall cell potential you do not need to change the sign of E naught for the reverse reaction.
Sun Feb 23, 2020 1:46 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Using Pt
Replies: 7
Views: 115

Re: Using Pt

When is it necessary to use Pt(s) in the skeletal equation of a redox reaction? In the example that Dr. Lavelle gave in class: 2Fe3+(aq) + Cu(s) -> Cu2+(aq) + 2Fe2+ although platinum is part of the redox reaction, platinum is an inert conductor that is transferring e-, as there is no conducting sol...
Sun Feb 23, 2020 1:43 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Finding n
Replies: 6
Views: 71

Re: Finding n

"n" means moles of electrons and can easily be found by looking at your balanced redox reaction and looking at the number of electrons that were transferred. So this is the number of moles of electrons transferred after the entire redox reaction and not the total of electrons transferred ...
Sun Feb 16, 2020 3:43 am
Forum: Van't Hoff Equation
Topic: What is this? [ENDORSED]
Replies: 7
Views: 136

Re: What is this?[ENDORSED]

What are the constants in this equation? (example: constant pressure)
Sun Feb 16, 2020 3:32 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: delta U= delta H
Replies: 6
Views: 145

Re: delta U= delta H

Delta U= q+w and under constant pressure, qp=delta H and when no work is done Delta U=Delta H
Sun Feb 16, 2020 3:00 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: spontaneity
Replies: 34
Views: 675

Re: spontaneity

A negative delta G means that the reaction is spontaneous.
Sun Feb 16, 2020 2:37 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Delta E
Replies: 11
Views: 232

Delta E

What is the difference between delta E and delta U?
Sun Feb 16, 2020 2:29 am
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: Boltzmann Equation
Replies: 10
Views: 145

Re: Boltzmann Equation

Sartaj Bal 1J wrote:The Boltzmann equation is used to represent the relationship between degeneracy, w, and entropy. Degeneracy is the number of ways of achieving a given energy state. The Boltzmann equation also includes the Boltzmann constant which is 1.381*10^-23 J*K^-1.

Can we calculate degeneracy? If so how?
Sun Feb 09, 2020 1:50 am
Forum: Calculating Work of Expansion
Topic: 4A.3 part c
Replies: 3
Views: 45

Re: 4A.3 part c

Usually delta U=q+w but there is not heat (q) exchanged in this problem so delta U= w
Sun Feb 09, 2020 1:45 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: reversible vs irreversible work
Replies: 7
Views: 82

Re: reversible vs irreversible work

Sometimes it's also easy to think conceptually whether a process can be undone (reversible) or not (irreversible) such as combustion, once something is burned then it cannot be undone, therefore it is an irreversible system.
Sun Feb 09, 2020 1:20 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: HW Question
Replies: 2
Views: 34

Re: HW Question

The system consists of both kettle + water, and the surroundings supply the heat. Enough supplied heat is needed to raise the temperature of both the vessel and the water because of the idea that heat moves from a hot object to a cold object so both need to be heated because if just the vessel is he...
Sun Feb 09, 2020 12:59 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Confused about Heat of Combustion
Replies: 2
Views: 28

Re: Confused about Heat of Combustion

She may be referring to the equation
q=n*C*(delta T)
where q is heat transferred, n is # of moles, C is the molar heat capacity, and delta T is change in temperature.
Sun Feb 09, 2020 12:50 am
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: Going from delta S to delta H
Replies: 2
Views: 46

Re: Going from delta S to delta H

delta S(surrounding)= -delta H/T
This equation can manipulated to solve for delta H given delta S
Sun Feb 02, 2020 3:23 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Closed vs isolated systems
Replies: 24
Views: 205

Re: Closed vs isolated systems

In a closed system, matter does not change, but the energy (heat) can with the surroundings. In an isolated system matter doesn't change and energy cannot change meaning that the system is insulated.
Sun Feb 02, 2020 3:20 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Enthalpy vs. Heat
Replies: 6
Views: 53

Re: Enthalpy vs. Heat

PranaviKolla2B wrote:Does anyone have any good videos explaining enthalpy and the related equations?

Sun Feb 02, 2020 3:13 am
Forum: Calculating Work of Expansion
Topic: Reversible vs. Irreversible
Replies: 1
Views: 27

Re: Reversible vs. Irreversible

Irreversible reactions are reactions in which the reactants convert to products and where the products cannot convert back to the reactants. In reversible reactions, as the reactants react with other reactants to form products, the products are reacting with other products to form reactants. Reversi...
Sun Feb 02, 2020 2:21 am
Forum: Calculating Work of Expansion
Topic: L atm and J
Replies: 3
Views: 38

Re: L atm and J

The joules unit number 101.33 J converts to 1 l atm, one Liter-atmosphere. It is the equal energy value of 1 Liter-atmosphere but in the joules energy unit alternative.
Sun Feb 02, 2020 2:10 am
Forum: Ideal Gases
Topic: pv=nrt
Replies: 9
Views: 124

Re: pv=nrt

Kind of like what the previous person said, R is a gas constant, so that can't really be changed (given on our equations sheet). For everything else though, yes there could be change. That's also where the mini-questions during lectures are formed "What would happen to ____ if ____ increased?&...
Sat Jan 25, 2020 7:06 pm
Forum: Phase Changes & Related Calculations
Topic: revere reactions
Replies: 7
Views: 51

Re: revere reactions

Would this be the same for going up a phase? Would it be endothermic in this case since now there is more heat required to break down the phase like a solid to liquid? Yes going up a phase requires energy to be absorbed otherwise defined as an endothermic reaction in order to go from a solid (low e...
Sat Jan 25, 2020 7:02 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Heat Capacity
Replies: 5
Views: 52

Re: Heat Capacity

Molar heat capacity is the amount of heat needed to raise the temperature of one mole of a pure substance by one degree Kelvin. Specific heat capacity is the amount of heat necessary to raise the temperature of one gram of a pure substance by one degree Kelvin.
Sat Jan 25, 2020 6:59 pm
Forum: Phase Changes & Related Calculations
Topic: Endothermic and Exothermic
Replies: 13
Views: 97

Re: Endothermic and Exothermic

Endothermic Reactions require heat or absorb it to overcome the activation energy to form products. In an exothermic reaction, heat is released or "exits" the reaction to form the product and no longer can overcome the activation energy in the reverse reaction unless more heat is absorbed.
Sat Jan 25, 2020 6:53 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: enthalpy reaction
Replies: 4
Views: 31

Re: enthalpy reaction

Elena Bell 1C wrote:We do reactants minus the products for bond enthalpies because it is broken minus made. The bonds broken require energy, while forming bonds releases energy.

Why is it that in order to break bonds, energy is needed? And to form bonds energy is released?
Sat Jan 25, 2020 6:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Excluding H2O from Ka and Kb
Replies: 5
Views: 50

Re: Excluding H2O from Ka and Kb

Water is a pure liquid and has an activity equal to 1, therefore, it does not affect the equilibrium constant.
Sun Jan 19, 2020 12:20 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Concentrations
Replies: 12
Views: 98

Re: Concentrations

I'm not sure if this answers your question but if the temperature is the same the concentration does not change the equilibrium constant (k). However, if you change the temperature it does change the equilibrium constant. So temperature is the only thing that can affect the the equilibrium constant ?
Sun Jan 19, 2020 12:16 am
Forum: Ideal Gases
Topic: R constant in Ideal Gas Law
Replies: 4
Views: 42

R constant in Ideal Gas Law

How do we know what units to use for the R constant in the Ideal Gas Law?
Sat Jan 18, 2020 11:16 pm
Forum: Ideal Gases
Topic: Ideal Gas meaning
Replies: 7
Views: 145

Re: Ideal Gas meaning

Kevin Antony 2B wrote:At low temperatures, most gases are going to act ideally. In this course, we'll probably only deal with ideal gases because this allows for us to apply PV=nRT and infer molecular kinetic energy based on temperature.

How do we know when to apply the ideal gas equation in a problem?
Sat Jan 18, 2020 11:14 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5 %
Replies: 4
Views: 36

Re: 5 %

If you solve Ka or Kb by the approximate method and exceed 5% in order to obtain as accurate an answer as possible, the quadratic method must be used. So I guess, it's just a method of making finding the solution simpler instead of going through the whole quadratic formula if it isn't necessary.
Sat Jan 18, 2020 10:52 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatliers Principle In relation to pressure
Replies: 6
Views: 50

Re: Le Chatliers Principle In relation to pressure

According to the ideal gas law, PV = nRT, P = nRT/V = concentration (=n/V) * RT. So [partial pressure = concentration * RT]. The way I see it is concentration is moles per liter which means the more moles, the higher the Molarity or Concentration, and as said in the comment above, partial pressure ...
Sat Jan 11, 2020 4:43 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Significance of principle
Replies: 6
Views: 54

Re: Significance of principle

Le Chatelier's principle can be used to predict the behavior of a system due to changes in pressure, temperature, or concentration. This principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish ...
Sat Jan 11, 2020 4:39 pm
Forum: Ideal Gases
Topic: R in PV=nRT
Replies: 34
Views: 737

Re: R in PV=nRT

PV=nRT is the Ideal Gas Law equation. To answer your question, the R is the ideal gas law constant and there are varying corresponding values (for the most part, problems will specify which value to use.) Some examples can include bar or atm. When do we use the ideal gas law equation? How does it r...
Sat Jan 11, 2020 3:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Why does only Temp affect K?
Replies: 10
Views: 348

Re: Why does only Temp affect K?

Temperature affects K c because the forward reaction is either exothermic or endothermic. If the forward reaction is endothermic, then the K c value will be larger when the temperature is higher since the forward reaction will absorb the added heat and produce a greater proportion of products to re...
Sat Jan 11, 2020 3:49 pm
Forum: Ideal Gases
Topic: Solids and Liquids [ENDORSED]
Replies: 10
Views: 121

Re: Solids and Liquids[ENDORSED]

I agree with Fiona and McKenna! However, I am still confused on the matter of liquids being pure substancews. Can someone clarify how a liquid is different from an aqueous solution and give examples of each? From what I understand, aqueous solutions have a solute and solvent, and liquids do not. Ca...
Sat Jan 11, 2020 2:13 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Tables
Replies: 5
Views: 56

Re: ICE Tables

Yes an ICE box is only used for gases and aqueous reagents because they are not pure substances and can change over the course of a reaction. In establishing equilibrium constants, solids and liquids are not used/considered due to the fact that they're pure substances that don't change.
Sat Dec 07, 2019 11:03 pm
Forum: Coordinate Covalent Bonds
Topic: Cisplatin
Replies: 3
Views: 154

Cisplatin

What else besides knowing that the Cl atoms in cisplatin can attach to DNA bases to initiate cell death in chemotherapy is necessary to know about cisplatin?
Sat Dec 07, 2019 10:43 pm
Forum: Bronsted Acids & Bases
Topic: Amphoteric
Replies: 2
Views: 109

Re: Amphoteric

Amphoteric molecules usually contain the elements that lie on the diagonal border (metalloids) between the metals and nonmetals where metallic character blends into non-metallic character and the oxides of these elements have both acidic and basic character.
Sat Dec 07, 2019 10:27 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 5300

Re: MARSHMALLOW- FINAL REVIEW SESSION[ENDORSED]

CHo_3I wrote:
SarahSteffen_LEC4 wrote:On question number 21 of the Marshmallow review. Why does iron have a +2 charge if two of the nitrogens on the porphyrin ligand have a +1 charge?

The two nitrogens actually have a -1 charge, not +1.

How is the charge for the nitrogens -1?
Sat Dec 07, 2019 9:49 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 5300

Re: MARSHMALLOW- FINAL REVIEW SESSION[ENDORSED]

#16 why is the trigonal planar shape considered nonpolar, how did we determine this ?
Sat Dec 07, 2019 5:01 pm
Forum: Administrative Questions and Class Announcements
Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
Replies: 111
Views: 5300

Re: MARSHMALLOW- FINAL REVIEW SESSION[ENDORSED]

Joanne Kang 3I wrote:min marshmallows 1c... why isn't it neutral?

NH4+ donates a proton and H20 accepts a proton, therefore NH4+is acidic.
Fri Dec 06, 2019 1:52 pm
Forum: Dipole Moments
Topic: Intermolecular Forces
Replies: 3
Views: 113

Intermolecular Forces

Are London Dispersion forces and Van Der Waals forces the same type of intermolecular force? Why is there always Van Der Waals forces?
Fri Dec 06, 2019 12:32 am
Forum: Naming
Topic: Naming Anionic Ligands
Replies: 3
Views: 67

Naming Anionic Ligands

When we name anionic ligands in coordination compounds do we refer to anions that end in -ide as -ido or just -o as a replacement because the book uses -ido and Dr. Lavelle presents both in his LIGAND NAMES IN COORDINATION COMPOUNDS pdf. An example is chloride, when it is named in a coordination com...
Sun Dec 01, 2019 1:36 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate = more than one lone pair?
Replies: 4
Views: 50

Re: Polydentate = more than one lone pair?

Can we determine the denticity (monodentate, bidentate, polydentate, etc.) of a ligand by simply looking at the coordination compound name? If so, how?
Sun Dec 01, 2019 1:21 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: strong or weak base?
Replies: 13
Views: 211

Re: strong or weak base?

A strong base is a base that is 100% ionized in solution and if it is less than 100% ionized in solution, it is a weak base. All strong bases are OH– compounds.
Sun Dec 01, 2019 1:10 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: dipole-dipole in a solid phase vs gas phase
Replies: 15
Views: 290

Re: dipole-dipole in a solid phase vs gas phase

With gases, they occupy more space so the attraction between the molecules are weak. Solids on the other hand are more restricted in their movement, so they have stronger dipole-dipole interactions than gases would. So are all intermolecular bonds between gases generally weaker than those between s...
Sun Dec 01, 2019 1:03 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Amphoteric vs. Amphiprotic
Replies: 4
Views: 50

Re: Amphoteric vs. Amphiprotic

Amphoteric refers to the ability to react with an acid or base. An amphiprotic substance is a substance that transfers (accepts or donates) H+ ions.
Sun Dec 01, 2019 12:36 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Sigma and Pi Bonds
Replies: 12
Views: 604

Re: Sigma and Pi Bonds

All bonds have at least one sigma bond the other bonds are pi bonds.
Sat Nov 23, 2019 4:02 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Boiling Points
Replies: 9
Views: 135

Re: Boiling Points

I'm confused between the melting point and the boiling point of a compound? Is this referring to the same thing? There is a difference in which the boiling point is the temperature where a material goes from liquid to a gas and melting point is the temperature where a material changes from a solid ...
Sat Nov 23, 2019 3:37 pm
Forum: Administrative Questions and Class Announcements
Topic: Thanksgiving Break
Replies: 4
Views: 104

Re: Thanksgiving Break

My TA sent out an email saying that if you do not have discussion this week both week 9 and 10 homework can be turned in the following week. I'm not sure if it's like this for all TA's.
Sat Nov 23, 2019 3:32 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Bronsted acids
Replies: 5
Views: 144

Re: Bronsted acids

A Bronsted acid is an H+ donor (proton donor), and a bronsted base is an H+ acceptor (proton acceptor). In order for a bronsted base to accept an H+ ion, it uses its lone pair of electrons to bind to it. You can then see the connection between a bronsted base and a Lewis base (<- electron pair dono...
Sat Nov 23, 2019 3:28 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Sphere
Replies: 6
Views: 78

Re: Coordination Sphere

The first coordination sphere is all molecules or ions directly attached the central metal atom shown below.
Sat Nov 23, 2019 12:18 am
Forum: Shape, Structure, Coordination Number, Ligands
Replies: 2
Views: 40

A ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. Ligands are Lewis bases due to the availability of a lone pair of electrons that can be donated to create a coordinate covalent bonds.
Sat Nov 23, 2019 12:04 am
Forum: Biological Examples
Topic: Ringlike structures + chelating ligands
Replies: 2
Views: 31

Re: Ringlike structures + chelating ligands

A ligand is chelating if it has two or more points of attachment or coordinate covalent bonds to a metal atom or metal ion. When a ligand is chelating a ring structure is formed creating ring-forming groups known as chelating groups.
Sun Nov 17, 2019 1:15 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Van Der Waals Interaction
Replies: 11
Views: 141

Van Der Waals Interaction

Do all molecules have Van Der Waals interactions? What is the order of strongest to weakest interactions ?
Sun Nov 17, 2019 12:38 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 6
Views: 161

Re: Lone Pairs

lone pairs count towards molecular geometry not electron domain geometry. so in the case of 4 electron domains (3 bonding and one lone pair), the electron domain geometry would be tetrahedral while the molecular geometry would be trigonal pyramidal. So if asked in a question what shape a certain mo...
Sat Nov 16, 2019 6:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent or Angular
Replies: 13
Views: 333

Re: Bent or Angular

So, the bond angle in H 2 O is 104.5 degrees (from the textbook). On test 2, should we state that the bond angle for all angular molecules is 104.5 degrees or should we just say less than 120 degrees? Angular molecules can have varying bond angles depending on the amount of lone pairs there are suc...
Sat Nov 16, 2019 6:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR and Polarity
Replies: 4
Views: 44

Re: VSEPR and Polarity

Polar molecules are asymmetrical in electronegativity and the geometry or formation. Asymmetrical electronegativity meaning there is an atom with a partial positive charge surrounding an atom with a partial negative charge with an electronegativity difference of 0.5-1.6. Asymmetrical formation assur...
Sat Nov 16, 2019 5:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape
Replies: 6
Views: 98

Re: Shape

DesireBrown3K wrote:This photo is from the textbook of all the shapes we should know for test 2.

[img]Screenshot%202019-11-16%2017.24.28.png[/img]

The book names what Dr. Lavelle called "bent" as "angular" which is the correct term to use?
Thu Nov 07, 2019 3:48 pm
Forum: SI Units, Unit Conversions
Topic: Photons
Replies: 3
Views: 165

Re: Photons

If eV is on the test convert it to joules(on the equation sheet) to ensure you are still in SI units but eV is used to measure energy and can thus measure the energy in a photon.
Thu Nov 07, 2019 3:47 pm
Forum: Bond Lengths & Energies
Topic: Bond strengths
Replies: 9
Views: 100

Re: Bond strengths

A longer bond means a weaker bond as the interaction between the atoms is weaker. Shorter bonds mean a strong pull between the nuclei of the two atoms and thus it requires more energy to break which means it is stronger.
Thu Nov 07, 2019 3:43 pm
Forum: Octet Exceptions
Topic: Easy way to remember octet exceptions
Replies: 4
Views: 68

Re: Easy way to remember octet exceptions

Any atom with a d orbital has the octet exception. Atoms in row one and two only have the p and s orbitals and thus eight valence electrons, the p orbital has six and the s orbital two. With the addition of a d orbital, atoms are able to accommodate more than eight valence electrons by putting some ...
Thu Nov 07, 2019 3:39 pm
Forum: Electronegativity
Topic: Trend of Electronegativity
Replies: 22
Views: 490

Re: Trend of Electronegativity

Does ionization have the same trend? Ionization energy has the exact same trend. Ionization energy and electronegativity go hand in hand, the more electronegative an atom is the more it wants an electron and thus the more tightly it will hold on to its own electrons. Across a period, atoms gain pro...
Thu Nov 07, 2019 3:36 pm
Forum: Electronegativity
Topic: Trend of Electronegativity
Replies: 22
Views: 490

Re: Trend of Electronegativity

Electronegativity increases in an overall diagonal line starting with Francium as the least electronegative and Fluorine as the most electronegative. This occurs because as you move up a period, the number of valence shells decreases meaning the atom is getting smaller which in turn means the proton...
Thu Nov 07, 2019 3:32 pm
Forum: Lewis Structures
Topic: When to draw Resonance Structures
Replies: 14
Views: 176

Re: When to draw Resonance Structures

How do we know when a molecule has resonance? A molecule has resonance when it has a bond that can be drawn in a different place and not alter the overall formal charge of the atom or molecule itself. For example, if you have a carbon single bonded to two oxygen and single bonded to another, you ca...
Sun Nov 03, 2019 2:11 am
Forum: Electronegativity
Topic: Electronegativity
Replies: 9
Views: 115

Electronegativity

When drawing lewis structures will we be given the electronegativity table to determine which atom will be the central atom?
Sun Nov 03, 2019 2:06 am
Forum: Lewis Structures
Topic: Exceptions to the octet rule
Replies: 3
Views: 60

Re: Exceptions to the octet rule

How do we know how many valence electrons an element with an expanded octet has? How are lone pairs shown in a lewis dot structure?
Sun Nov 03, 2019 1:46 am
Forum: Properties of Light
Topic: Equations
Replies: 4
Views: 81

Re: Equations

The reference sheet will most likely be like the one given on the first test. It did include these equations, but did not give the name of each equation.
Sun Nov 03, 2019 1:28 am
Forum: Lewis Structures
Topic: central atom
Replies: 16
Views: 1494

Re: central atom

Arianna Perea 3H wrote:why is the central atom the one with the least electronegativity?

The least electronegative elements are in the center of lewis structures because an atom in the central position shares more of its electrons than does an atom on the sides of the central atom or the terminal position.
Sun Nov 03, 2019 1:10 am
Forum: Dipole Moments
Topic: Definition
Replies: 5
Views: 104

Re: Definition

Dipole Moment refers to the momentary positive or negative charge which exists on an atom when the electrons are temporarily located at a given position on it. It is represented by an arrow placed between the partial positive and partial negative charges on two atoms, with the arrow pointing toward...
Sat Oct 26, 2019 7:30 pm
Forum: Lewis Structures
Topic: Lewis Structure
Replies: 5
Views: 87

Re: Lewis Structure

The least electronegative elements are in the center of lewis structures because an atom in the central position shares more of its electrons than does a terminal atom such as Hydrogen which is never found in the center.
Sat Oct 26, 2019 7:24 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ionization Energy
Replies: 4
Views: 47

Ionization Energy

When talking about ionization energy, why is it that it's harder to remove a 2nd electron from an atom and does this mean that there are multiple ionization energies for an element?
Sat Oct 26, 2019 6:54 pm
Forum: Ionic & Covalent Bonds
Topic: Resonance (all bonds are a hybrid of different bonds)
Replies: 10
Views: 158

Re: Resonance (all bonds are a hybrid of different bonds)

How can you tell if a compound has resonance and do all resonance forms need to be drawn when being asked for a lewis dot diagram?
Sat Oct 26, 2019 6:43 pm
Forum: Ionic & Covalent Bonds
Topic: Does the Octet Rule apply to Boron?
Replies: 14
Views: 153

Re: Does the Octet Rule apply to Boron?

Both Boron and Aluminum are both satisfied with six valence electrons instead of 8 as implied by the octet rule.
Sat Oct 26, 2019 6:13 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic and Covalent Bonds
Replies: 4
Views: 46

Ionic and Covalent Bonds

How do you know whether or not two elements share a covalent or ionic bond and why?
Sun Oct 20, 2019 12:54 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: quantum number n, l, m
Replies: 13
Views: 157

Re: quantum number n, l, m

n represents the principal quantum number which is the shell that the electron is located on. l is the angular momentum quantum number and it describes the shape of the orbital. It can either be an s orbital, p orbital, d orbital, or f orbital. m is the magnetic quantum number and it tells you the ...
Sun Oct 20, 2019 12:42 pm
Forum: Properties of Electrons
Topic: Wave-like and particle-like properties
Replies: 7
Views: 88

Re: Wave-like and particle-like properties

All things have wave-particle duality, but due to the behavior of large objects, they act more as particles than waves. Things that are quantized have behaviors that must consider both the wave properties and particle properties such as electrons.
Sun Oct 20, 2019 1:35 am
Forum: Photoelectric Effect
Topic: The Rydberg Formula and the Hydrogen Atomic Spectrum
Replies: 4
Views: 103

The Rydberg Formula and the Hydrogen Atomic Spectrum

I'm still confused as to if Rydberg's formula can work for only for the hydrogen emission spectrum? Why or Why not?
Sun Oct 20, 2019 12:21 am
Forum: *Shrodinger Equation
Topic: wavefunctions & orbitals relationship?
Replies: 5
Views: 192

Re: wavefunctions & orbitals relationship?

Due to the fact that orbitals act as waves, a wave function is a mathematical function that shows the wave-like behavior of electron(s) in an atom and the probable location to finding an electron in a specific region around the nucleus of an atom.
Sun Oct 20, 2019 12:15 am
Forum: Properties of Electrons
Topic: Energy increasing
Replies: 7
Views: 139

Re: Energy increasing

Increasing in energy levels refers to an electron within an atom when they absorb enough energy to move from a lower to higher energy level.
Sat Oct 12, 2019 2:54 am
Forum: Properties of Electrons
Topic: Wave properties
Replies: 5
Views: 47

Re: Wave properties

After determining the wavelength (m) using De Broglie's wave equation use the answer to determine if it's below any # x 10^-15 in scientific notation, if it is then it's considered to have wavelike properties and if it's above that it does not have wavelike properties. The smaller the wavelength, th...
Sat Oct 12, 2019 2:22 am
Forum: Properties of Electrons
Topic: Electron After Excited State
Replies: 7
Views: 114

Re: Electron After Excited State

When an electron gets excited, it absorbs energy and jumps to a higher energy level. An excited electron can release energy in the form of a photon and "fall" to a lower state due to the fact that an excited electron is unstable and rearranges itself to return to its lower energy state.
Sat Oct 12, 2019 2:00 am
Forum: Properties of Electrons
Topic: Mass of Electron in De Broglie Equation
Replies: 4
Views: 66

Mass of Electron in De Broglie Equation

In one example given in lecture, we are asked to calculate the De Broglie wavelength of an electron traveling at a specific velocity (m.s^-1) and the question given doesn't include the mass (kg) of an electron. Are we suppose to already know or memorize the mass of an electron or is the information ...