Search found 102 matches
- Thu Mar 12, 2020 9:51 am
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: kinetics
- Replies: 9
- Views: 623
Re: kinetics
If a catalyst is added to lower activation energy, the reaction will be able to take place.
- Thu Mar 12, 2020 9:50 am
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: kinetics vs. thermodynamics
- Replies: 23
- Views: 1204
kinetics vs. thermodynamics
What does it mean when kinetics rather than thermodynamics is controlling a reaction?
- Thu Mar 12, 2020 9:37 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Concentration cell
- Replies: 8
- Views: 578
Re: Concentration cell
A concentration cell has an anode and cathode made up of the same substance whereas in a galvanic cell, the anode and cathode are different substances.
- Thu Mar 12, 2020 9:36 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Notation Layout
- Replies: 7
- Views: 403
Re: Cell Notation Layout
an example is: Zn(s) | Zn2+(aq) || Cu2+(aq) | Cu(s),
where the anode is on the left of the salt bridge and the cathode is on the right
where the anode is on the left of the salt bridge and the cathode is on the right
- Thu Mar 12, 2020 9:34 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: salt bridge
- Replies: 11
- Views: 613
Re: salt bridge
The purpose of the salt bridge is to prevent charge buildup; it is made up of a concentrated aqueous salt solution in an inverted, U shaped tube that allows the flow of ions that don't affect the cell reaction.
- Thu Mar 12, 2020 9:31 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagrams
- Replies: 13
- Views: 833
Re: Cell Diagrams
When there's no solid metals present and it's only aqueous components, then you would add an inert metal.
- Thu Mar 12, 2020 9:30 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Change in Ecell
- Replies: 5
- Views: 318
Re: Change in Ecell
Increasing the size of the metal does not cause a change in Ecell.
- Thu Mar 12, 2020 9:27 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: E cell
- Replies: 9
- Views: 597
Re: E cell
E standard cell is the standard cell potential under standard conditions, such as all solutes present at 25 degrees C, 1 mol/L; all gases at 1 bar. Ecell would be cell potential under non-standard conditions.
- Thu Mar 12, 2020 9:24 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: calculating Q
- Replies: 12
- Views: 746
Re: calculating Q
Q = [products]/[reactants] so it would be [anode]/[cathode]
- Thu Mar 12, 2020 9:21 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: electrolysis
- Replies: 3
- Views: 297
Re: electrolysis
The approach is different since the arrangement of components in electrolytic cells is not the same as in galvanic cells. With electrolytic cells, the two electrodes usually share the same compartment.
- Mon Mar 02, 2020 1:51 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Moles in nernst
- Replies: 4
- Views: 300
Re: Moles in nernst
n would be the moles of electrons being transferred
- Mon Mar 02, 2020 1:50 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation Use
- Replies: 3
- Views: 312
Re: Nernst Equation Use
The Nernst equation is used to determine the direction of electron transfer under nonstandard conditions since cell potential depends on the concentration of products to reactants.
- Mon Mar 02, 2020 1:32 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Voltage
- Replies: 6
- Views: 407
Re: Voltage
Using a positive sign helps to clearly indicate a positive charge of voltage/a positive "potential difference"
- Mon Mar 02, 2020 1:21 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electrolytes vs electrodes
- Replies: 5
- Views: 311
Re: Electrolytes vs electrodes
Electrodes are metallic conductors that are in contact with but separated by electrolytes. Electrolytes are aqueous solutions of ionic compounds (basically ions) that act as a medium for the current flow.
- Mon Mar 02, 2020 1:09 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst equation and K
- Replies: 3
- Views: 301
Re: Nernst equation and K
K is used for redox reactions at equilibrium since K is the equilibrium constant. Electron flow does stop at equilibrium since the concentration changes to the point where Q = K and the cell potential becomes 0.
- Mon Mar 02, 2020 1:01 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Degree symbol
- Replies: 10
- Views: 970
Re: Degree symbol
The symbol indicates that the value of the variable is when the variable is at standard conditions, like at 1 ATM or at 298K.
- Mon Mar 02, 2020 12:49 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: N value
- Replies: 7
- Views: 446
Re: N value
Yes, 2 would be n since n is the number of electrons being transferred, but make sure your half-reactions are balanced!
- Mon Mar 02, 2020 12:45 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Work and Cell Potential Relationship
- Replies: 3
- Views: 245
Re: Work and Cell Potential Relationship
The equation that represents the relationship between work and cell potential is: wMAX = - n F E. wMAX is the work done, which is also equal to ∆G, the change in Gibbs free energy.
- Mon Mar 02, 2020 12:33 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Free Energy and Cell Potential Relationship
- Replies: 3
- Views: 260
Re: Free Energy and Cell Potential Relationship
Free energy and cell potential are related through the equation ∆G = - n F E, where ∆G is the change in Gibbs free energy, n is the number of electrons being transferred, F is Faraday's constant, and E is the cell potential.
- Mon Mar 02, 2020 12:28 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n in Equation
- Replies: 6
- Views: 441
Re: n in Equation
In the equation, n is the number of electrons in moles that is being transferred.
- Tue Feb 18, 2020 2:42 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: galvanic cell structure
- Replies: 8
- Views: 372
galvanic cell structure
Why does oxidation take place at the anode and why does reduction take place at the cathode?
- Tue Feb 18, 2020 2:35 pm
- Forum: Balancing Redox Reactions
- Topic: Reduction vs. oxidation
- Replies: 29
- Views: 1147
Re: Reduction vs. oxidation
reduction: gain of electrons, charge becomes more negative
oxidation: loss of electrons, charge becomes more positive
I don't think it has to do with proton transfer since it has to do with a gain or loss of electrons.
oxidation: loss of electrons, charge becomes more positive
I don't think it has to do with proton transfer since it has to do with a gain or loss of electrons.
- Tue Feb 18, 2020 2:28 pm
- Forum: Balancing Redox Reactions
- Topic: Whats the difference between oxidizing agent and oxiadation
- Replies: 6
- Views: 322
Re: Whats the difference between oxidizing agent and oxiadation
oxidation: loss of electrons
oxidizing agent: causes oxidation and gets reduced in the process
oxidizing agent: causes oxidation and gets reduced in the process
- Tue Feb 18, 2020 2:13 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing and Adding together Half-Rxns
- Replies: 6
- Views: 310
Re: Balancing and Adding together Half-Rxns
Since oxidation and reduction reactions happen together, the number of electrons released by oxidation needs to be the same as the number of electrons used in reduction due to the fact that in chemical reactions, electrons are neither created nor destroyed.
- Tue Feb 18, 2020 2:08 pm
- Forum: Balancing Redox Reactions
- Topic: Free Electrons?
- Replies: 3
- Views: 178
Re: Free Electrons?
^^ Like what they said, an oxidation half-reaction and reduction half-reaction are part of an overall redox reaction. Writing the half-reaction is a conceptual way of showing just the oxidation part of the redox reaction or the reduction part. The electron is not actually free, it's in transit unlik...
- Sun Feb 09, 2020 6:46 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Intensive vs Extensive
- Replies: 7
- Views: 321
Re: Intensive vs Extensive
Intensive properties are properties independent of the quantity of the substance. One example is specific heat capacity since it is specified/normalized to 1 gram of a substance. Extensive properties do depend on the amount of a substance, like heat capacity.
- Sun Feb 09, 2020 6:37 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Thermodynamic system
- Replies: 3
- Views: 214
Re: Thermodynamic system
In an open system, both matter and energy can be exchanged with the system and surroundings.
- Sun Feb 09, 2020 6:29 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: difference between molar entropies?
- Replies: 6
- Views: 334
difference between molar entropies?
Why does lead have a higher molar entropy than carbon?
- Sun Feb 09, 2020 5:47 pm
- Forum: Phase Changes & Related Calculations
- Topic: relationship between heat capacity and heating curve
- Replies: 6
- Views: 252
Re: relationship between heat capacity and heating curve
For a heating curve, q is on the x axis and the temperature is on the y axis. When you have a steep slope, this means that for smaller increases in q (heat), there are larger increases in temperature, which correlates to a lower heat capacity. When you have a more flat slope, for larger increases in...
- Sun Feb 09, 2020 5:39 pm
- Forum: Phase Changes & Related Calculations
- Topic: Heating Curve Phase Changes
- Replies: 11
- Views: 590
Re: Heating Curve Phase Changes
The heat supplied to cause a substance's phase change does not actually change the heat of the substance.
- Sun Feb 02, 2020 10:55 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: qp = ΔH?
- Replies: 5
- Views: 320
qp = ΔH?
When does qp = ΔH?
- Sun Feb 02, 2020 10:53 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Forming bonds
- Replies: 8
- Views: 186
Re: Forming bonds
When bonds form, they become more stable, which means they release energy.
- Sun Feb 02, 2020 10:35 pm
- Forum: Phase Changes & Related Calculations
- Topic: phase changes, temperature constant?
- Replies: 11
- Views: 584
phase changes, temperature constant?
During phase transition, why does the temperature of the sample remains constant even though heat is being supplied?
- Sun Feb 02, 2020 10:20 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy of Rxn
- Replies: 9
- Views: 394
Re: Enthalpy of Rxn
You would multiply so that the moles cancel out and you are left with the units kJ.
- Sun Feb 02, 2020 10:16 pm
- Forum: Phase Changes & Related Calculations
- Topic: calorimeter vs bomb calorimeter
- Replies: 1
- Views: 117
calorimeter vs bomb calorimeter
Is a regular calorimeter also an insulated system like a bomb calorimeter or is it a closed system?
- Thu Jan 30, 2020 12:08 am
- Forum: Phase Changes & Related Calculations
- Topic: 4A. 1 Identifying open and closed system
- Replies: 11
- Views: 2654
Re: 4A. 1 Identifying open and closed system
D is an open system because it has interactions externally with the environment, it is releasing energy into the air. C is a closed system because the bomb calorimeter is designed to keep gases in so no gas is released to interact with the environment. Why is C a closed system? Wouldn't a bomb calo...
- Sun Jan 26, 2020 8:24 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: solvent
- Replies: 10
- Views: 388
Re: solvent
Solvents tend to be liquid (l), thus won't be included in equilibrium constant calculations. Additionally, solids won't be included as well, due to their activities being equal to 1. Aqueous solutions and gases are always included.
- Sun Jan 26, 2020 8:22 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Energy of the reactants
- Replies: 6
- Views: 303
Re: Energy of the reactants
The reaction is endothermic. Energy has to have been absorbed in order for the products to have a higher energy than the reactants.
- Thu Jan 23, 2020 3:17 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5% rule
- Replies: 13
- Views: 587
Re: 5% rule
I believe when K is less than 10^-3, you can approximate with the 5% rule.
- Thu Jan 23, 2020 3:15 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ice table
- Replies: 13
- Views: 543
Re: ice table
No because you don't need to include them in calculating equilibrium constants.
- Thu Jan 23, 2020 3:14 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 6B.11
- Replies: 1
- Views: 55
6B.11
A student added solid Na2O to a volumetric flask of volume 200.0 mL, which was then filled with water, resulting in 200.0 mL of NaOH solution. Then 5.00 mL of the solution was transferred to another volumetric flask and diluted to 500.0 mL. The pH of the diluted solution is 13.25. (a) What is the mo...
- Sun Jan 19, 2020 12:43 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 5% rule
- Replies: 10
- Views: 442
Re: 5% rule
When calculating the percent ionization and it is less than 5%, it confirms that the approximation of x in the ICE table is okay and the use of the quadratic formula is not necessary.
- Sun Jan 19, 2020 12:30 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Difference between K and Q?
- Replies: 11
- Views: 523
Re: Difference between K and Q?
Q is calculated the same was as K. However, K is the equilibrium constant while Q is the reaction quotient at any time during the reaction. You compare Q to K in order to find out whether the reaction is at equilibrium or not. When Q<K, the forward reaction is favored since the concentration of reac...
- Sun Jan 19, 2020 12:19 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: % protonated
- Replies: 3
- Views: 96
Re: % protonated
When finding the percentage protonated, whatever is receiving a proton is being protonated. A base accepts protons. You'll need to know if it is protonated depending on what the question is asking.
- Sun Jan 19, 2020 12:19 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ka and Kb
- Replies: 3
- Views: 82
Re: Ka and Kb
Ka uses the concentration of hydronium ions, so you would usually use it when dealing with acids. Kb uses the concentration of hydroxide ions, so you would usually use it when dealing with bases.
- Sat Jan 18, 2020 11:13 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Constant Units
- Replies: 4
- Views: 471
Re: Equilibrium Constant Units
It is unitless because in the calculation of the equilibrium constant, you're using the activities of the reactants and products, as someone else said. Section 5G.2 in the textbook pretty much explains why it's unitless: "Thus, for a substance J that forms an ideal solution, the partial pressur...
- Wed Jan 08, 2020 9:35 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Finding K without aq
- Replies: 4
- Views: 145
Re: Finding K without aq
K would be 1 since the activities of solids and liquids are all 1.
- Wed Jan 08, 2020 9:33 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Constant
- Replies: 8
- Views: 380
Re: Equilibrium Constant
You use Kc when given molar concentrations of reactants and products. You use Kp when dealing with the partial pressures of reactants and products, which are in the gas phase.
- Wed Jan 08, 2020 9:31 pm
- Forum: Ideal Gases
- Topic: K and Q
- Replies: 13
- Views: 330
Re: K and Q
You use K when calculating the equilibrium constant when the reaction is at equilibrium. Q is the reaction quotient used to determine whether a reaction not at equilibrium will favor reactants or products.
- Wed Jan 08, 2020 9:23 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Writing K expression with or without aq?
- Replies: 5
- Views: 291
Re: Writing K expression with or without aq?
Reactants and products that are in the aqueous state are included. As the other person said, it's pretty much used with Kc.
- Wed Jan 08, 2020 9:13 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Small K value and Large K value
- Replies: 10
- Views: 697
Re: Small K value and Large K value
In lecture, Lavelle said that if the value is between the two limits neither the reactant nor the product is favored and it is in a sort of intermediate state. Does that mean that we most likely won't be asked a question on whether the reactants or products are favored if the K value falls between ...
- Sat Dec 07, 2019 4:16 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: weak bases produce acidic solutions?
- Replies: 3
- Views: 311
weak bases produce acidic solutions?
Why do salts of weak bases produce acidic solutions? Why do salts of weak acids produce basic
solutions?
solutions?
- Sat Dec 07, 2019 4:08 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: weak acids have higher pH values?
- Replies: 1
- Views: 65
weak acids have higher pH values?
Why do solutions of weak acids have higher pH values than solutions of strong acids at the same concentration? Is it simply because solutions of weak acids have less hydronium ions present than solutions of strong acids?
- Sat Dec 07, 2019 3:39 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: pH and hydronium and hydroxide ion concentrations
- Replies: 2
- Views: 216
pH and hydronium and hydroxide ion concentrations
How is a solution's pH related to hydronium ion and hydroxide ion concentrations?
- Sat Dec 07, 2019 3:32 pm
- Forum: Amphoteric Compounds
- Topic: amphiprotic vs. amphoteric
- Replies: 1
- Views: 187
amphiprotic vs. amphoteric
What is the difference between amphiprotic and amphoteric?
- Fri Nov 29, 2019 8:41 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligands
- Replies: 6
- Views: 424
Re: Ligands
Ligands are considered Lewis bases since they are electron pair donors.
- Fri Nov 29, 2019 8:39 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: coordination number
- Replies: 8
- Views: 416
Re: coordination number
Coordination number is basically the number of bonds the central atom has with ligands.
- Fri Nov 29, 2019 8:01 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Shapes
- Replies: 4
- Views: 308
Re: Shapes
Coordination compounds with 6 ligands are octahedral complexes, with 4 ligands are either tetrahedral or square planar, and with 2 ligands are linear.
- Fri Nov 29, 2019 7:58 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Lewis bases vs. ligands
- Replies: 3
- Views: 164
Re: Lewis bases vs. ligands
A Lewis base is an electron pair donor, so it can be an atom or molecule that donates an electron pair.
- Fri Nov 29, 2019 7:44 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligands
- Replies: 3
- Views: 253
Re: Ligands
Ligands must have one or more lone pairs. When it has one lone pair of electrons, it is mono-dentate and binds with the central metal atom. When it has more than one lone pair, it can occupy more than one binding site at once and this can be labeled as chelating.
- Sun Nov 24, 2019 11:27 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Complexes
- Replies: 2
- Views: 192
Re: Complexes
A complex always consists of central metal atom/ion attached to other molecules and ions through coordinate covalent bonds.
- Sun Nov 24, 2019 11:26 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Cis vs Trans
- Replies: 22
- Views: 1655
Re: Cis vs Trans
Cis molecules are polar since the bonded atoms that are the same are next to each other. Trans molecules are nonpolar since the bonded atoms that are same are located opposite each other.
- Sun Nov 24, 2019 11:21 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination Sphere
- Replies: 5
- Views: 406
Re: Coordination Sphere
The coordination sphere consists of the ligands directly attached to central transitional metal ion.
- Sun Nov 24, 2019 11:14 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: coordination sphere
- Replies: 3
- Views: 221
Re: coordination sphere
The coordination sphere is made up of the ligands directly attached to the central transition metal cation.
- Sun Nov 24, 2019 11:12 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Difference Between TM complex and organometallic complex
- Replies: 1
- Views: 81
Difference Between TM complex and organometallic complex
What is the difference between a transition metal complex and an organometallic complex?
- Sun Nov 24, 2019 10:41 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Transition Metals
- Replies: 7
- Views: 447
Re: Transition Metals
Yes. A striking property of d-block elements is that they are able to form coordination compounds.
- Fri Nov 15, 2019 11:23 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: why are double bonds equally weighted as single ones when drawing models?
- Replies: 10
- Views: 1951
Re: why are double bonds equally weighted as single ones when drawing models?
Jorge Ramirez_4H wrote:Does weight not affect angles?
No because the bond angles are formed from the repulsion between lone pairs and bonding electrons.
- Fri Nov 15, 2019 11:21 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: why are double bonds equally weighted as single ones when drawing models?
- Replies: 10
- Views: 1951
Re: why are double bonds equally weighted as single ones when drawing models?
Single, double, triple bonds are all considered single regions of electron density in the VSEPR model.
- Fri Nov 15, 2019 11:19 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lewis Structures & VSEPR
- Replies: 9
- Views: 443
Re: Lewis Structures & VSEPR
It's not necessary but it's always helpful so that you can see the locations of bonding electrons and lone pairs then use the VSEPR model and determine the structure.
- Fri Nov 15, 2019 11:12 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: structure ?
- Replies: 8
- Views: 432
Re: structure ?
A molecule will have linear structure when the central atom has no lone pairs. This is because the bonding pairs will lie on opposite sides of the central atom to be far apart. Examples are H2O and BeCl2. It helps to draw Lewis structures.
- Thu Nov 14, 2019 4:34 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Do we need to know bent structures?
- Replies: 5
- Views: 219
Re: Do we need to know bent structures?
How do we tell if the structure is going to be bent versus linear? BeCl2 has no lone pairs on the central atom, beryllium. The two bonding pairs are on opposite sides of the Be atom to be far away from each other, so the structure is linear. The same goes for CO2; the central atom, carbon, has no l...
- Thu Nov 14, 2019 4:03 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Do we need to know bent structures?
- Replies: 5
- Views: 219
Re: Do we need to know bent structures?
Yes, molecules with bent/angular structures are something that we went over in class. An example is H2O.
- Sat Nov 09, 2019 10:20 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: Instantaneous dipole moment
- Replies: 5
- Views: 153
Re: Instantaneous dipole moment
I don't think there's a specific length of time; it's simply an instant since there's always fluctuations with electron distribution.
- Sat Nov 09, 2019 10:16 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: Dispersion Force
- Replies: 3
- Views: 194
Re: Dispersion Force
Dispersion forces act between all atoms and molecules, not within one atom, because they are attractive interactions.
- Sat Nov 09, 2019 10:13 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: Ion-Dipole Forces
- Replies: 4
- Views: 214
Re: Ion-Dipole Forces
An ion-dipole force occurs between an ion and a dipole/the partial charges of polar molecules. The attraction between a Cl anion and the polar H2O molecule is an example of this force.
- Sat Nov 09, 2019 10:09 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: London Dispersion Forces VS. Induced Dipole - Induced Dipole
- Replies: 2
- Views: 52
Re: London Dispersion Forces VS. Induced Dipole - Induced Dipole
London dispersion forces and induced dipole-induced dipole can be used interchangeably. Electron distribution in atoms and molecules fluctuates which results in fluctuating dipoles and the interactions are always present and attractive.
- Sat Nov 09, 2019 9:19 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: what is electron distortion?
- Replies: 3
- Views: 145
what is electron distortion?
I know that electrons in atoms or molecules can cause electron distortion in nearby atoms or molecules but what exactly is electron distortion? Why do ions with high electron distortion also have high polarizing power?
- Sun Nov 03, 2019 7:31 pm
- Forum: Coordinate Covalent Bonds
- Topic: coordinate covalent bond
- Replies: 7
- Views: 939
Re: coordinate covalent bond
It's a bond where both electrons come from one atom, completing the octet of an atom existing in a compound with an incomplete one. The example provided in class and in the textbook was that of boron trifluoride BF3, and boron has only six valence electrons. Its octet is completed when it forms a co...
- Sun Nov 03, 2019 7:01 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic and Covalent
- Replies: 5
- Views: 221
Re: Ionic and Covalent
In ionic bonds, there's a transfer of electrons from a metal to nonmetal atom. In covalent bonds, non-metals share electrons. But, many bonds have both ionic and covalent characteristics. Roughly, an electronegativity difference between atoms that is greater than 2 indicates an ionic bond, an electr...
- Sun Nov 03, 2019 6:57 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic and Covalent Characteristics
- Replies: 3
- Views: 178
Re: Ionic and Covalent Characteristics
A covalent bond has ionic properties when there's unequal charges/charge asymmetry since the electron pair in the bond may not be equally shared. The extent of the ionic properties depends on the electronegativity of each bonding atom, like what the other person said. Atoms with high electronegativi...
- Sun Nov 03, 2019 12:21 am
- Forum: Lewis Structures
- Topic: Octet Rule
- Replies: 7
- Views: 192
Re: Octet Rule
Okay, then let's say it's a different element like Carbon. Would it still be following the rule? Lewis structures show how atoms are bonded together, and atoms bond together to achieve an octet so atoms in a Lewis dot structure should be following the octet rule. Also, I think it is more accurate t...
- Sun Oct 27, 2019 6:56 pm
- Forum: Lewis Structures
- Topic: Clarification
- Replies: 6
- Views: 204
Re: Clarification
Obtaining a formal charge of 0 is more important since it means that although the octet rule is reached, the atoms have exactly a half-share in a pair of bonding electrons.
- Sun Oct 27, 2019 6:45 pm
- Forum: Resonance Structures
- Topic: Determining Resonance Structures
- Replies: 6
- Views: 267
Re: Determining Resonance Structures
I thought that resonance structures were "ideal" when the formal charges of the atoms were equal to 0? Or close to that value in some cases. Wait yes, the "ideal" structure is as you said, when the formal charges of the atoms are at 0, since the formal charges of atoms in a mole...
- Sun Oct 27, 2019 6:34 pm
- Forum: Lewis Structures
- Topic: Octet Rule
- Replies: 7
- Views: 192
Re: Octet Rule
Helium probably wouldn't bond with other elements because it is already stable as a noble gas. Noble gasses are known not to react with other elements. Okay, then let's say it's a different element like Carbon. Would it still be following the rule? Lewis structures show how atoms are bonded togethe...
- Sun Oct 27, 2019 6:25 pm
- Forum: Resonance Structures
- Topic: Determining Resonance Structures
- Replies: 6
- Views: 267
Re: Determining Resonance Structures
Polyatomic molecules have resonance when it has Lewis structures with multiple bonds that can be placed in different but equivalent locations. The real structure is a blend of the polyatomic molecule's different Lewis structures, which is resonance.
- Sun Oct 27, 2019 6:17 pm
- Forum: Ionic & Covalent Bonds
- Topic: Writing Electron Configurations for an Ion
- Replies: 6
- Views: 278
Re: Writing Electron Configurations for an Ion
Yes because an anion has a negative charge and a cation has a positive charge. Nonmetal atoms form anions with an octet corresponding to the configuration of the following noble gas.
- Sun Oct 20, 2019 12:25 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Hund's rule and Pauli Exclusion Principle
- Replies: 14
- Views: 773
Re: Hund's rule and Pauli Exclusion Principle
Both are used to determine ground state electron configuration. With the Pauli Exclusion Principle, electrons in the same orbital must have different spins. With Hund's rule, electrons must occupy different orbitals singularly, with the same spin before doubling up.
- Sun Oct 20, 2019 12:11 am
- Forum: *Shrodinger Equation
- Topic: Schrodinger for exam
- Replies: 20
- Views: 800
Re: Schrodinger for exam
I would assume so since Professor Lavelle's outline for The Quantum World lists that we should understand the relationship between Schrodinger's Equation, wave functions, and orbitals.
- Sun Oct 20, 2019 12:07 am
- Forum: *Shrodinger Equation
- Topic: Wave functions
- Replies: 9
- Views: 343
Re: Wave functions
Wave functions represent the probability of finding the position of an electron in an atom. They are used to describe an electron, which has wavelike properties and indeterminate momentum/position, in an atom.
- Sat Oct 19, 2019 11:57 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic Spectra Wave Model or Particle Model?
- Replies: 2
- Views: 229
Re: Atomic Spectra Wave Model or Particle Model?
Atomic spectra shows that light has particle-like properties. Electrons in atoms and molecules absorb/emit discrete packets of energy. Spectral lines result from a transition between two energy levels, and the difference in energy is emitted as a photon.
- Sat Oct 19, 2019 11:29 pm
- Forum: *Shrodinger Equation
- Topic: wavefunctions & orbitals relationship?
- Replies: 5
- Views: 279
wavefunctions & orbitals relationship?
I am still a bit confused on the concept of wavefunctions. From my understanding, wavefunctions represent the varying positions of particles since they have wave-like properties and do not have precise trajectories. How does this relate to orbitals?
- Sat Oct 12, 2019 5:23 pm
- Forum: Photoelectric Effect
- Topic: How much energy to remove one electron?
- Replies: 8
- Views: 233
Re: How much energy to remove one electron?
Leila_4E wrote:What is the work function?
The work function is the energy needed to remove an electron from a metal.
- Sat Oct 12, 2019 5:18 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect
- Replies: 3
- Views: 147
Re: Photoelectric Effect
If that is true ( if excess energy is used to emit electrons and since the electrons are moving, the excess energy is basically manifested as the kinetic energy of the electron) then what would be the kinetic energy when the threshold energy is met exactly? If I am not mistaken, the kinetic energy ...
- Sat Oct 12, 2019 4:49 pm
- Forum: Photoelectric Effect
- Topic: work function clarification
- Replies: 4
- Views: 138
work function clarification
Just to clarify, the work function of a metal is the same as the threshold energy, the minimum amount of energy required to eject electrons from a metal surface?
- Sat Oct 12, 2019 4:41 pm
- Forum: Properties of Light
- Topic: UV photons vs. photons of visible light
- Replies: 2
- Views: 66
UV photons vs. photons of visible light
What causes ultraviolet photons to be more energetic than photons of visible light? Is it simply due to the fact that ultraviolet light has higher frequencies and shorter wavelengths than visible light?
- Sat Oct 12, 2019 4:22 pm
- Forum: Properties of Light
- Topic: Light Intensity
- Replies: 6
- Views: 177
Re: Light Intensity
One thinking point in the texbook asked why ultraviolet radiation is much more harmful to living tissue than infared radiation... I was wondnerinf if someone could explain the answer. I think this is because ultraviolet radiation has higher frequency and shorter wavelengths than infrared radiation,...
- Thu Oct 03, 2019 11:43 pm
- Forum: SI Units, Unit Conversions
- Topic: Sig Figs: follow the book or follow Sig Fig rules?
- Replies: 3
- Views: 184
Re: Sig Figs: follow the book or follow Sig Fig rules?
I think it would be best to follow sig fig rules, but like what another person asked, which problems in the solution manual ignored sig fig rules?
- Thu Oct 03, 2019 9:38 pm
- Forum: Empirical & Molecular Formulas
- Topic: Clarification
- Replies: 6
- Views: 408
Re: Clarification
It is possible to go from molecular to empirical. You would just need to get each of the subscripts in the formula and change it so they are at the simplest ratio and still keeping whole numbers. I don't think we would really need to do this though. I think you meant to say that the coefficients in...
- Thu Oct 03, 2019 9:34 pm
- Forum: Balancing Chemical Reactions
- Topic: Fractioned Chemical Equations?
- Replies: 5
- Views: 295
Re: Fractioned Chemical Equations?
Yes, it's better and more practical to change fractional coefficients in chemical equations into whole numbers. With whole number coefficients, you could clearly see mole ratios between reactants and products.
- Thu Oct 03, 2019 9:20 pm
- Forum: SI Units, Unit Conversions
- Topic: which unit to use
- Replies: 9
- Views: 494
Re: which unit to use
I think the units should be consistent with what the problem asks you to solve for.