Search found 104 matches
- Sun Mar 15, 2020 7:54 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: pH of acids
- Replies: 13
- Views: 1080
Re: pH of acids
Strong acids have a higher percent ionization than weak acids, so there is more H30 present in solutions with strong acids, causing them to have a lower pH.
- Sun Mar 15, 2020 7:53 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: R
- Replies: 3
- Views: 331
Re: R
You use the 8.314 value because it allows you to cancel out the units properly.
- Sun Mar 15, 2020 7:52 am
- Forum: Phase Changes & Related Calculations
- Topic: state functions
- Replies: 13
- Views: 1412
Re: state functions
State functions are functions that only consider the initial and final states, not the path that is taken to obtain those states. An example of a state property is displacement, whereas the non-state property would be the total distance traveled.
- Sun Mar 15, 2020 7:50 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Extensive and Intensive Properties
- Replies: 12
- Views: 1055
Re: Extensive and Intensive Properties
Extensive properties are independent of the amount of a substance, intensive properties rely on the mass (or amount)
- Sun Mar 15, 2020 7:47 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: platinum
- Replies: 4
- Views: 374
Re: platinum
Whichever side does not have an electrode uses platinum as its electrode
- Mon Mar 09, 2020 12:11 am
- Forum: Balancing Redox Reactions
- Topic: Determining the oxidizer and reducer
- Replies: 10
- Views: 746
Re: Determining the oxidizer and reducer
The reaction with the more positive Ecell is has a higher oxidizing power, the more negative has a higher reducing power.
- Mon Mar 09, 2020 12:07 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: galvanic vs electrolytic
- Replies: 12
- Views: 909
Re: galvanic vs electrolytic
Galvanic cells are cells that use spontaneous reactions. Electrolytic cells use non-spontaneous reactions.
- Mon Mar 09, 2020 12:05 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: gibbs free energy
- Replies: 15
- Views: 870
Re: gibbs free energy
The Gibbs free energy is the energy available to do work.
- Mon Mar 09, 2020 12:03 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n in NFE
- Replies: 64
- Views: 3869
Re: n in NFE
n is the number of moles of electrons that are transferred.
- Mon Mar 09, 2020 12:02 am
- Forum: Balancing Redox Reactions
- Topic: Half rxns
- Replies: 27
- Views: 1487
Re: Half rxns
When the solution is acidic, you balance the hydrogen ions by adding an H+ to the other side. When the solution is basic, you balance the hydrogen by adding an H20 to the side that needs the hydrogen and a OH- on the other side so that the side with the H20 has a net higher number of hydrogens.
- Sun Mar 01, 2020 9:58 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Stablility
- Replies: 3
- Views: 279
Re: Stablility
The lower the Gibbs free energy of a reaction is, the more stable its products are.
- Sun Mar 01, 2020 9:57 pm
- Forum: Balancing Redox Reactions
- Topic: OH and H
- Replies: 8
- Views: 497
Re: OH and H
As long as the equation is balanced, they can be on either side of the equation.
- Sun Mar 01, 2020 9:50 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: identifying cathode/anode
- Replies: 4
- Views: 383
Re: identifying cathode/anode
The cathode is usually the one being reduced and the another is the one that is being oxidized. Because of this, the scenario you're describing is not possible.
- Sun Mar 01, 2020 9:49 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: cell potential
- Replies: 15
- Views: 830
Re: cell potential
delta G=-nFE, so if there is a positive cell potential (E) then delta G is negative, making it a spontaneous reaction.
- Thu Feb 27, 2020 4:53 pm
- Forum: Van't Hoff Equation
- Topic: HW 11.83
- Replies: 4
- Views: 1083
Re: HW 11.83
Can we also use the ln(k2/k1)=-delta H standard/R[1/t1 -1/t2] to solve this problem or do we have to find the separate standard G to find the values of K?
- Sun Feb 23, 2020 8:32 pm
- Forum: Balancing Redox Reactions
- Topic: Polyatomic Ions
- Replies: 4
- Views: 320
Re: Polyatomic Ions
In the past Lavelle has usually given the charges of the ions, but I think it's helpful to know some of them just in case.
- Sun Feb 23, 2020 8:29 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Half reactions
- Replies: 13
- Views: 771
Re: Half reactions
A half reaction is a reaction that displays either the oxidation or the reduction in a redox reaction.
- Sun Feb 23, 2020 8:27 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cathode vs Anode
- Replies: 11
- Views: 947
Re: Cathode vs Anode
The cathode is the reaction that is being reduced, and the anode is the reaction that is being oxidized. Usually they put the anode on the left and the cathode on the right but not necessarily always.
- Sun Feb 23, 2020 8:20 pm
- Forum: Van't Hoff Equation
- Topic: Van't Hoff Equation
- Replies: 7
- Views: 550
Re: Van't Hoff Equation
The Van't Hoff Equation is used to find the new equilibrium constant of a solution at a different temperature, given the K at a different temperature.
- Sun Feb 23, 2020 8:18 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Standard vs Non
- Replies: 3
- Views: 263
Re: Standard vs Non
Standard cell potentials are the potentials of cells when they are under standard conditions (298K, 1ATM).
- Sun Feb 16, 2020 9:01 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Isochoric
- Replies: 8
- Views: 609
Re: Isochoric
An isochloric process is one that has constant volume.
- Sun Feb 16, 2020 9:00 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: reaction entropy
- Replies: 7
- Views: 602
Re: reaction entropy
Yes, this can be done because it is also a state function.
- Sun Feb 16, 2020 8:58 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Midterm Curve
- Replies: 45
- Views: 2277
Re: Midterm Curve
Lavelle does not curve his tests but sometimes in the past he has adjusted the final grades.
- Sun Feb 16, 2020 8:55 pm
- Forum: Phase Changes & Related Calculations
- Topic: change in entropy
- Replies: 7
- Views: 682
Re: change in entropy
Delta S is the measure of the entropy of a system, this means that a negative value would mean that the system becomes more orderly as a result of that process.
- Sun Feb 16, 2020 8:53 pm
- Forum: Van't Hoff Equation
- Topic: Hoff Equation
- Replies: 4
- Views: 199
Re: Hoff Equation
The Vant Hoff equation relates the equilibrium constant to the change in temperature when given the heat of formation for the process.
- Tue Feb 11, 2020 5:06 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: 4H.7 partc c
- Replies: 1
- Views: 138
4H.7 partc c
Can someone explain why the reaction SO2(g)+Br2(g)+2 H2O(l) --> H2SO4(aq) +2 HBr(aq) would cause a decrease in the entropy of the system?
- Sun Feb 09, 2020 8:54 pm
- Forum: Calculating Work of Expansion
- Topic: 4A.3
- Replies: 4
- Views: 193
Re: 4A.3
Because the problem describes an irreversible expansion with a constant external pressure, you use the equation w=-P(ex)(deltaV). The delta V is equal to the area of the region compressed or expanded times the distance compressed. Therefore the diameter given is used to find the area of the region c...
- Sun Feb 09, 2020 8:43 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: enthalpy
- Replies: 3
- Views: 250
Re: enthalpy
The sum of the work done on/by a system and the heat given off/absorbed by a system is equal to the enthalpy of a reaction. This being said, when there is a constant pressure, the delta H value is simply equal to the heat transfer.
- Sun Feb 09, 2020 8:39 pm
- Forum: Phase Changes & Related Calculations
- Topic: equipartition theorem
- Replies: 1
- Views: 119
Re: equipartition theorem
The equipartition theorem is the idea that the average value of each quadratic contribution to the energy of a molecule in a sample with temperature T is 1/2*k*T.
- Sun Feb 09, 2020 8:36 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE BOX
- Replies: 27
- Views: 887
Re: ICE BOX
if the k is smaller than 10^3, then the x in the ice box can be disregarded in the denominator.
- Sun Feb 09, 2020 8:34 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: reversible vs. irreversible
- Replies: 3
- Views: 171
Re: reversible vs. irreversible
A reversible process is one that can be reversed by an infinitely small change in a variable. For example, if the external pressure is equal to the pressure of the gas in the system, then even an infinitesimal decrease in external pressure will cause the piston to move out (work of expansion) and an...
- Sat Feb 01, 2020 7:55 pm
- Forum: Phase Changes & Related Calculations
- Topic: Reversible and Irreversible
- Replies: 5
- Views: 251
Re: Reversible and Irreversible
What is the relationship between whether a system is in equilibrium and whether or not the changes are reversible or irreversible?
- Sat Feb 01, 2020 7:52 pm
- Forum: Phase Changes & Related Calculations
- Topic: Open vs Isolated System
- Replies: 15
- Views: 1330
Re: Open vs Isolated System
In a closed system, energy can be exchanged with its surroundings while matter cannot. In an isolated system, neither mass nor energy can be exchanged with the surrounding universe.
- Sat Feb 01, 2020 7:48 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: isolated system
- Replies: 13
- Views: 636
Re: isolated system
An example of an isolated system is the combustion of glucose within a bomb calorimeter.
- Fri Jan 31, 2020 2:12 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: state property
- Replies: 8
- Views: 309
Re: state property
An example of something that is not a state function is heat (q) because it is energy in transit and does not depend on the initial and final values.
- Fri Jan 31, 2020 2:09 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Degeneracy
- Replies: 9
- Views: 364
Degeneracy
I understand that degeneracy is the number of ways that a given energy state is achieved but what exactly is degeneracy used for?
- Sun Jan 26, 2020 9:16 pm
- Forum: Phase Changes & Related Calculations
- Topic: enthalpy of phase changes
- Replies: 8
- Views: 263
Re: enthalpy of phase changes
No, calculating the enthalpy of a phase change will not be negative.
- Sun Jan 26, 2020 9:13 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase Changes
- Replies: 7
- Views: 245
Re: Phase Changes
The proper method is to calculate the enthalpy, then add the enthalpy of the phase change.
- Sun Jan 26, 2020 9:05 pm
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy is said to be additive
- Replies: 10
- Views: 333
Re: Enthalpy is said to be additive
being additive means that different enthalpies of different reactions can be added. this is true because enthalpy is a state function.
- Sun Jan 26, 2020 9:02 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Meaning of State Function
- Replies: 8
- Views: 237
Re: Meaning of State Function
state properties are those that are determined by its current state, independent on the path taken to obtain that state.
- Sun Jan 26, 2020 9:00 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Exothermic and Endothermic
- Replies: 11
- Views: 773
Re: Exothermic and Endothermic
Exothermic reactions have a negative delta H because the enthalpy of the products have less enthalpy than the reactants, and delta H is the difference between the products and the reactants, making the delta H negative. In endothermic reactions the products have a higher H than the reactants, making...
- Sun Jan 19, 2020 7:21 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: small Ka
- Replies: 5
- Views: 207
Re: small Ka
Yes, if the ka is smaller that 10^-3, but if the percentage ionization is greater than 5% then you should go back and do the entire quadratic equation.
- Sun Jan 19, 2020 7:18 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: pH and pOH
- Replies: 5
- Views: 246
Re: pH and pOH
Yes, pH+pOH =14, so this can be used to determine the other if you have either the pH or the pOH.
- Sun Jan 19, 2020 7:17 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Molar concentration of acids & bases
- Replies: 8
- Views: 406
Re: Molar concentration of acids & bases
It will ask specifically for pH or pOH if that's what they want. Otherwise, just give in the units of what they're asking for.
- Sun Jan 19, 2020 7:14 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ice boc
- Replies: 7
- Views: 258
Re: ice boc
The X can only be taken out if it is very small and would not make a significant impact on the overall calculation, but this is usually only in either the numerator or denominator, rarely both. Therefore not all of the Xs can be considered negligible.
- Sun Jan 19, 2020 7:12 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: When do we use the equilibrium sign?
- Replies: 7
- Views: 319
Re: When do we use the equilibrium sign?
The equilibrium sign is used in order to display that both the forward and reverse reactions are occurring. At equilibrium, this happens at the same rate, but the sign just symbolizes the presence of both reactions.
- Sun Jan 12, 2020 10:29 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Concentration
- Replies: 6
- Views: 248
Re: Concentration
We use units for concentration, but don't use it for the equilibrium constant.
- Sun Jan 12, 2020 10:24 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K Expression for Reverse Reaction
- Replies: 3
- Views: 164
Re: K Expression for Reverse Reaction
If you aren't using the K of the forward reaction, then yes you just switch the products and reactants in the expression.
- Sun Jan 12, 2020 10:17 pm
- Forum: Ideal Gases
- Topic: Ideal Gas Law
- Replies: 3
- Views: 126
Re: Ideal Gas Law
You can only use pV=nRT if there is low pressure and high temperature.
- Sun Jan 12, 2020 10:16 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Units for K
- Replies: 21
- Views: 671
Re: Units for K
In class, Dr. Lavelle mentioned briefly saying that technically K is the ratio if the activities of the products and reactants, which is unit-less.
- Sun Jan 12, 2020 10:05 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Q
- Replies: 10
- Views: 396
Re: Q
Yes, this is basically the only use.
- Sun Dec 08, 2019 11:04 pm
- Forum: Hybridization
- Topic: Pi bond
- Replies: 10
- Views: 787
Re: Pi bond
Yes, that is the definition of a pi bond.
- Sun Dec 08, 2019 11:02 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: -ate
- Replies: 11
- Views: 736
Re: -ate
You would use -ate if the the complex that you are naming is anionic.
Re: "Ferrate"
According to the textbook, if an element's name on the periodic table is based on their latin name, then that latin name is used in naming the coordination complex. This is also why copper is represented by "cuprate".
- Sun Dec 08, 2019 10:59 pm
- Forum: Biological Examples
- Topic: Cisplatin [ENDORSED]
- Replies: 19
- Views: 1336
Re: Cisplatin [ENDORSED]
Cisplatin is a helpful chemotherapy drug because it stops rapid cell division. However, it has recently stopped being used as frequently because of its inability to target malignant cells, meaning that rapidly dividing healthy cells (such as hair follicles) are also affected.
- Sun Dec 08, 2019 10:57 pm
- Forum: Amphoteric Compounds
- Topic: As2O3
- Replies: 3
- Views: 441
Re: As2O3
Amphoteric compounds have both basic and acidic properties. Since As2O3 exhibits properties of both it is indeed an amphoteric compound.
- Sun Dec 08, 2019 10:55 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: H2O ligand vs hydrate
- Replies: 2
- Views: 223
Re: H2O ligand vs hydrate
There is no difference in the naming of the H20 molecule.
- Sun Dec 01, 2019 11:47 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Breaking of pi and sigma bonds
- Replies: 4
- Views: 384
Re: Breaking of pi and sigma bonds
Sigma bonds have the ability to rotate, while pi bonds do not have this ability so the pi bonds will always break
- Sun Dec 01, 2019 11:45 pm
- Forum: Amphoteric Compounds
- Topic: amphoteric compounds
- Replies: 2
- Views: 197
Re: amphoteric compounds
An amphoteric compound is one that can act both as an acid and as a base.
- Sun Dec 01, 2019 11:40 pm
- Forum: Amphoteric Compounds
- Topic: amphiprotic and amphoteric
- Replies: 9
- Views: 748
Re: amphiprotic and amphoteric
An amphiprotic substance is a amphoteric substance that transfers H+ ions.
- Sun Dec 01, 2019 8:27 pm
- Forum: Bronsted Acids & Bases
- Topic: Lewis vs. Bronsted
- Replies: 3
- Views: 203
Lewis vs. Bronsted
What exactly is the difference between Lewis acids/bases and Bronsted acids/ bases?
- Sun Dec 01, 2019 8:19 pm
- Forum: Lewis Acids & Bases
- Topic: Proton acceptor and proton donor?
- Replies: 33
- Views: 2170
Re: Proton acceptor and proton donor?
Lewis acids donate protons, while Lewis bases accept them.
- Mon Nov 25, 2019 12:53 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent vs linear
- Replies: 56
- Views: 4294
Re: Bent vs linear
If a molecule has two lone pairs, whether or not it is bent or linear depends on the total number of regions of electron density.
- Mon Nov 25, 2019 12:49 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Number of Ligands
- Replies: 1
- Views: 113
Number of Ligands
Is there a way to tell how many ligands can attach to a transition metal if we don't know the oxidation state of the transition metal?
- Sun Nov 24, 2019 9:21 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Transition Metals
- Replies: 7
- Views: 464
Re: Transition Metals
I'm pretty sure all transition metals can form coordination compounds.
- Sun Nov 24, 2019 8:30 pm
- Forum: Hybridization
- Topic: Hybridization
- Replies: 1
- Views: 117
Re: Hybridization
Hybridization occurs in order to equalize the imbalance in the energy levels of electrons. The energy level of the hybridized orbitals lies in between the s and p (or d) orbitals.
- Sun Nov 24, 2019 8:20 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Formation of coordinate covalent bonds
- Replies: 2
- Views: 144
Re: Formation of coordinate covalent bonds
The number of ligands that attach must neutralize the charge of the transition metal, so the number that can attach depends on the charge of the central transition metal.
- Tue Nov 19, 2019 12:36 am
- Forum: Bond Lengths & Energies
- Topic: Hydrogen Bonding
- Replies: 13
- Views: 1117
Re: Hydrogen Bonding
In order for a hydrogen bond to form, it must be covalently bonded to Fluorine, Oxygen, or Nitrogen and it must be with a Fluorine, Oxygen, or Nitrogen atom with a lone pair. For example, the hydrogens in H2O interact with the Oxygen in water molecules (which has 2 lone pairs). Also, since Hydrogen ...
- Tue Nov 19, 2019 12:29 am
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Sigma and Pi Bonds
- Replies: 33
- Views: 1698
Re: Sigma and Pi Bonds
The order of which of the 3 bonds is sigma and which are pi isn't important, even the book doesn't spend very much time on that. I think we probably just have to know that a triple bond has 1 sigma bond and 2 pi bonds
- Tue Nov 19, 2019 12:19 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Pi Bond Rotation
- Replies: 2
- Views: 123
Re: Pi Bond Rotation
This means that the atoms with pi bonds (and the ones connected to atoms with pi bonds) are all in the same plane, since they cannot rotate like sigma bonds can.
- Tue Nov 19, 2019 12:17 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW 2E.13a VSEPR formula
- Replies: 1
- Views: 106
Re: HW 2E.13a VSEPR formula
The book uses A in all of its other VSEPR formulas other than in this question so I'd say it's safe to assume that the latter is also correct.
- Tue Nov 19, 2019 12:13 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E 19
- Replies: 1
- Views: 152
Re: 2E 19
You basically predict the shape around each central atom, so in the case of b, the shape is tetrahedral around the carbon atoms, and the bond angle around the beryllium is 180. You still use all the same rules as if this molecule had only one central atom.
- Sun Nov 10, 2019 11:25 pm
- Forum: Einstein Equation
- Topic: Wavelength and KE
- Replies: 5
- Views: 928
Re: Wavelength and KE
If you add the kinetic energy to the threshold energy, you get the energy per photon that's being used in this photoelectric experiment. From there you use E=hv and c=v(wavelength) to find the wavelength.
- Sun Nov 10, 2019 11:19 pm
- Forum: Photoelectric Effect
- Topic: Light acts as a wave
- Replies: 4
- Views: 421
Re: Light acts as a wave
The photoelectric effect is the one that supports the article properties of light, while de broglie supported the wave like properties. The photoelectric effect talks about how intensity doesn't affect the energy of light, where if there were solely wake like properties, this would not be the case.
- Sun Nov 10, 2019 11:00 pm
- Forum: Coordinate Covalent Bonds
- Topic: bond question
- Replies: 5
- Views: 408
Re: bond question
Yes, they do occur in nature. An example of one in nature is the Carbon-Nitrogen bond in amino acids.
- Sun Nov 10, 2019 10:55 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 Forces
- Replies: 3
- Views: 169
Re: London Forces
Yes, they occur in all atoms.
- Tue Nov 05, 2019 12:38 pm
- Forum: Octet Exceptions
- Topic: Radicals
- Replies: 2
- Views: 267
Radicals
How do you determine which element in a radical gets the lone electron? I'm looking at 2C.5 part a which is asking you to draw ClO. How do I know if the last electron does on Cl or O?
- Sun Nov 03, 2019 3:49 pm
- Forum: Resonance Structures
- Topic: moving an electron
- Replies: 4
- Views: 264
Re: moving an electron
A resonance structure is used to demonstrate that there are not fixed positions of electrons and that electrons do move around.
- Sun Nov 03, 2019 3:45 pm
- Forum: Ionic & Covalent Bonds
- Topic: Strength and Length
- Replies: 18
- Views: 935
Re: Strength and Length
The strength of a bond is measured by its dissociation energy. Longer bonds are easily broken and more likely to be involved in a reaction, while shorter bonds are harder to break and therefore less reactive. The longer the bond, the weaker it is.
- Sun Nov 03, 2019 3:26 pm
- Forum: Properties of Light
- Topic: De Broglie
- Replies: 3
- Views: 166
Re: De Broglie
An electron would have a faster speed (if they have the same wavelength) because it has a much smaller mass than a proton.
- Sun Nov 03, 2019 3:15 pm
- Forum: Lewis Structures
- Topic: Limiting Reactants
- Replies: 3
- Views: 139
Re: Limiting Reactants
When you convert the number of moles to grams, its usually the number of grams used in the reaction.
- Sun Nov 03, 2019 3:13 pm
- Forum: Einstein Equation
- Topic: eV
- Replies: 4
- Views: 342
Re: eV
the M stands for mega.
- Sun Oct 27, 2019 11:45 pm
- Forum: Electronegativity
- Topic: Fluorine's Electronegativity
- Replies: 6
- Views: 490
Re: Fluorine's Electronegativity
Fluorine is the most electronegative atom because it has 7 valence electrons (5 in the 2 p shell) and therefore is close to the optimal electron configuration, making it have a higher affinity for gaining another electron to reach the stable octet configuration.
- Sun Oct 27, 2019 11:43 pm
- Forum: Bond Lengths & Energies
- Topic: Double bond vs single bonds
- Replies: 4
- Views: 296
Re: Double bond vs single bonds
Double bonds are shorter than single bonds because the bonds are stronger an therefore they pull the atoms closer together.
- Sun Oct 27, 2019 10:50 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2A.23 question
- Replies: 8
- Views: 420
Re: 2A.23 question
In order to find the equation you have to look at the charges for magnesium ions and for arsenic ions. Magnesium ions have a charge of 2+ and arsenic ions have a charge of 3- so in order to balance the charges there must be three magnesium atoms and 2 arsenic atoms.
- Sun Oct 27, 2019 10:43 pm
- Forum: Electronegativity
- Topic: isoelectronic atoms
- Replies: 2
- Views: 157
Re: isoelectronic atoms
Yes, they should have the sane electronegativity because elements that are more electronegative have a higher change of gaining electrons and atoms that are isoelectronic have equal numbers of electrons.
- Sun Oct 27, 2019 10:39 pm
- Forum: Resonance Structures
- Topic: Resonance Structures
- Replies: 3
- Views: 144
Re: Resonance Structures
Resonance structures are necessary because the e- is not just occupying that one formation. The electrons are actually in a position that is an average of the possible structures so saying that one is correct is not true. We draw all of them because it shows that there is more than one possibility o...
- Sun Oct 20, 2019 9:35 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Stern & Gerlach Experiment
- Replies: 3
- Views: 233
Re: Stern & Gerlach Experiment
The experiment consisted of passing a beam of silver atoms through a magnetic field. When this was done, it split into two beams because the electrons that had an upward spin and those that had a downward spin created their own magnetic fields. The stern and Gerlach experiment determined the presenc...
- Sun Oct 20, 2019 9:23 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Kinetic Energy
- Replies: 4
- Views: 249
Re: Kinetic Energy
There is kinetic energy when the energy of the photons being aimed at the metal is greater than the work function. Therefore, if the energy of the photon is equal to the work function there is no kinetic energy. The kinetic energy is the excess energy from the photon therefore if there is no excess ...
- Sun Oct 20, 2019 9:18 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: p- & d- orbitals
- Replies: 2
- Views: 125
Re: p- & d- orbitals
The nodal plane of an orbital is where there is no probability that you will find an electron. This means that there are regions on the p- and d- orbitals where it is impossible to find an electron.
- Sat Oct 19, 2019 4:50 pm
- Forum: Photoelectric Effect
- Topic: Video module Test
- Replies: 3
- Views: 183
Re: Video module Test
If there is no kinetic energy, then the energy required to remove an electron from the metal is equal to the energy of the photon beam being directed at the metal. from there you use the equation E=hv to find the frequency, then c= (wavelength)(frequency) to find the greatest wavelength of light tha...
- Sat Oct 19, 2019 4:39 pm
- Forum: General Science Questions
- Topic: Midterm
- Replies: 17
- Views: 1005
Re: Midterm
You might be able to get a copy of previous years' midterm from the test bank at the Student Activities Center.
- Sun Oct 13, 2019 9:45 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Electron Configuration
- Replies: 5
- Views: 261
Re: Electron Configuration
Those coefficents before the "p" and "s" refer to the "n" number which usually corresponds to the period number except with the "d" block with is usually "n-1".
- Sun Oct 13, 2019 9:41 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic vs Covalent
- Replies: 32
- Views: 43763
Re: Ionic vs Covalent
Ionic bonds are stronger than covalent bonds
- Sun Oct 13, 2019 9:39 pm
- Forum: Properties of Light
- Topic: Photons
- Replies: 4
- Views: 259
Re: Photons
A photon is a light particle and its lack of mass can be explained by wave particle duality and the fact that the photon acts as both a particle and a wave.
- Sun Oct 13, 2019 9:35 pm
- Forum: SI Units, Unit Conversions
- Topic: Accuracy vs Precision
- Replies: 11
- Views: 791
Re: Accuracy vs Precision
Accuracy is how close your value is to the actual value while precision are multiple values close to each other regardless of the actual value.
- Sun Oct 13, 2019 9:31 pm
- Forum: Significant Figures
- Topic: How Many Sig Figs
- Replies: 7
- Views: 432
Re: How Many Sig Figs
For addition use the number of decimal places and for multiplication use the lowest number of sig figs
- Sun Oct 13, 2019 9:14 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg equation [ENDORSED]
- Replies: 73
- Views: 9125
Re: Rydberg equation [ENDORSED]
The Rydberg equation represents the frequency associated with an electron moving from one energy level to another. The frequency is equal to the Rydberg constant multiplied by the inverse of the final minus initial energy levels. You can use the equation when trying to find the frequency of the wave...
- Fri Oct 04, 2019 9:58 pm
- Forum: Empirical & Molecular Formulas
- Topic: What decimal place to round to when taking masses from the Periodic Table?
- Replies: 19
- Views: 2985
Re: What decimal place to round to when taking masses from the Periodic Table?
I think the most accurate way to go about taking masses from a periodic table is by taking the entire number that's given on the sheet and using in your calculations. This way you are sure to prevent rounding error and can then use the sig figs from the problem to round later on
- Fri Oct 04, 2019 9:56 pm
- Forum: Limiting Reactant Calculations
- Topic: Mass of AgCl produced?
- Replies: 2
- Views: 292
Re: Mass of AgCl produced?
Use the balanced equation to determine how many moles of product can be made with that many moles AgCl. Then multiply that number by the molar mass that you've given to determine how many grams of that product has been created