Search found 100 matches
- Sat Mar 14, 2020 3:03 pm
- Forum: Calculating Work of Expansion
- Topic: Increase/Decrease
- Replies: 6
- Views: 449
Re: Increase/Decrease
Expansion causes an increase in work because of the equation -PdeltaV in which more volume causes more work.
- Sat Mar 14, 2020 3:01 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Delta S
- Replies: 8
- Views: 683
Re: Delta S
Delta s total is the sum of delta s of surroundings and system.
- Sat Mar 14, 2020 2:57 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagram
- Replies: 11
- Views: 713
Re: Cell Diagram
Yes, you would place platinum electrodes in the sides with no solid electrodes, but other electrodes would be preferred depending on what's in the solution like iron electrodes are preferred if the solution contains iron and so on.
- Sat Mar 14, 2020 12:47 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Concentration Cell
- Replies: 3
- Views: 243
Re: Concentration Cell
Yes, anodes are the ones that are oxidized so they have lower concentrations while the cathodes are reduced so they have the greater concentration.
- Sat Mar 14, 2020 12:45 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Half/Rxn & Balanced Equations for galvanic cells.
- Replies: 8
- Views: 549
Re: Half/Rxn & Balanced Equations for galvanic cells.
Cells need solids electrodes in both sides to work, so if there is no solid electrode on any side, you place solid platinum to fulfill that necessity.
- Sun Mar 08, 2020 1:10 am
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: instantaneous rate
- Replies: 16
- Views: 925
Re: instantaneous rate
The instantaneous rate applies to a specific point in time which is more useful than an average rate as the graph may not be as consistently simple in which the average rate can be very different as to what the actual rate is.
- Sun Mar 08, 2020 1:04 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: the intermediate in a reaction
- Replies: 10
- Views: 680
Re: the intermediate in a reaction
Intermediates aren't included in the expression due to how it's produced in one step to be entirely consumed upon the next.
- Sun Mar 08, 2020 1:02 am
- 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: 1451
Re: Calculating ln Q
Q is the ratio of concentrations and/or partial pressures of products over reactants where the individual coefficients are to be used as exponents for each individual reactant/product. You can use Q to find other values of variables that are also on the Nernst equation if given enough additional inf...
- Sun Mar 08, 2020 12:57 am
- Forum: Second Order Reactions
- Topic: 7B.13
- Replies: 5
- Views: 456
Re: 7B.13
I believe they rounded at a certain point during the problem. I didn't round until the very end and got 756 seconds as well so you should be fine.
- Sun Mar 08, 2020 12:48 am
- Forum: Second Order Reactions
- Topic: 7B.3
- Replies: 5
- Views: 412
Re: 7B.3
You first find the concentration of A after B undergoes the change which is 0.153 M of A - (2 mol of A divided by 1 mol of B)*(0.034 mol of B per liter) which gives you 0.085 M of A afterwards. Then plug this concentration as well as the initial concentration into the rate law of the first order and...
- Sat Feb 29, 2020 9:29 pm
- Forum: Balancing Redox Reactions
- Topic: Reducing/Oxidizing Agents
- Replies: 13
- Views: 602
Re: Reducing/Oxidizing Agents
It tripped me up trying to comprehend this but I kind of think of them as opposites. So, the oxidizing agents are reduced and the reducing agents are oxidized.
- Sat Feb 29, 2020 9:26 pm
- Forum: Balancing Redox Reactions
- Topic: Cell Diagrams
- Replies: 14
- Views: 933
Re: Cell Diagrams
Yes, it's absolutely critical that the anodes are placed on the left side of the salt bridge and cathodes on the right side of the salt bridge.
- Sat Feb 29, 2020 9:25 pm
- Forum: Balancing Redox Reactions
- Topic: 6K3d Reduction Reaction
- Replies: 2
- Views: 218
Re: 6K3d Reduction Reaction
I thought it was a typo and others looked up the equation where the chemical equation appears to be Cl2 -> HClO + Cl- instead. So, the oxidation equation is 2H2O + Cl2 -> 2e- + 2HClO + 2H+ and the reduction equation is 2e- + Cl2 -> 2Cl-. Combine the equations, and you'll get H2O +Cl2 -> HClO + H+ + ...
- Sat Feb 29, 2020 9:12 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidizing/reducing agent
- Replies: 18
- Views: 1046
Re: Oxidizing/reducing agent
Oxidizing agents are what's being reduced thereby gaining electrons where vice versa, reducing agents are what's being oxidized thereby losing electrons.
- Sat Feb 29, 2020 9:01 pm
- Forum: Balancing Redox Reactions
- Topic: When to add H+ or H20
- Replies: 19
- Views: 2370
Re: When to add H+ or H20
For both acidic and basic solutions, you add H20 to balance the oxygens. Afterward for acidic solutions, you add H+ to balance the hydrogens; as for basic solutions, you add H20 to balance out the hydrogens but then add the same amount of OH- to the opposite side to maintain balance.
- Sun Feb 23, 2020 11:05 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Finding n
- Replies: 6
- Views: 406
Re: Finding n
For electrochemistry in this case, you can identify the n (as moles/electron in this case) from balancing your redox reaction since redox reactions involve the transfer of electrons.
- Sun Feb 23, 2020 11:01 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: salt bridge
- Replies: 5
- Views: 452
Re: salt bridge
Salt bridges are present in order to maintain charge balance because in the case of charge imbalance, the reaction would essentially stop.
- Sun Feb 23, 2020 10:58 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: porous disc
- Replies: 5
- Views: 398
Re: porous disc
Yes, they essentially have the same roles of keeping the cells neutral but the only difference is that with a porous disk, you don't place the anode and cathode in different beakers but rather together in the same solution.
- Sun Feb 23, 2020 10:54 am
- Forum: Balancing Redox Reactions
- Topic: oxidation numbers
- Replies: 5
- Views: 309
Re: oxidation numbers
What I usually do is identify the ones that are unchanging like how oxygen and ozone have oxidation numbers of zero. From, there I'd find the oxidation numbers for the transition metals or whatever other element/compounds there are. Based on the changes in oxidation numbers of some species in the re...
- Sun Feb 23, 2020 10:49 am
- Forum: Balancing Redox Reactions
- Topic: Oxidizing/Reducing Agents
- Replies: 11
- Views: 780
Re: Oxidizing/Reducing Agents
Oxidizing agents gain electrons and are reduced in a reaction whereas reducing agents lose electrons and are oxidized in a reaction.
- Sat Feb 15, 2020 5:32 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Intensive and Extensive Properties
- Replies: 8
- Views: 1833
Re: Intensive and Extensive Properties
Extensive properties are dependent upon the amount that you have like density whereas intensive properties aren't dependent on the amount present at all like specific heat capacity.
- Sat Feb 15, 2020 5:28 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Negative work
- Replies: 14
- Views: 889
Re: Negative work
Work is negative when a system is doing work because that's what it loses hence the negative. Conversely, it's positive if something else is doing work on the system.
- Sat Feb 15, 2020 5:25 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: P1/P2
- Replies: 10
- Views: 1159
Re: P1/P2
Pressure and volume are inversely proportional to each other therefore depending on what you're given, the ratio will always be V2/V1 or P1/P2.
- Sat Feb 15, 2020 5:22 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs and K value
- Replies: 3
- Views: 256
Re: Gibbs and K value
The effects can be seen in the equation deltaG = -RTlnK. If K is greater than 1, then delta G is negative indicating spontaneity whereas if K is less than 1, then delta G is positive indicating a nonspontaneous process.
- Sat Feb 15, 2020 5:15 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard Enthalpies of Formation
- Replies: 10
- Views: 516
Re: Standard Enthalpies of Formation
Elements in their most standard state (pure elements) possess an enthalpy of formation of 0 like graphite.
- Sun Feb 09, 2020 5:37 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Calculating K
- Replies: 15
- Views: 700
Re: Calculating K
The equation has to always be balanced to find both K and Q. The only difference is that K is for when it's at equilibrium whereas Q is not.
- Sun Feb 09, 2020 5:32 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: delta U
- Replies: 8
- Views: 205
Re: delta U
Adiabetic essentially means that no heat is entering or exiting, therefore it'd equate to 0 which would make deltaU equal to work.
- Sun Feb 09, 2020 5:28 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Weak acid/base
- Replies: 14
- Views: 624
Re: Weak acid/base
It's best to memorize them, but something like the pH scale and dissociability can indicate the strengths of acids/bases if given.
- Sun Feb 09, 2020 5:25 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Volume and Pressure
- Replies: 8
- Views: 246
Re: Volume and Pressure
Volume and pressure are inversely proportional so if volume increases, pressure must decrease and vice versa, but just remember that pressure can increase without changing volume by adding inert gases.
- Sun Feb 09, 2020 5:16 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law
- Replies: 10
- Views: 237
Re: Hess's Law
Enthalpy is a state function therefore the total enthalpy can be summed up which allows Hess's law to be used.
- Sat Feb 01, 2020 2:35 am
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy of sublimation?
- Replies: 8
- Views: 1377
Re: Enthalpy of sublimation?
We will eventually have to calculate the enthalpy of sublimation and is represented by the sum of the heat of fusion and the heat of vaporization.
- Sat Feb 01, 2020 2:30 am
- Forum: Phase Changes & Related Calculations
- Topic: internal energy
- Replies: 11
- Views: 561
Re: internal energy
Delta U is the internal energy. Q represents heat. Utilizing the two is through the equation: Delta U = q + w where w is the net work.
- Sat Feb 01, 2020 2:27 am
- Forum: Phase Changes & Related Calculations
- Topic: Phase Changes
- Replies: 17
- Views: 670
Re: Phase Changes
Looking on a heating curve, as the temperature reaches a certain point, it will remain constant before increasing again. That constant temperature is where the phase change occurs.
- Sat Feb 01, 2020 2:18 am
- Forum: Phase Changes & Related Calculations
- Topic: Calorimeter
- Replies: 8
- Views: 537
Re: Calorimeter
A calorimeter is just a "thermally insulated container" to measure changes of heat while a bomb calorimeter is the same thing but can withstand more pressure.
- Sat Feb 01, 2020 2:15 am
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy vs Change in Internal Energy
- Replies: 4
- Views: 280
Re: Enthalpy vs Change in Internal Energy
Enthalpy is just the heat absorbed or released during a reaction and you can just consider the internal energy as just the sum of all of the total energy contained in the system.
- Sat Jan 25, 2020 2:51 am
- Forum: Phase Changes & Related Calculations
- Topic: Celsius and Kelvin
- Replies: 11
- Views: 398
Re: Celsius and Kelvin
The two aren't numerically equal as there's a 273.15 difference between Celsius and Kelvin, but it'd probably be more useful if Kelvin were to be used as it's often compatible with many equations that involve temperature.
- Sat Jan 25, 2020 2:42 am
- Forum: Phase Changes & Related Calculations
- Topic: Endothermic values
- Replies: 5
- Views: 108
Re: Endothermic values
Adding the signs would be necessary otherwise people can't really tell if the reaction is endothermic or exothermic.
- Sat Jan 25, 2020 2:38 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 5.61f
- Replies: 5
- Views: 181
Re: 5.61f
Water is a solvent, indicating that it's a liquid which won't affect the equilibrium. Only aqueous and gaseous reactants or products can affect it.
- Sat Jan 25, 2020 2:34 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Partial Pressure
- Replies: 5
- Views: 218
Re: Partial Pressure
Increasing the partial pressure of something from one side causes the partial pressure of whatever else is on that same side to decrease and everything on the opposite side increases, and vice versa to maintain the proper ratio.
- Sat Jan 25, 2020 2:25 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Partial Pressure vs Pressure
- Replies: 7
- Views: 218
Re: Partial Pressure vs Pressure
You can think of partial pressure as relating to individual reactants or products while pressure applies to the entire system simultaneously.
- Sat Jan 18, 2020 2:46 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE Tables
- Replies: 3
- Views: 186
ICE Tables
Just as confirmation, you know to use ICE tables if you're given K and the initial concentrations/pressures correct? Is there anything else to identify in the problem to know if ICE charts should be used?
- Sat Jan 18, 2020 2:43 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Thermodynamic Stability
- Replies: 6
- Views: 314
Re: Thermodynamic Stability
You just look at the K value and compare them. Smaller K values indicate more thermodynamical stability and the opposite if the K value is bigger.
- Sat Jan 18, 2020 2:10 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5 percent rule
- Replies: 10
- Views: 490
Re: 5 percent rule
You use the 5 percent rule to make sure that the approximation that you made where x is 0 in the denominator when k is less than 10^-3 is valid and should be used every time you solve for equilibrium concentrations using the ICE chart.
- Sat Jan 18, 2020 2:01 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 6E.1
- Replies: 1
- Views: 173
Re: 6E.1
There are two equations that can be made for this problem because it's polyprotic. The first equation is H2SO4 + H2O = H3O + HSO4. But because it can still deprotonate, the second equation is HSO4 + H2O = H3O + SO4. You then make an ICE chart for this where the initial concentration of HSO4 and H3O ...
- Sat Jan 18, 2020 1:25 pm
- Forum: Ideal Gases
- Topic: Ideal Gas Law
- Replies: 5
- Views: 214
Re: Ideal Gas Law
The ideal gas law is typically used to convert between pressure and concentration. So, if you're given concentration and you're supposed to find Kp or vice versa, you know that you have to apply the equation.
- Thu Jan 09, 2020 3:07 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Effect of High Initial Concentration of Reactant
- Replies: 5
- Views: 218
Re: Effect of High Initial Concentration of Reactant
Yes, because the equilibrium constant will never change so you must maintain the product to reactant ratio. So if the reactant were to increase then the products would increase to maintain the proper ratio.
- Thu Jan 09, 2020 2:56 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K and Q
- Replies: 5
- Views: 197
Re: K and Q
Yes, because the equation used to find both are the exact same. The K value is when the reaction is at equilibrium so if Q equates to that then the reaction is definitely at equilibrium as well.
- Thu Jan 09, 2020 2:52 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: How to interpret reactions based on quotient in relation to equilibrium constant
- Replies: 5
- Views: 183
Re: How to interpret reactions based on quotient in relation to equilibrium constant
If Q<K, then the forward reaction is favored, resulting in more product to reach equilibrium while if Q>K, then the reverse reaction is favored which results in more reactants to reach equilibrium.
- Thu Jan 09, 2020 2:47 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: 5I.9
- Replies: 3
- Views: 194
Re: 5I.9
I'd assume that it'd be Kp because units of pressure is given, but I don't think it should be too concerning because you can convert between concentration and pressure anyways.
- Thu Jan 09, 2020 12:09 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Constant
- Replies: 2
- Views: 109
Re: Equilibrium Constant
The equilibrium constant is just the ratio of product to reactant. With the constant, you can determine the concentration or partial pressure for either one when given the constant and the reactant or product. Also, if either reactant or product changes to a certain amount, you can determine the amo...
- Sat Dec 07, 2019 2:39 pm
- Forum: Dipole Moments
- Topic: Dipole Moments Cancel in Tetrahedral?
- Replies: 5
- Views: 1007
Re: Dipole Moments Cancel in Tetrahedral?
If you draw out the proper shape, then obviously the molecule will be polar because of dipoles that aren't canceling each other out. So, it's only if the molecules are the same where the dipoles would cancel each other out.
- Sat Dec 07, 2019 2:32 pm
- Forum: Ionic & Covalent Bonds
- Topic: Nonpolar and polar
- Replies: 16
- Views: 1057
Re: Nonpolar and polar
You should see if the dipoles cancel out in the molecule. If they cancel, then it's nonpolar and if they don't then it's polar.
- Sat Dec 07, 2019 2:04 pm
- Forum: Hybridization
- Topic: Resonance
- Replies: 1
- Views: 106
Re: Resonance
You would typically only find the hybridization for the most stable resonance structure so I don't think you'd need to show the other resonance structures only the stable one.
- Sat Dec 07, 2019 2:01 pm
- Forum: Hybridization
- Topic: Question 2F.3
- Replies: 1
- Views: 129
Re: Question 2F.3
The more stable structure would be preferred. So, it's the one where S has two double bonds each connected to an O and a lone pair on top of S as well. Count the sigma and pi bonds for that structure.
- Sat Dec 07, 2019 1:58 pm
- Forum: Hybridization
- Topic: Lone pairs
- Replies: 4
- Views: 325
Re: Lone pairs
Yes, they do because they're also electron groups.
- Sat Nov 30, 2019 7:47 am
- Forum: Calculating the pH of Salt Solutions
- Topic: pH vs. pOH
- Replies: 17
- Views: 2262
Re: pH vs. pOH
pH measures acidity whereas pOH measures basicity. Both are primarily measured on a scale from 0-14 so if the pH is 4 then the pOH is 10 and so on.
- Sat Nov 30, 2019 7:42 am
- Forum: Lewis Acids & Bases
- Topic: HCl vs HF
- Replies: 19
- Views: 1312
Re: HCl vs HF
Cl is less electronegative than F which makes it easier to dissociate which makes HCl the stronger acid.
- Sat Nov 30, 2019 7:36 am
- Forum: Bronsted Acids & Bases
- Topic: Bronsted Acid and base
- Replies: 8
- Views: 463
Re: Bronsted Acid and base
A Lewis acid accepts an e- pair while a Lewis base donates an e- pair. Bronsted acids donate protons while bronsted bases accepts protons.
- Sat Nov 30, 2019 7:31 am
- Forum: Hybridization
- Topic: Resonance Structures and hybridization
- Replies: 1
- Views: 94
Re: Resonance Structures and hybridization
I think you're supposed to use the hybridization of the most stable resonance structure which you can find through formal charge.
- Sat Nov 30, 2019 7:28 am
- Forum: Lewis Acids & Bases
- Topic: Proton acceptor and proton donor?
- Replies: 33
- Views: 2024
Re: Proton acceptor and proton donor?
Bronsted Acids donate protons and Bronsted Bases accepts protons.
- Thu Nov 21, 2019 10:47 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: When to Use Formal Charge
- Replies: 4
- Views: 421
Re: When to Use Formal Charge
Formal charge tells you which resonance structure is more stable so with it you'll be able to find the preferred form of a molecule
- Thu Nov 21, 2019 10:45 pm
- Forum: Bond Lengths & Energies
- Topic: Boiling Point
- Replies: 7
- Views: 1888
Re: Boiling Point
Both SiH4 and SiF4 are nonpolar which mean that they only display LDF forces. So when both molecules have LDF you look at the size. The F is more bigger than H so SiF4 is the bigger one of the two which makes it have stronger LDF forces so higher boiling point.
- Thu Nov 21, 2019 10:28 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Sigma and Pi Bonds
- Replies: 33
- Views: 1538
Re: Sigma and Pi Bonds
You don't need to order the bonds. Just know how many sigma and pi bonds are present in each kind of bond (Triple Bond = 1 Sigma Bond and 2 Pi Bonds,etc.)
- Thu Nov 21, 2019 10:04 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: Hydrogen Bonding Rules
- Replies: 6
- Views: 366
Re: Hydrogen Bonding Rules
Each lone pair is a potential hydrogen bonding site, so in your case a nitrogen atom with TWO lone pairs would have TWO potential hydrogen bonding sites.
- Thu Nov 21, 2019 9:52 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: 3F 15
- Replies: 5
- Views: 909
Re: 3F 15
You would consider the weight if both molecules are not polar which is not the case here. AsF3 displays dipole-dipole interactions which indicates it's polar while AsF5 only displays LDF forces so it's not polar. Dipole-dipole is stronger than any LDF so AsF3 would have the higher boiling point.
- Sat Nov 16, 2019 5:13 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR and Polarity
- Replies: 4
- Views: 115
VSEPR and Polarity
Just for confirmation, what do you generally look at in a VSEPR model to determine polarity of a molecule?
- Sat Nov 16, 2019 5:12 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: polar vs nonpolar
- Replies: 6
- Views: 294
Re: polar vs nonpolar
Generally, you can't really determine polarity just off of the molecular formula which is why you use the VSEPR models to determine it as it is the actual accurate representation of the molecule.
- Sat Nov 16, 2019 5:01 pm
- Forum: Sigma & Pi Bonds
- Topic: sigma bonds
- Replies: 3
- Views: 291
Re: sigma bonds
Depending on which two atoms that have bonds together, they may have a single bond (1 sigma bond), a double bond (1 sigma and 1 pi bond), or a triple bond (1 sigma and 2 pi bonds).
- Sat Nov 16, 2019 4:59 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Symmetry and Polarity
- Replies: 13
- Views: 921
Re: Symmetry and Polarity
Symmetry shouldn't really be what you're looking for to determine polarity but rather use the VSEPR models instead because VSEPR models are the actual representation and Lewis structures are just inaccurate base models.
- Sat Nov 16, 2019 4:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent or Angular
- Replies: 13
- Views: 1060
Re: Bent or Angular
Bent and angular are the same thing, but I'd probably use angular just because it's how the book calls it.
- Sat Nov 09, 2019 9:08 pm
- Forum: Dipole Moments
- Topic: Dipole-dipole, LDF, HB
- Replies: 1
- Views: 225
Re: Dipole-dipole, LDF, HB
Dipole-dipole is when the positive end of a molecule and the negative end of another molecule attract, LDF is when electrons create temporary dipoles, and hydrogen bonds is when a hydrogen atom bonds with a highly electronegative atom (N,F,O). In terms of energy needed to break these interactions, L...
- Sat Nov 09, 2019 8:22 pm
- Forum: Dipole Moments
- Topic: Induced Dipole-Induced Dipole Interactions
- Replies: 1
- Views: 80
Re: Induced Dipole-Induced Dipole Interactions
It's when a molecule with a dipole comes in contact with an atom with no dipole. The electrons in the atom then react to the molecule to create a dipole in the atom itself.
- Sat Nov 09, 2019 8:08 pm
- Forum: Dipole Moments
- Topic: Electronegativity on Dipoles
- Replies: 3
- Views: 154
Re: Electronegativity on Dipoles
The bigger the electronegativity difference, the greater the dipole moment will be. And yes, if there if is any difference in the electronegativity, then you should consider that there is a dipole moment.
- Sat Nov 09, 2019 7:46 pm
- Forum: Electronegativity
- Topic: Differences
- Replies: 3
- Views: 251
Re: Differences
Ionization is the process of forming ions by losing or gaining electrons, electron affinity is like how likely the atom is to gain an electron, and electronegativity is how likely the atom would take an electron.
- Sat Nov 09, 2019 7:40 pm
- Forum: Ionic & Covalent Bonds
- Topic: Bond Strength
- Replies: 12
- Views: 1032
Re: Bond Strength
Aside from looking at the electronegativity aspect, I think of it as how covalent bonds pretty much involve the sharing of electrons whereas ionic bonds involve the attractions of opposite charged ions which makes it much more harder to break.
- Sat Nov 02, 2019 2:18 am
- Forum: Ionic & Covalent Bonds
- Topic: Anions and Cations
- Replies: 9
- Views: 432
Re: Anions and Cations
Anions gain electrons whereas cations lose electrons so basically anions get heavier and cations get lighter.
- Sat Nov 02, 2019 2:14 am
- Forum: Lewis Structures
- Topic: central atom
- Replies: 16
- Views: 2128
Re: central atom
The electron with the least electronegativity is the one that is the central atom but pretty much most of the time it's the element with the least amount of atoms in the molecule.
- Sat Nov 02, 2019 2:11 am
- Forum: Lewis Structures
- Topic: Electrons Moving Around
- Replies: 3
- Views: 181
Re: Electrons Moving Around
Electrons don't really leave, but rather they are shared among atoms to form ions.
- Sat Nov 02, 2019 2:04 am
- Forum: Sigma & Pi Bonds
- Topic: Significance of sigma and pi bonds
- Replies: 4
- Views: 275
Re: Significance of sigma and pi bonds
Pretty much single bonds contain one sigma bond, double bonds contain a sigma and a pi bond, and triple bonds have one sigma and two pi bonds.
- Sat Nov 02, 2019 1:52 am
- Forum: DeBroglie Equation
- Topic: When to use the de Broglie equation?
- Replies: 5
- Views: 271
Re: When to use the de Broglie equation?
Yeah, you pretty much use the De Broglie equation when you're given or given enough to find either the mass, velocity, or wavelength of an object that is not massless.
- Sat Nov 02, 2019 1:45 am
- Forum: Trends in The Periodic Table
- Topic: Noble Gases
- Replies: 10
- Views: 614
Re: Noble Gases
Noble gases have full valence shells which make them not needing to take or give any electrons which exclude them from the trends.
- Sat Nov 02, 2019 1:41 am
- Forum: Properties of Electrons
- Topic: Mass of an Electron
- Replies: 14
- Views: 483
Re: Mass of an Electron
Electrons in any element or whatever else they're present in all have the same size which is 9.10938356 × 10^-31 kilograms.
- Sat Nov 02, 2019 1:39 am
- Forum: Properties of Electrons
- Topic: Formal Charge of an Atom
- Replies: 5
- Views: 294
Re: Formal Charge of an Atom
Formal charge is calculated by utilizing the formula: Valence Electrons - (# of Lone Electron Pairs + # of Bonding Electrons/2).
- Sat Nov 02, 2019 1:33 am
- Forum: Properties of Electrons
- Topic: Electron removal
- Replies: 11
- Views: 383
Re: Electron removal
The further the electrons are from the nucleus, the less the force of attraction is from the protons to the electrons, hence the further electrons are easier to remove.
- Sat Nov 02, 2019 1:30 am
- Forum: Properties of Light
- Topic: Speed of light
- Replies: 13
- Views: 344
Re: Speed of light
Electromagnetic radiation move at the same speed as the speed of light hence we use the constant 2.998 x 10^8 m/s for both subjects.
- Sat Oct 19, 2019 2:53 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Spectral Series
- Replies: 3
- Views: 213
Re: Spectral Series
Each series has their own range of wavelengths. Once you've found the wavelength the photon's at, then you can just link them to whichever series involves that range.
- Sat Oct 19, 2019 2:50 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Paired Electrons
- Replies: 5
- Views: 158
Re: Paired Electrons
To add on to that, each orbital is placed one electron at a time. When all of the orbitals have been placed and there are still more electrons, then each one will be paired up with each electron that was already placed in the orbitals.
- Sat Oct 19, 2019 2:45 pm
- Forum: DeBroglie Equation
- Topic: De Broglie's Equation
- Replies: 17
- Views: 550
Re: De Broglie's Equation
Photons don't have mass so the equation isn't applicable for it.
- Sat Oct 19, 2019 2:42 pm
- Forum: Properties of Electrons
- Topic: Wave Function
- Replies: 5
- Views: 222
Re: Wave Function
Wave functions just tell us what the shape of the orbitals so you can basically tell where the electron's going to be.
- Sat Oct 19, 2019 2:37 pm
- Forum: Properties of Light
- Topic: Quantum equations
- Replies: 5
- Views: 191
Re: Quantum equations
Honestly, any unit of distance in the metric system per a unit of time is fine because they can all be converted anyway, but normally people write it as m/s or maybe unless otherwise stated.
- Sat Oct 12, 2019 4:42 pm
- Forum: Properties of Light
- Topic: Amplitude
- Replies: 12
- Views: 519
Re: Amplitude
Amplitude just indicates how high or low the waves themselves travel. But in terms of its relationship to frequency and wavelength, it probably doesn't matter as amplitude isn't present in the equations that we've been using so far.
- Sat Oct 12, 2019 4:34 pm
- Forum: *Black Body Radiation
- Topic: Black Body Radiation
- Replies: 12
- Views: 692
Re: Black Body Radiation
More specifically, it's thermal electromagnetic radiation.
- Sat Oct 12, 2019 4:31 pm
- Forum: Properties of Light
- Topic: Speed of Light
- Replies: 41
- Views: 2699
Re: Speed of Light
The speed of light won't because it's a constant but sometimes they might be displayed differently due to sig figs and rounding and whatnot.
- Sat Oct 12, 2019 4:29 pm
- Forum: Properties of Electrons
- Topic: Electron After Excited State
- Replies: 7
- Views: 393
Re: Electron After Excited State
When the electron reaches an excited state, it jumps to a higher energy level where they release photons to go back to the original state.
- Sat Oct 12, 2019 4:17 pm
- Forum: Einstein Equation
- Topic: Planck's Constant
- Replies: 3
- Views: 290
Re: Planck's Constant
The relationship is displayed in E(energy)=h(Planck's constant)v(frequency). Planck's constant is the constant of proportionality which shows the direct relationship between energy and frequency. The higher the frequency, the higher the energy output, and vice versa. The Planck's constant doesn't re...
- Fri Oct 04, 2019 9:06 pm
- Forum: Limiting Reactant Calculations
- Topic: Percent or theoretical yield
- Replies: 14
- Views: 1251
Re: Percent or theoretical yield
Percent yield is basically the ratio of actual yield to theoretical yield, and theoretical yield is the maximum amount of product that you can possibly get based off of your limiting reactant.
- Fri Oct 04, 2019 9:01 pm
- Forum: Significant Figures
- Topic: Sig Figs
- Replies: 3
- Views: 108
Re: Sig Figs
Usually when you're adding or subtracting you tend to round your answer to the least number of places to the decimal point in the problem. Ex: 1.234+1.2 gives you 2.434 but you round it to 2.4. And as for multiplying or dividing you literally just use the smallest number of sig figs out of the value...
- Thu Oct 03, 2019 7:03 pm
- Forum: SI Units, Unit Conversions
- Topic: Formula Names
- Replies: 7
- Views: 397
Re: Formula Names
Most of the problems you'll do will require you to write out chemical equations so yeah, you'll pretty much have to remember polyatomic ions especially in case the question won't give you the chemical formula for the compounds that you'll need.
- Thu Oct 03, 2019 6:43 pm
- Forum: Balancing Chemical Reactions
- Topic: Fractions in Balancing Equations
- Replies: 11
- Views: 13020
Re: Fractions in Balancing Equations
Typically, if you can't use a whole number as a stoichiometric coefficient for whatever it is you're balancing is when you use a fraction. It's so you can just multiply every coefficient in the equation with the denominator of the fraction to get all the coefficients as whole numbers without messing...
- Thu Oct 03, 2019 6:40 pm
- Forum: SI Units, Unit Conversions
- Topic: Chemistry Community Question
- Replies: 3
- Views: 121
Re: Chemistry Community Question
I thought they were due this Friday, but apparently it's due this Sunday.