Search found 101 matches
- Sun Mar 14, 2021 11:15 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridges
- Replies: 41
- Views: 2787
Re: Salt Bridges
they are necessary to prevent buildup !
- Sun Mar 14, 2021 11:13 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: when to add Pt (s)
- Replies: 23
- Views: 882
Re: when to add Pt (s)
it's added when on any side of the cell there is no conducting metal
- Sun Mar 14, 2021 11:12 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Bond Enthalpies
- Replies: 8
- Views: 393
Re: Bond Enthalpies
yes they should be given to you through a chart!
- Sun Mar 14, 2021 11:11 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: specific vs molar heat capacity
- Replies: 16
- Views: 769
Re: specific vs molar heat capacity
molar heat capacity is the amount of energy needed to raise the temp of a mole of substance by 1 degree. specific heat capacity is the amount of energy needed to raise the temp of a gram of a substance by a degree
- Sun Mar 14, 2021 11:09 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Catalyst
- Replies: 27
- Views: 997
Re: Catalyst
it lowers the activation energy so that the reaction can occur faster!
- Sun Mar 07, 2021 11:13 pm
- Forum: Ideal Gases
- Topic: Exo vs Endothermic
- Replies: 40
- Views: 2172
Re: Exo vs Endothermic
think about physically what is happening in the equation. exothermic means it releases energy while endothermic means it absorbs!
- Sun Mar 07, 2021 11:11 pm
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy vs heat
- Replies: 31
- Views: 2073
Re: Enthalpy vs heat
enthalpy is the change in heat within a system. heat is the transfer of energy between systems.
- Sun Mar 07, 2021 11:10 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidizing Agent
- Replies: 33
- Views: 1165
Re: Oxidizing Agent
high reduction potential means its good at oxidizing.
- Sun Mar 07, 2021 11:09 pm
- Forum: First Order Reactions
- Topic: Equation Confusion
- Replies: 16
- Views: 609
Re: Equation Confusion
Zero order reactions are associated with he first and first order reactions are associated with the second!
- Sun Mar 07, 2021 11:08 pm
- Forum: Balancing Redox Reactions
- Topic: How to Determine if a Reaction is in Basic or Acidic Solution?
- Replies: 53
- Views: 2762
Re: How to Determine if a Reaction is in Basic or Acidic Solution?
the question usually gives you that info!!!
- Sun Feb 28, 2021 11:27 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Tips for what gas constant to use
- Replies: 10
- Views: 563
Re: Tips for what gas constant to use
look at the units given and find the equations that fit that!
- Sun Feb 28, 2021 11:25 pm
- Forum: *Organic Reaction Mechanisms in General
- Topic: K meaning
- Replies: 29
- Views: 2016
Re: K meaning
K is the Boltzmann constant which is on the equation sheet
- Sun Feb 28, 2021 11:23 pm
- Forum: *Electrophiles
- Topic: Is F a electrophile or nucleophile?
- Replies: 16
- Views: 2735
Re: Is F a electrophile or nucleophile?
F is an electrophile because it needs an electron. meanwhile, F- is a nucleophile because it has lone pairs to donate.
- Sun Feb 28, 2021 11:22 pm
- Forum: *Electrophiles
- Topic: Nucleophile vs Electrophile
- Replies: 7
- Views: 2767
Re: Nucleophile vs Electrophile
nucleophiles can donate lone pairs while electrophiles want to gain an electron
- Sun Feb 28, 2021 11:20 pm
- Forum: *Electrophiles
- Topic: Anode vs Cathode
- Replies: 16
- Views: 1342
Re: Anode vs Cathode
An Ox and a Red Cat helped me in high school!!
- Sun Feb 21, 2021 10:50 pm
- Forum: Balancing Redox Reactions
- Topic: cool acronym
- Replies: 25
- Views: 1369
Re: cool acronym
this one helped me all throughout high school as well! thank you for sharing!
- Sun Feb 21, 2021 10:50 pm
- Forum: Balancing Redox Reactions
- Topic: coefficients for oxidation number
- Replies: 22
- Views: 4652
Re: coefficients for oxidation number
no they dont need to be part of the calculation
- Sun Feb 21, 2021 10:49 pm
- Forum: Balancing Redox Reactions
- Topic: Redox Mnemonic
- Replies: 11
- Views: 942
Re: Redox Mnemonic
OIL RIG is one that has helped me through all of high school!
- Sun Feb 21, 2021 10:48 pm
- Forum: Balancing Redox Reactions
- Topic: salt bridge
- Replies: 19
- Views: 614
Re: salt bridge
The salt bridge connects both sides so as to allow the ions move from each side to the other.
- Sun Feb 21, 2021 10:47 pm
- Forum: Balancing Redox Reactions
- Topic: Reducing vs oxidizing agents
- Replies: 16
- Views: 745
Re: Reducing vs oxidizing agents
I like to just think of the complete opposite. oxidizing agents are being reduced so they gain e-. therefore, reducing agents lose e-.
- Sun Feb 14, 2021 11:47 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy definition
- Replies: 37
- Views: 2057
Re: Entropy definition
it measures disorder in a system!
- Sun Feb 14, 2021 11:46 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy: kJ or J?
- Replies: 30
- Views: 1412
Re: Entropy: kJ or J?
you have to convert into J/K!!
- Sun Feb 14, 2021 11:45 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Adding Equations
- Replies: 16
- Views: 732
Re: Adding Equations
yes they do bc they are all state functions
- Sun Feb 14, 2021 11:45 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Sapling question 4
- Replies: 9
- Views: 391
Re: Sapling question 4
∆S = nRln(V2/V1) is the equation I used. You are given multiple parts of this equation already so you can just solve it for ∆S
- Sun Feb 14, 2021 11:42 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: confusion with notation
- Replies: 11
- Views: 465
Re: confusion with notation
d is for derivatives!
- Sun Feb 07, 2021 11:52 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Work on a system
- Replies: 27
- Views: 1011
Re: Work on a system
Thank you for all of these! they really helped in helping me understand the different ways work can be applied to a system.
- Sun Feb 07, 2021 11:51 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Systems
- Replies: 24
- Views: 745
Re: Systems
I believe in his lecture, Dr. Lavelle described the universe as an isolated system as there is nothing outside of it and no matter or energy is able to be exchanged.
- Sun Feb 07, 2021 11:49 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Entropy
- Replies: 27
- Views: 1000
Re: Entropy
I really appreciated this new perspective of what entropy is as what I assumed it to be was randomness as discussed in lecture!
- Sun Feb 07, 2021 11:48 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: closed system
- Replies: 43
- Views: 1407
Re: closed system
A closed system does not allow for an exchange of matter. Think of “closed doors” as nothing comes in!
- Sun Feb 07, 2021 11:46 pm
- Forum: Calculating Work of Expansion
- Topic: The Sign of Work
- Replies: 7
- Views: 296
Re: The Sign of Work
A way that helps me remember that work done by the system is negative is that the system loses energy just as in any subtractive property, and vice versa, work done onto the system is positive as it gains energy in an additive property
- Sun Jan 31, 2021 11:51 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Effect of Pressure (contraction) in reaction
- Replies: 8
- Views: 249
Re: Effect of Pressure (contraction) in reaction
during compression, reactions favors the side with the least amount of moles, so in this example it would shift to the left.
- Sun Jan 31, 2021 11:49 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Endothermic and Exothermic Concepts
- Replies: 12
- Views: 523
Re: Endothermic and Exothermic Concepts
endothermic reactions need heat added to break the bonds, but that means it'll favor the products because breaking the bonds makes products.
- Sun Jan 31, 2021 11:47 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Clarification on pKw
- Replies: 15
- Views: 3500
Re: Clarification on pKw
pKw will always be 14 because it is a constant!
- Sun Jan 31, 2021 11:45 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Sapling #4
- Replies: 7
- Views: 425
Re: Sapling #4
if the reactants require more energy to break the bonds compared to the products, then it is endothermic. exothermic reaction have stronger bonds in the products.
- Sun Jan 31, 2021 11:41 pm
- Forum: Phase Changes & Related Calculations
- Topic: Higher Enthalpy
- Replies: 6
- Views: 181
Re: Higher Enthalpy
high to low enthalpy means that it is exergonic and releases energy, which means that it would favor reactants.
- Sun Jan 24, 2021 11:39 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: isolated system
- Replies: 16
- Views: 744
Re: isolated system
yes because isolated systems cant exchange energy or matter!
- Sun Jan 24, 2021 11:34 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: intensive vs extensive
- Replies: 12
- Views: 760
Re: intensive vs extensive
extensive depends on the amount of a substance (ex: mass) while intensive doesn't depend on the amount of a substance (ex: density).
it is important to know so that you can use the right constants in your equation
it is important to know so that you can use the right constants in your equation
- Sun Jan 24, 2021 11:31 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Differences
- Replies: 6
- Views: 557
Re: Differences
isolated systems can't exchange energy or matter so no outside sources can affect the reaction, open systems can exchange both energy and matter so a lot of outside factors can affect the reaction, and closed systems can only exchange energy so few outside sources such as temperature can affect the ...
- Sun Jan 24, 2021 11:28 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Open Systems
- Replies: 15
- Views: 784
Re: Open Systems
since open systems allow for the exchange of matter and energy, I think that any thermodynamic equation can be used so long as you pay attention to if it has constant pressure and volume
- Sun Jan 24, 2021 11:26 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: closed system
- Replies: 43
- Views: 1407
Re: closed system
Closed systems have a fixed amount of matter and don't allow for the exchange of matter. A clear example would be like the water bottle example mentioned above. A closed water bottle doesn't allow the water inside to leak!
- Sun Jan 17, 2021 11:42 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Units to know
- Replies: 11
- Views: 473
Re: Units to know
I think for pressure, you need to know atm and torr!
- Sun Jan 17, 2021 11:38 pm
- Forum: Ideal Gases
- Topic: Kc vs. Kp
- Replies: 71
- Views: 2191
Re: Kc vs. Kp
Kc and Kp are calculated in the same way and both can be used for gases, but the only difference is that one is for partial pressures and one is for concentration. for whichever version you choose, make sure youre consistent with it the whole way through!
- Sun Jan 17, 2021 11:36 pm
- Forum: Ideal Gases
- Topic: Gas for equilibrium equation
- Replies: 8
- Views: 395
Re: Gas for equilibrium equation
P is used to note that it is partial pressure being used instead of concentration! but both Kc and Kp can be used for gases
- Sun Jan 17, 2021 11:34 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 1 #5
- Replies: 8
- Views: 527
Re: Sapling Week 1 #5
yes just multiply them!!
- Sun Jan 17, 2021 11:33 pm
- Forum: Ideal Gases
- Topic: Inverse Kc [ENDORSED]
- Replies: 41
- Views: 1841
Re: Inverse Kc [ENDORSED]
if it goes fro A+B--> C then it would be K but if it goes from C-->A+B then it would be 1/K
- Sun Jan 17, 2021 11:29 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Box
- Replies: 10
- Views: 479
Re: ICE Box
if it gives you the initial value, then the change is -(stoich coefficient)x but if there is no initial concentration, then the change is +(stoich coefficient)x
- Sun Jan 10, 2021 10:22 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: change in K
- Replies: 22
- Views: 760
Re: change in K
because K is a constant, the only thing that changes K is temperature :)
- Sun Jan 10, 2021 10:20 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling #2
- Replies: 3
- Views: 199
Re: Sapling #2
definitely use the ICE table as the other responses said, but also don't forget to divide the moles by liters in order to get molarity!
- Sun Jan 10, 2021 10:19 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G.1
- Replies: 4
- Views: 194
Re: 5G.1
yes Q would change!!
- Sun Jan 10, 2021 10:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Concentration vs Pressure
- Replies: 9
- Views: 507
Re: Concentration vs Pressure
when calculating, yes they are the same mathematically, but conceptually they are different. concentration is solely based on moles whereas partial pressures are related to temperatures and moles
- Sun Jan 10, 2021 10:14 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Stoichiometric Coefficients
- Replies: 5
- Views: 92
Re: Stoichiometric Coefficients
I don't think Lavelle explained it either, but as long as you remember that they become exponents when calculating K and Q, then I think you should be fine :)
- Tue Dec 15, 2020 8:10 pm
- Forum: Hybridization
- Topic: Double Pi Bonds
- Replies: 6
- Views: 836
Re: Double Pi Bonds
So in a triple bond, one is a sigma bond and 2 are pi bonds. For the sigma bonds, they will overlap end to end, but for the pi bonds, they have to overlap side by side. The 2 pi bonds are formed when the unoccupied p orbitals that are not overlapping end to end then overlap side by side with the oth...
- Tue Dec 15, 2020 8:04 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation #s help
- Replies: 5
- Views: 319
Oxidation #s help
How oxidation numbers, I know that you would usually look at the number of ligands attached to the central Atom and based off their charges calculate the oxidation number of the whole molecule, but if there is an atom attached to the outside (so not the central atom), can you use only that atom to c...
- Tue Dec 15, 2020 8:02 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis acids and bases vs Bronsted Acids and Bases
- Replies: 4
- Views: 305
Lewis acids and bases vs Bronsted Acids and Bases
What exactly is the difference between these two? or can I assume that a Lewis acid is a bronsted base and a Lewis base is a bronsted acid.
- Tue Dec 15, 2020 7:59 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Bond Angles
- Replies: 12
- Views: 524
Bond Angles
For a lewis structure with 3 bonds and one lone pair have a bond angle closer to 106 (from lecture) or will it have a bond angle that is just less than that of a tetrahedral (109.5)?
- Tue Dec 15, 2020 7:57 pm
- Forum: Bronsted Acids & Bases
- Topic: Acids in solution
- Replies: 5
- Views: 279
Acids in solution
Hello,
In lecture Lavelle stated that acid in a solution will be at pH 6. Does he mean the acid itself is at pH 6 or does he mean the solution will become pH 6?
In lecture Lavelle stated that acid in a solution will be at pH 6. Does he mean the acid itself is at pH 6 or does he mean the solution will become pH 6?
- Sun Dec 06, 2020 11:28 pm
- Forum: Dipole Moments
- Topic: London Dispersion Forces
- Replies: 10
- Views: 788
Re: London Dispersion Forces
London dispersion forces happen in all molecules because electrons are constantly moving around the nucleus and when electrons randomly become closer to each other, they create temporary dipoles which is a form of attraction.
- Sun Dec 06, 2020 11:26 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: sigma vs pi bonds
- Replies: 33
- Views: 1912
Re: sigma vs pi bonds
Sigma bonds are in all bonds while pi bonds are only in double and triple bonds. In a single bond there is only one sigma bond. In a double bond, there is one sigma and one pi bond and in a triple bond there is one sigma and 2 pi bonds.
- Sun Dec 06, 2020 11:23 pm
- Forum: Biological Examples
- Topic: Hemoglobin
- Replies: 13
- Views: 703
Re: Hemoglobin
Hemoglobins transports oxygen through the blood and myoglobins store oxygen in the muscles
- Sun Dec 06, 2020 11:21 pm
- Forum: Lewis Acids & Bases
- Topic: Water
- Replies: 63
- Views: 2581
Re: Water
it can act as both!
- Sun Dec 06, 2020 11:20 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Concept of pH
- Replies: 10
- Views: 530
Re: Concept of pH
high H+ count is acidic and low H+ count is basic
- Fri Nov 27, 2020 12:54 pm
- Forum: Hybridization
- Topic: Sapling #12
- Replies: 29
- Views: 961
Re: Sapling #12
The hybridization of atoms depends on the number of regions of electron density. both C and O have 4 regions, therefore it has a sp3 hybridization.
- Fri Nov 27, 2020 12:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sapling 17
- Replies: 8
- Views: 503
Re: Sapling 17
I made 2 linear structures as well with the first containing double bonds between all 3 carbons and the carbons at the ends each have 2 hydrogens attached with a single bond. The next linear structure had the 3 carbons connected by a single and a triple bond. The single bonded carbon at the end has ...
- Fri Nov 27, 2020 12:43 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sapling 16
- Replies: 6
- Views: 306
Re: Sapling 16
having a delocalized pi bond means that the pi bond doesn't have one set place and had the option to be placed elsewhere within the molecule. You know that there are delocalized pi bonds usually when there are resonance structures.
- Fri Nov 27, 2020 12:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: sigma bonds and single bonds
- Replies: 5
- Views: 254
Re: sigma bonds and single bonds
sigma bonds occur in single, double, and triple bonds. I like to think of it kinda like how London forces are present in all bonds. The only additional info you need to know is that double and triple bonds also contain pi bonds, with double bonds having one pi bond and triple bonds having two.
- Fri Nov 27, 2020 12:37 pm
- Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
- Topic: ionic liquids
- Replies: 8
- Views: 887
Re: ionic liquids
it is a salt in a liquid state and has a really low melting point
- Fri Nov 27, 2020 12:35 pm
- Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
- Topic: Liquid crystals
- Replies: 2
- Views: 532
Re: Liquid crystals
A liquid crystal has properties between those of typical liquids and solids. They are able to flow like a liquid but will be arranged in a way similar to crystals.
- Mon Nov 23, 2020 12:01 am
- Forum: Coordinate Covalent Bonds
- Topic: How?
- Replies: 3
- Views: 217
How?
How do I know if it will actually bond to make a coordinate covalent bond? I understand that one accepts the pair and one donates the pair, but how do you know if it will willingly donate?
- Mon Nov 23, 2020 12:00 am
- Forum: Octet Exceptions
- Topic: Expanded octets
- Replies: 2
- Views: 241
Expanded octets
How do I know how big expanded octets can expand?
- Sun Nov 22, 2020 11:59 pm
- Forum: Bond Lengths & Energies
- Topic: Higher Melting Point
- Replies: 28
- Views: 2437
Re: Higher Melting Point
CHI3 has a higher melting point because it has stronger bonds. Because of its size, it has more polarizability.
- Sun Nov 22, 2020 11:58 pm
- Forum: Dipole Moments
- Topic: Dipole Moments [ENDORSED]
- Replies: 3
- Views: 199
Dipole Moments [ENDORSED]
Can someone please explain what a dipole moment is? I know that dipoles have partial charges but what is a dipole moment?
- Sun Nov 22, 2020 11:57 pm
- Forum: Resonance Structures
- Topic: Resonance Structures
- Replies: 4
- Views: 288
Resonance Structures
How do I know the true length of bonds when there are resonance structures? Specifically, how do I know which ones contribute the most?
- Sun Nov 15, 2020 7:56 am
- Forum: Bond Lengths & Energies
- Topic: Covalent Bond Length
- Replies: 13
- Views: 1307
Re: Covalent Bond Length
the higher the electronegativity of the atom, the stronger the pull on electrons meaning that the bond length would be shorter and stronger. same goes for atomic radius. if the atoms have a small radius, the electrons are more tightly held, meaning the bonds would be stronger and shorter. triple bon...
- Sun Nov 15, 2020 7:51 am
- Forum: Lewis Structures
- Topic: how to draw lewis structures w double bonds
- Replies: 3
- Views: 254
how to draw lewis structures w double bonds
how do you know if you need to make the central atom have a double bond with the other atoms or if you can just leave them as lone pair electrons on the central atom?
- Sun Nov 15, 2020 7:49 am
- Forum: Resonance Structures
- Topic: Determining oxidation numbers?
- Replies: 9
- Views: 307
Re: Determining oxidation numbers?
the oxidation numbers of all the atoms should equal the charge on the whole compound. on the sapling question, we know that oxygen has an oxidation number of -2, so if there are four oxygens (-2x4=-8) and the whole compound needs to equal -1, then the oxidation number of chlorine should be +7
- Sun Nov 15, 2020 7:40 am
- Forum: Lewis Structures
- Topic: Lewis structure based on oxidation #
- Replies: 2
- Views: 108
Re: Lewis structure based on oxidation #
on the hint given by sapling, it states that the sum of the oxidation numbers is equal to the formal charge of the molecule. knowing that there was a formal charge of -1 on the whole molecule and that the four oxygens each had a oxidation number of -2 (totaling to -8), you can deduce the chlorine at...
- Sun Nov 15, 2020 7:38 am
- Forum: Electronegativity
- Topic: hydrogen bonds w/ carbon
- Replies: 5
- Views: 778
hydrogen bonds w/ carbon
why can't H make a hydrogen bond with carbon? I understand that hydrogen bonds can be made with N, O, and F because they're extremely electronegative and so they pull electrons towards them (making it partially negative), but then the difference in electronegativity of carbon and hydrogen is not sig...
- Sun Nov 08, 2020 11:59 pm
- Forum: Lewis Structures
- Topic: Lewis Structure Drawing
- Replies: 2
- Views: 76
Lewis Structure Drawing
Hi what is the general guideline for drawing lewis structures? Thanks!
- Sun Nov 08, 2020 11:58 pm
- Forum: Octet Exceptions
- Topic: octet rule exceptions
- Replies: 6
- Views: 175
Re: octet rule exceptions
1. odd number of electrons in molecules, ex: NO
2. when 1+ atoms in a molecule have 8+ electrons, ex: SF6
3. when 1+ atoms in a molecule have >8 electrons, ex: BCl3
2. when 1+ atoms in a molecule have 8+ electrons, ex: SF6
3. when 1+ atoms in a molecule have >8 electrons, ex: BCl3
- Sun Nov 08, 2020 11:55 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy/Effective Nuclear Charge
- Replies: 3
- Views: 155
Re: Ionization Energy/Effective Nuclear Charge
I think they're relieved because the oxygen atom needs one electron in the p levels to be stable and when its ionized, the electrons are spinning in opposing ways.
- Sun Nov 08, 2020 11:52 pm
- Forum: Ionic & Covalent Bonds
- Topic: HW Question
- Replies: 2
- Views: 112
Re: HW Question
Start by drawing the lewis structure of the compound and you'll notice that hydrogen bonds can occur for NOF atoms because they'll bond to the lone pairs. This means that there will be 8.
- Sun Nov 01, 2020 5:35 am
- Forum: Properties of Light
- Topic: 1A.3 Question
- Replies: 3
- Views: 129
Re: 1A.3 Question
The answer is C because using the equation c=wavelength*v we know that c is a constant. Therefore if there are bigger wavelengths, then the frequency must decrease and if there are smaller wavelengths, then frequency must increase (they are inversely related). The change in the electrical field refe...
- Sun Nov 01, 2020 5:23 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Sapling HW Q17
- Replies: 18
- Views: 1210
Re: Sapling HW Q17
An easy way to remember atomic radius size trends on the periodic table is that it increases going to the left and it increases going down. The explanation above does a good job of explaining why, but this is just a little too for memorization purposes :)
- Sun Nov 01, 2020 5:17 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Sapling HW Q21
- Replies: 4
- Views: 247
Re: Sapling HW Q21
The trend for electron affinity on the periodic table is that it increases from left to right and it decreases from top to bottom. Those with high electron affinity are also more likely to release energy when placing an electron while those with low electron affinity will absorb energy. Therefore, B...
- Sun Nov 01, 2020 5:11 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Affinity
- Replies: 4
- Views: 240
Re: Electron Affinity
When an electron has a high electron affinity, it will release a lot of energy when it gains an electron while one w a low electron affinity will release very little energy and absorb it.
- Sun Nov 01, 2020 5:00 am
- Forum: Trends in The Periodic Table
- Topic: Question about Ionization energy
- Replies: 4
- Views: 151
Re: Question about Ionization energy
Hello, Ionization energy is the energy needed to remove an electron, so I guess it could just describe the concept as a whole, whereas the first ionization energy is the energy needed to remove an electron from a neutral atom while the second ionization is the energy needed to remove an electron fro...
- Sun Oct 25, 2020 11:42 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Energy Level Excited
- Replies: 8
- Views: 361
Re: Energy Level Excited
An excited electron is one that gains energy through photons and this makes it move to an energy level higher than the ground state. I like to think of the ground state as the base level that electrons are already on. So when it moves from a higher energy level back to its ground state, it is releas...
- Sun Oct 25, 2020 11:38 pm
- Forum: Properties of Electrons
- Topic: Geiger and Marsden Experiment
- Replies: 2
- Views: 98
Re: Geiger and Marsden Experiment
They were able to discover that atoms had a concentrated mass within the nucleus (including all the positive charges) through their foil experiment because of how the the alpha particle beamed scattered after hitting foil. They found that most of the particles could go through and only a tiny fracti...
- Sun Oct 25, 2020 11:18 pm
- Forum: Ionic & Covalent Bonds
- Topic: Strength of bonds
- Replies: 13
- Views: 548
Re: Strength of bonds
Covalent bonds are the strongest bonds, hydrogen bonds are the weakest, and ionic bonds are moderately strong. I hope this helps :)
- Sun Oct 25, 2020 11:04 pm
- Forum: Photoelectric Effect
- Topic: Photons vs electrons
- Replies: 2
- Views: 108
Re: Photons vs electrons
I agree with the statement above. In the photoelectric effect, we want the energy in the photon to be enough to eject one electron. Therefore, they would have to be a 1:1 ratio. Hopefully, this is helpful!
- Sun Oct 25, 2020 11:00 pm
- Forum: Properties of Light
- Topic: 1A.9 problem
- Replies: 7
- Views: 377
Re: 1A.9 problem
To convert 300 MHz to Hz you would multiply it by 10^6. This is because Hz refers to the frequency, in which one cycle goes every second. MHz or Megahertz indicates millions, which is 1 x 10^6. I hope this helps!
- Sun Oct 18, 2020 11:36 pm
- Forum: Limiting Reactant Calculations
- Topic: General Limiting Question
- Replies: 9
- Views: 775
Re: General Limiting Question
For the most part, the limiting reactant determines how much products can be produced with the full consumption of that reactant, so technically yes. Making less products than calculated possible with the limiting reactant is also a possibility. I hope this helps!
- Sun Oct 18, 2020 11:32 pm
- Forum: Balancing Chemical Reactions
- Topic: Syntax Question
- Replies: 4
- Views: 381
Re: Syntax Question
Yes they are the same! It is essentially like math where if you have something in parentheses and they are multiplied by a number, that number gets distributed to everything inside the parentheses. In this case, (OH) has a subscript of 2, there for it would be distributed to the O and the H to make ...
- Sun Oct 18, 2020 11:25 pm
- Forum: Significant Figures
- Topic: How do I know how many sig figs to use?
- Replies: 6
- Views: 8868
Re: How do I know how many sig figs to use?
When you multiply or divide, your answer should have the same number of sig figs as the value with the smallest number of significant figures. 55.5 (3 sig figs) / 2.5 (2 sig figs) = 22.2, but you need only 2 sig figs so it would be 22. When you add or subtract, you answer should have the same number...
- Sun Oct 18, 2020 8:13 pm
- Forum: Balancing Chemical Reactions
- Topic: Textbook Problem H.11
- Replies: 1
- Views: 600
Re: Textbook Problem H.11
For the second stage, I believe those are the right compounds, but you just have to balance them. So from what we know about Fe3O4 + CO -------> Fe + CO2, we can see that there is more Fe on the left than the right. To balance this, we simply add a 3 in front of the Fe on the right to create Fe3O4 +...
- Sun Oct 18, 2020 7:58 pm
- Forum: Significant Figures
- Topic: How to use Scientific Notation
- Replies: 9
- Views: 458
Re: How to use Scientific Notation
They multiply and divide normally. For mw personally, it may be a little more work but I take the terms out of their scientific notation and multiply/divide normally, then put my answer back into scientific notation with the correct number of sig figs. This helps me make sure that I am doing it corr...
- Sun Oct 11, 2020 5:13 am
- Forum: Molarity, Solutions, Dilutions
- Topic: Formulas involved in Determining Solution Concentration
- Replies: 8
- Views: 697
Re: Formulas involved in Determining Solution Concentration
I was also confused about this when doing the sapling homework, as I tried to use m1v1-m2v2 when in reality all I had to do was use m=n/v. I think from that problem I learned that you just have to look closely at what they give you. if the question gives you any 3 parts of the m1v1=m2v2 formula, tha...
- Sun Oct 11, 2020 5:02 am
- Forum: Significant Figures
- Topic: Scientific Notation
- Replies: 4
- Views: 126
Scientific Notation
Should we always be using scientific notation for our answers? I know this question can be a little vague so if anyone has any overall tips for when to use scientific notation/how to use scientific notation I would really appreciate it!
- Sun Oct 11, 2020 4:58 am
- Forum: Significant Figures
- Topic: When should I start looking at sig figs?
- Replies: 31
- Views: 1321
Re: When should I start looking at sig figs?
I think for more accuracy, you should keep all the decimals during intermediate steps and then use sig figs for your final result. For example, if you get an answer during step one and then round it and then use that rounded number for step two and so on, the likelihood of error increases between ea...
- Sun Oct 11, 2020 4:49 am
- Forum: Significant Figures
- Topic: Sig Fig for numbers like 200, 3300, 4000
- Replies: 6
- Views: 293
Re: Sig Fig for numbers like 200, 3300, 4000
To begin, there are 4 rules for sig figs. 1. any digit that isn't a 0 is significant 2. any zeros sandwiched between 2 non-zero digits are significant 3. leading zeros aren't significant 4. if there is a decimal point, any zeros trailing a non-zero digit is significant Therefore, 0.005 actually has ...