Search found 102 matches
- Sat Mar 13, 2021 8:09 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: when can we not use -0.0592/n when finding the E of a cell?
- Replies: 10
- Views: 717
Re: when can we not use -0.0592/n when finding the E of a cell?
What would the standard conditions be? Would it just be 1 mol at 298 K?
- Sat Mar 13, 2021 7:49 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Value of N
- Replies: 24
- Views: 1032
Re: Value of N
N represents the number of moles of electrons that are being transferred in the reaction. You can only find N once you have balanced out the equation.
- Sat Mar 13, 2021 7:41 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Sapling HW Week 9/10 #17
- Replies: 9
- Views: 471
Re: Sapling HW Week 9/10 #17
To find the activation energy of the reverse reaction, you add the activation energy and the positive delta H (this is when the bonds are being broken down).
- Sat Mar 13, 2021 7:25 pm
- Forum: Experimental Details
- Topic: Psuedo First Order
- Replies: 7
- Views: 1408
Re: Psuedo First Order
Is the rate always going to depend on the reactant with smallest concentration? A pseudo rate is considered when there are too many changing concentrations. For instance, it is difficult to calculate the rate when you have k[A][B], and both A and B are changing. As such, you make one significantly ...
- Sat Mar 13, 2021 6:51 pm
- Forum: Zero Order Reactions
- Topic: Equation with dt
- Replies: 6
- Views: 437
Re: Equation with dt
I think the dt at the end of the equation is used for derivatives/calculus. I don't think it'll come up on the final.
- Sun Mar 07, 2021 2:04 pm
- Forum: General Rate Laws
- Topic: Sapling 9/10 #5
- Replies: 10
- Views: 2734
Re: Sapling 9/10 #5
I first thought of the plugging in 1 to both [A] and [B]. Once plugging 1 in and solving for the rate, it would come out as just 1. Then, I plugged in the new numbers: 1/2 to [A] and 3 to [B]. The rate comes out as 9/2. 9/2 is the factor of which the rate would change when the [A] was halved and [B]...
- Sun Mar 07, 2021 1:41 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: average rate
- Replies: 11
- Views: 575
Re: average rate
When you solve for the average rate, the answer may appear as a negative number. However, it should always be positive we are looking at the forward reaction. Dr. Lavelle mentioned it lecture about it.
- Sun Mar 07, 2021 1:36 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Catalyst
- Replies: 9
- Views: 540
Re: Catalyst
How do we know that an element/compound is created/made? I know that catalysts aren't formed or used up but appear on both sides of a process of reactions. Also, if they appear on both sides, would they appear on the final rate law?
- Sun Mar 07, 2021 1:26 pm
- Forum: Second Order Reactions
- Topic: second order relation to second order integrated law
- Replies: 5
- Views: 442
Re: second order relation to second order integrated law
The second order reaction is derived from the second order integrated rate law, which is 1/[A]=kt+1/[A]0. This equation involves the concentrations as well as the rate constant of the second-order reaction.
- Sun Mar 07, 2021 2:39 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Sapling Week 9/10 #13
- Replies: 2
- Views: 183
Re: Sapling Week 9/10 #13
I was wondering how you would find the substitute of [HClO]? Like how would you know what to put on the reactants and the products side?
- Sun Feb 28, 2021 2:01 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Sapling week 7/8 #11
- Replies: 6
- Views: 337
Re: Sapling week 7/8 #11
To find whether the reaction is spontaneous or not, you use the equation ∆G˚=-nFE˚. If E˚> 0, then ∆G˚ would be negative, making the reaction spontaneous. If Eº < 0, then ∆G˚ would be positive, making the reaction not spontaneous.
- Sun Feb 28, 2021 1:54 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Gibbs free energy
- Replies: 18
- Views: 993
Re: Gibbs free energy
Standard Gibbs free energy is a fixed value for a reaction under standard conditions. Gibbs free energy is the energy that is available to do work and transfer in and out of the system.
- Sun Feb 28, 2021 1:43 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Sapling Week 7/8 #12
- Replies: 5
- Views: 234
Re: Sapling Week 7/8 #12
I think your E˚cell value is might be wrong. I got E˚cell = 1.758V, but everything else looks correct! So it shoud be, G˚ = -(6 mol)(F Cmol-1)(1.758 V) / 1000 J.
- Sun Feb 28, 2021 1:20 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Sapling Week 7/8 #15
- Replies: 3
- Views: 233
Re: Sapling Week 7/8 #15
To find the cell potential, you need to use the Nernst equation. Eo − [(RT)/(nF)]ln(Q). You find Eo by subtracting the standard cell potential of the cathode by that of the anode. The n is the number of electrons transferred, and F is Faraday's constant. Q can be found by using the given concentrati...
- Sun Feb 28, 2021 1:05 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling 7/8 #17
- Replies: 8
- Views: 451
Re: Sapling 7/8 #17
For this problem, you use the Nernst Equation. However, instead of lnQ, you use logQ. Eo would be 0V because we are under S.H.E. Q in this question would equal PH2/[H+]^2.
- Sun Feb 21, 2021 11:45 pm
- Forum: Balancing Redox Reactions
- Topic: Oxygen
- Replies: 12
- Views: 596
Re: Oxygen
Oxygen will have an oxidation number of 0 when it is in its natural state (so when it's O2 or O3) When oxygen is in a compound, (i.e. KClO2) it will have an oxidation number of -2.
- Sun Feb 21, 2021 11:41 pm
- Forum: Balancing Redox Reactions
- Topic: Salt Bridge Diagram
- Replies: 8
- Views: 408
Re: Salt Bridge Diagram
To draw/write out a salt diagram, I think it's best to place the anode on the left and the cathode on the right. However, it kinda depends on on the diagram and equation. The electron flow goes from the anode to the cathode.
- Sun Feb 21, 2021 11:36 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidizing vs Reducing
- Replies: 55
- Views: 2092
Re: Oxidizing vs Reducing
Oxidizing is when a substance is losing electrons. Reducing is when a substance is gaining an electron.
- Sun Feb 21, 2021 11:33 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling Week 7/8 #1
- Replies: 10
- Views: 1980
Re: Sapling Week 7/8 #1
KClO2⟶KCl+O2 As an uncombined element, O2 has a oxidation number of 0. KClO2 and KCl are both ionic compounds. K in both compounds will have a charge of +1. That means Cl will be -1 in the KCl compound. However, this is not the case for KClO2. Since oxygen will have a charge of -2 when it is in a co...
- Sun Feb 21, 2021 10:52 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling week 7/8 #2
- Replies: 5
- Views: 1152
Re: Sapling week 7/8 #2
For this problem, you first want to look at the charge of the element on both sides of the equation. The charges on both sides should be equal. So in the In⟶In3+ equation, there are 3 more electrons on the left side than the right. So, to balance it, we add 3 electrons on the right: ln⟶ ln3+ + 3e-. ...
- Sun Feb 14, 2021 8:34 pm
- Forum: Environment, Fossil Fuels, Alternative Fuels
- Topic: Fuel cells
- Replies: 12
- Views: 2098
Re: Fuel cells
A fuel cell is thermodynamically feasible when ΔG is negative, which would mean it would be spontaneous.
- Sun Feb 14, 2021 8:24 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: higer molar entropy
- Replies: 13
- Views: 563
Re: higer molar entropy
The entropy is higher when the atm is lower because at lower pressures, the volume is greater (volume and pressure are inversely proportional). With a greater volume, there is more states the particles can achieve. Therefore, there is a greater entropy (S). If the atm was higher, then the entropy wo...
- Sun Feb 14, 2021 8:07 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: internal energy ideal gas
- Replies: 5
- Views: 278
Re: internal energy ideal gas
∆U = 0 for an isothermal expansion of an ideal gas because the work that is done within the system is replaced by energy in the form of heat. This means that Q = -W, which also can be written as ∆U = Q + W, which also equals 0.
- Sun Feb 14, 2021 7:54 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: ΔH
- Replies: 14
- Views: 566
ΔH
In lecture #14, Lavelle went over the relationship between ΔS with T(temp). What did he mean when he said that "the ΔH(rxn) plays an important role at low temperatures"? Can someone clarify how it relates back to the relationship between ΔS and T?
- Sun Feb 14, 2021 2:59 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: delta G
- Replies: 9
- Views: 474
Re: delta G
Delta G represents the change in free energy of the reaction. Delta G Knot represents the change in free energy of the reaction when it is under standard conditions.
- Sun Feb 07, 2021 1:03 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Identification
- Replies: 8
- Views: 486
Re: Identification
Elements that are in its pure form are the most stable. So diatomic elements and other specific compounds (like graphite) are pure.
- Sun Feb 07, 2021 12:38 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: constant pressure in open beaker
- Replies: 8
- Views: 349
Re: constant pressure in open beaker
The pressure in an open system is going to be constant because it has little to no effect on the external pressure, which is the pressure of the atmosphere.
- Fri Feb 05, 2021 3:00 am
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: enthalpy constants?
- Replies: 6
- Views: 532
Re: enthalpy constants?
I think that those constants are used for ideal gases.
- Fri Feb 05, 2021 2:41 am
- Forum: Calculating Work of Expansion
- Topic: Work notation
- Replies: 10
- Views: 382
Re: Work notation
Work is represented by "w". "W" represents degeneracy.
- Fri Feb 05, 2021 2:37 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: delta U conceptual question
- Replies: 7
- Views: 292
Re: delta U conceptual question
Yes, I believe that delta U can equal 0. Delta U is zero when there is no change in internal energy, which would occur when the system is isolated.
- Sun Jan 31, 2021 10:52 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: When to convert mass of a substance given to moles
- Replies: 5
- Views: 223
Re: When to convert mass of a substance given to moles
Question 10 of the sapling deals with delta H of fusion, which deals with moles.
- Sun Jan 31, 2021 10:43 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Enthalpy vs. Entropy
- Replies: 18
- Views: 562
Re: Enthalpy vs. Entropy
Enthalpy is the heat energy required to form and break bonds in a chemical reaction. It is represented as H. Entropy is the amount of disorder in a system. It is represented as S.
- Sun Jan 31, 2021 9:09 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy
- Replies: 5
- Views: 260
Re: Enthalpy
Enthalpy energy is the heat energy that is related to the forming and breaking of bonds in a chemical reaction. Internal energy is the total energy (kinetic and potential energy) in the system.
- Sun Jan 31, 2021 8:58 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Diatomic molecules standard enthalpy of formation
- Replies: 22
- Views: 1156
Re: Diatomic molecules standard enthalpy of formation
The standard enthalpy of formation be 0 only when the compound is in its most stable state. The diatomic molecules that are in the standard state are H2, N2, F2, O2, I2, Cl2, Br2. I believe it also depends on the phase they are in.
- Sun Jan 31, 2021 2:06 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam
- Replies: 33
- Views: 1693
Re: Steam
Thank you everyone for responding! I understand it now! :)
- Sun Jan 24, 2021 1:17 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: standard states
- Replies: 6
- Views: 306
Re: standard states
The ones I can remember he saying in class were graphite, O2, and H2. Were there any others he explicitly mention?
- Sun Jan 24, 2021 1:15 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Best Method for Finding Enthalpy Changes
- Replies: 6
- Views: 257
Re: Best Method for Finding Enthalpy Changes
I believe he said that method 3 was the "best", but method 1 was also an accurate way to calculate enthalpy change. It really depends on what you're given in a problem.
- Sun Jan 24, 2021 1:12 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat released/ gained
- Replies: 22
- Views: 890
Re: Heat released/ gained
When bonds are broken, energy is gained. This is related to the boiling/melting point of a compound. When bonds are formed, energy is released. This is related to freezing/condensing.
- Sun Jan 24, 2021 1:04 pm
- Forum: Phase Changes & Related Calculations
- Topic: Steam
- Replies: 33
- Views: 1693
Steam
I'm still a bit confused on why steam causes more severe burns compared to water at 100°C. Is it because the energy that released when it touches someone's hand is still going to be the same temperature when it is a gas, compared to when it is a water, which would temperature would decrease as more ...
- Sun Jan 24, 2021 12:51 pm
- Forum: Phase Changes & Related Calculations
- Topic: Define Phase Change
- Replies: 78
- Views: 4745
Re: Define Phase Change
Phase change is when a phase (solid, gas, and liquid) either melting, boiling, or freezing. The process of a phase changing to another phase is a phase change. For example, ice that melts to water is a phase change: it is melting.
- Fri Jan 15, 2021 8:58 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Constant
- Replies: 2
- Views: 161
Re: Equilibrium Constant
I'm not entirely sure if there is a high pressure that there will be an higher equilibrium constant. All that is important is that the equilibrium constant stays the same if we change the pressure or the volume. Only a change in temperature will change the k value.
- Fri Jan 15, 2021 8:53 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Textbook Problem 5I #15
- Replies: 4
- Views: 395
Re: Textbook Problem 5I #15
Since the problem gives the moles of NH3 in the beginning of the reaction, you would write 0.2 mol/L for the initial concentration for NH3. Then, you would solve for x just how you would for any other ICE box.
- Fri Jan 15, 2021 8:51 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling #3
- Replies: 5
- Views: 276
Re: Sapling #3
When your squaring your products, make sure you are squaring both the variable and the coefficient. (2x)^2 should equal 4x^2. Next, you should multiply out the denominator. Then, you should solve for x using the quadratic formula.
- Fri Jan 15, 2021 8:48 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Strong Acid and Base
- Replies: 4
- Views: 226
Re: Strong Acid and Base
H+ or OH- would have molar concentrations because when strong acids/bases react with water, they completely dissociate. H+ can also be written as H3O+. Since H+ and OH- are products in the reaction, they must have a concentration. Dissociation does not mean they disappear.
- Fri Jan 15, 2021 8:41 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: K in endo and exo when temp. decreases
- Replies: 11
- Views: 478
Re: K in endo and exo when temp. decreases
When decreasing the temp, the k value will increase. This is an exothermic reaction. You can also see if the reaction is exothermic if delta H is negative.
- Thu Jan 07, 2021 10:31 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE tables
- Replies: 11
- Views: 462
Re: ICE tables
Just to ask, if we are given a value for the products in the question as well has initial values for the reactants, would we include them in the I part of the ICE table?
- Thu Jan 07, 2021 10:18 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5.i #11
- Replies: 4
- Views: 154
Re: 5.i #11
You have to change mmol to mol/L. First change to mmol to mol and then divide by volume (L) to get the molarity.
- Thu Jan 07, 2021 10:16 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: HW problem
- Replies: 4
- Views: 178
Re: HW problem
For this question, you would need to add two or more equations together. Adding equations together is the same as adding numbers except the substances on their sides, stay on their respective sides (so like on the left or on the right). Next, in order to get the equation to exactly match with all th...
- Thu Jan 07, 2021 10:03 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: dobule arrows
- Replies: 6
- Views: 200
Re: dobule arrows
"<<" refers to how much smaller (or larger depending on what you're looking at) the number/variable is compared to the other number/variable.
- Thu Jan 07, 2021 10:01 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc
- Replies: 11
- Views: 285
Re: Kc
For Kc, you would use the molar concentration of the substances in the system. If the question asked you to find the Kp, you would use partial pressures of the substances in the system.
- Tue Dec 15, 2020 2:40 pm
- Forum: Air Pollution & Acid Rain
- Topic: acid rain
- Replies: 5
- Views: 428
Re: acid rain
For acid rain, you should know that it is formed in the atmosphere when carbon dioxide reacts with water, which produces carbonic acid and becomes acid rain.
H2O + CO2 --> H2CO3
H2O + CO2 --> H2CO3
- Tue Dec 15, 2020 2:25 pm
- Forum: Conjugate Acids & Bases
- Topic: Fundamental J.13 Part C
- Replies: 4
- Views: 242
Re: Fundamental J.13 Part C
For bronsted acid and bases and lewis acids and bases, it's pretty clear on what is a conjugate acid/base. However, I'm not entirely sure if neutralized reactions have a conjugate acid and base. I don't think they do because the products are water and a salt.
- Tue Dec 15, 2020 2:12 pm
- Forum: Amphoteric Compounds
- Topic: Recognizing Amphoteric Compounds
- Replies: 9
- Views: 632
Re: Recognizing Amphoteric Compounds
^^ yeah an amphoteric compound is a compound that can be an acid or base in a reaction. The most basic example is water, H2O. Since it can both accept or donate an H+, it can be bronsted acid or base.
- Tue Dec 15, 2020 2:09 pm
- Forum: Polyprotic Acids & Bases
- Topic: Polyprotic Acids and Bases
- Replies: 4
- Views: 265
Re: Polyprotic Acids and Bases
Yeah so polyprotic acid and bases accept/donate more than 1 proton, in other words H+.
- Tue Dec 15, 2020 2:05 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: Solving PH/PoH
- Replies: 11
- Views: 1024
Re: Solving PH/PoH
Yeah just know the relationship between pH, pOH, [H+], [OH-]. If you know the relationships among them well, you should be good!
- Sun Dec 06, 2020 10:34 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Types of Salts
- Replies: 7
- Views: 564
Re: Types of Salts
There are no such things as a strong or weak salt because salts do not affect the pH.
- Sun Dec 06, 2020 10:21 pm
- Forum: Conjugate Acids & Bases
- Topic: NH3
- Replies: 4
- Views: 172
Re: NH3
When NH3 interacts with H2O, it doesn't give up an H to H2O because H3O is very unstable. So rather, it will accept an H from H2O. The products would be NH4+ and OH-. Since it is accepting an H, which can be thought of as a proton, NH3 is an base and H2O is an acid.
- Sun Dec 06, 2020 10:15 pm
- Forum: Lewis Acids & Bases
- Topic: lewis vs bronsted
- Replies: 10
- Views: 381
Re: lewis vs bronsted
Lewis acids and bases focus on the transfer of lone pairs of electrons. Bronstead acids and bases focus on the transfer protons.
- Sun Dec 06, 2020 10:06 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Sapling 5
- Replies: 6
- Views: 351
Re: Sapling 5
(en) refers to ethylenediamine ligand, or NH2CH2CH2NH2. Ethylenediamine ligand is a bidentate ligand which has a coordination number of 2, and since there are 2 of en, the coordination number would 4. For CO, since there are 2 of it, it will form one ligand each as a monodentate, which will have a c...
- Sun Dec 06, 2020 9:30 pm
- Forum: *Molecular Orbital Theory Applied To Transition Metals
- Topic: Transition metals
- Replies: 11
- Views: 983
Re: Transition metals
The transition metals are elements in the d-block, which are groups 3-12. They also have valence electrons in at least two shells.
- Sun Dec 06, 2020 8:05 pm
- Forum: Naming
- Topic: sapling problem #1
- Replies: 5
- Views: 486
Re: sapling problem #1
You have most of the name correct. The only parts you have wrong in the name is the chlorine and the cobalt. Since there are 2 Cl anions in the backets, it would be dichloro instead of chloro. For the cobalt, it would be cobalt (III) because of the assigned charge. Since, we don't know the oxidation...
- Fri Nov 27, 2020 7:51 pm
- Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
- Topic: ionic liquids
- Replies: 8
- Views: 887
Re: ionic liquids
An ionic liquid is a salt in a liquid state. It has a low melting point
- Fri Nov 27, 2020 7:48 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: Dipole-Induced-Dipole and Dipole-Dipole
- Replies: 10
- Views: 767
Re: Dipole-Induced-Dipole and Dipole-Dipole
Dipole-dipole interactions occur when both molecules that are interacting with one another are polar all the time. Dipole-induced-dipole interactions occur when there is a polar molecule interacting with a nonpolar molecule.
- Fri Nov 27, 2020 7:41 pm
- Forum: Biological Examples
- Topic: Hemoglobin
- Replies: 13
- Views: 704
Re: Hemoglobin
Both hemoglobins and myoglobins are hemeproteins. However, hemoglobins are found in red blood cells and diffuses oxygen throughout the body. This oxygen goes through the blood and tissues of the body. Myoglobins are found in muscle cells, and they store oxygen in the muscle cells.
- Fri Nov 27, 2020 7:31 pm
- Forum: Bronsted Acids & Bases
- Topic: Main Difference
- Replies: 8
- Views: 574
Re: Main Difference
Lewis acid is when accept electrons, while lewis bases donate electrons. Bronsted acids accept hydrogen protons, while Bronsted bases donate hydrogen protons
- Fri Nov 27, 2020 7:28 pm
- Forum: Lewis Acids & Bases
- Topic: Molecules With Polar Double Bonds
- Replies: 5
- Views: 319
Re: Molecules With Polar Double Bonds
SO2, is a nonmetal oxide, which makes it a lewis acid. In addition, the shape of the SO2 is bent and it is polar. This causes the oxygen to attract more electrons, making it a lewis acid.
- Sun Nov 22, 2020 1:54 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Length vs Size of Molecule
- Replies: 14
- Views: 689
Re: Bond Length vs Size of Molecule
Although bond length definitely affects the strength of the bond, we also have to consider the intermolecular forces. Although both compounds only have LDF's. CCl4 has a higher boiling point than CH4 because it has stronger LDF interacting. This is due to it having more electron shells, which increa...
- Sun Nov 22, 2020 1:46 pm
- Forum: Dipole Moments
- Topic: Focus Problem 3F.1
- Replies: 5
- Views: 146
Re: Focus Problem 3F.1
First, I would draw out the lewis structures for all of the compounds. You know all of them have LDP. Next, I would check for hydrogen bonding. That only happens between H and O, N, or F. Dipole-dipole interactions occur when a partially negative part apolar molecule is attracted to a partially posi...
- Sun Nov 22, 2020 1:25 pm
- Forum: Bond Lengths & Energies
- Topic: electron repulsion
- Replies: 15
- Views: 689
Re: electron repulsion
Electron repulsion occurs when two of the same sign (negative and negative) come close to each other. They will repulse each other. Yes, electron repulsion does play a part in forming the shape of an atom.
- Sun Nov 22, 2020 1:20 pm
- Forum: Electronegativity
- Topic: Relationship between Dispersion and Electronegativity
- Replies: 6
- Views: 352
Re: Relationship between Dispersion and Electronegativity
Dispersion forces are forces between molecules; they hold the two molecules together. They are classified as intermolecular forces. Electronegativity is how often an atom attracts a shared pair of electrons, which connects two atoms together. Electronegativity determines intramolecular forces. Inter...
- Sun Nov 22, 2020 12:53 pm
- Forum: Octet Exceptions
- Topic: octet rule
- Replies: 8
- Views: 530
Re: octet rule
Cl has 17 electrons. It has 2 electrons in the first shell, 8 in the second shell, and 7 in the valence shell. The octet rule states that atoms will have 8 electrons in its valence electron. Cl will need one more electron to fill the valence shell and complete the octet rule. So 17 + 1 = 18 electrons.
- Sun Nov 15, 2020 7:29 pm
- Forum: Electronegativity
- Topic: Electronegativity
- Replies: 9
- Views: 396
Re: Electronegativity
@Maddie Turk
Yes, as the atomic radius increases, the electronegativity decreases. Because the electrons are further and further away from the nucleus of the element, the element becomes less active to attract electrons.
Yes, as the atomic radius increases, the electronegativity decreases. Because the electrons are further and further away from the nucleus of the element, the element becomes less active to attract electrons.
- Sun Nov 15, 2020 7:00 pm
- Forum: Resonance Structures
- Topic: Formal Charge
- Replies: 11
- Views: 453
Re: Formal Charge
Yes the more stable molecule/better lewis structure would be when the central atom has a formal charge that is or very close to zero.
- Sun Nov 15, 2020 7:00 pm
- Forum: Resonance Structures
- Topic: Formal Charge
- Replies: 11
- Views: 453
Re: Formal Charge
Yes the more stable molecule/better lewis structure would be when the central atom has a formal charge that is or very close to zero.
- Sun Nov 15, 2020 6:46 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: 2.A.13
- Replies: 5
- Views: 272
Re: 2.A.13
The electron that will removed is going to be from the last orbital of the element. Because this electron is furthest from the nucleus, it requires the least amount of energy to be removed. In order to find out which orbital the electron is being removed from, I would write out the electron configur...
- Sun Nov 15, 2020 5:32 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation Number
- Replies: 11
- Views: 532
Re: Oxidation Number
To find the oxidation number of the example you gave, first you need to set up an equation. Since the final charge of the molecule is given (-1), we can set that equal to the charges of the Cl and O. -1 = (Cl) + 4(O). For O, we can assume it has a -2 charge. So then, we can solve the charge for Cl. ...
- Sun Nov 15, 2020 4:02 pm
- Forum: Lewis Structures
- Topic: Sapling #4
- Replies: 8
- Views: 207
Re: Sapling #4
Hi, so for this problem, you have both structures correct. However for structure C, both O's (oxygens) should have a negative charge rather than C (carbon) having a negative charge. N (nitrogen) has the correct charge.
- Sun Nov 08, 2020 11:53 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Parallel electrons
- Replies: 7
- Views: 1289
Re: Parallel electrons
Electrons would be parallel when ground state electrons would fill two or more orbitals before pairing together in the same orbital. This means that the electrons in each orbital would have the same spin rather than when 2 electrons are in the same orbital and when they have opposite spins.
- Sun Nov 08, 2020 11:47 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy
- Replies: 7
- Views: 151
Re: Ionization Energy
The second ionization energy is greater than the first ionization energy because there are less electrons in the element. With one less electron, the remaining electron(s) will face a greater attraction/pull from the nucleus of the element. In order to remove the second electron that is experiencing...
- Sun Nov 08, 2020 11:42 pm
- Forum: Sigma & Pi Bonds
- Topic: pi bonds
- Replies: 8
- Views: 602
Re: pi bonds
Yes, a triple bond is considered one sigma bond and two pi bonds right
- Sun Nov 08, 2020 11:28 pm
- Forum: Sigma & Pi Bonds
- Topic: Hybridization for p
- Replies: 4
- Views: 232
Re: Hybridization for p
Pi bonds only have p hybridization and not spx because they can only form with p orbitals.
- Sun Nov 08, 2020 11:26 pm
- Forum: Ionic & Covalent Bonds
- Topic: Electronegativity
- Replies: 16
- Views: 905
Re: Electronegativity
Fluorine is the electronegative because it has 7 valence electrons. It only needs one more electron in order for it to have a noble gas configuration (electron octet). Therefore, it easily attracts electron and is highly reactive.
- Sun Nov 01, 2020 12:40 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing Equations Coefficient Question
- Replies: 24
- Views: 2357
Re: Balancing Equations Coefficient Question
If your equation has any stoichiometric coefficients that are fractions, you need to convert them to whole numbers. Since you can't have a fraction of a compound, you need to multiply whatever number on one side to the other as well in order for it to be balanced.
- Sun Nov 01, 2020 12:13 pm
- Forum: *Shrodinger Equation
- Topic: For Ms (spin up, spin down)
- Replies: 6
- Views: 521
Re: For Ms (spin up, spin down)
For +1/2, I think it is supposed to represent spin up, and -1/2 is supposed to represent spin down.
- Sun Nov 01, 2020 12:00 pm
- Forum: Ionic & Covalent Bonds
- Topic: Homework due date
- Replies: 49
- Views: 1898
Re: Homework due date
All of the Sapling hw and chem community posts are due at Sunday night at 11:59 pm.
- Sun Nov 01, 2020 11:57 am
- Forum: Einstein Equation
- Topic: E=pv and E=pc
- Replies: 6
- Views: 2003
Re: E=pv and E=pc
I think that those equations are derived from E = mc^2 and c = (λ)(v, frequency), P = (m)(v, velocity), and E = (h)(v, frequency)
- Sun Nov 01, 2020 1:07 am
- Forum: Properties of Light
- Topic: Is c always the speed of light?
- Replies: 92
- Views: 4737
Re: Is c always the speed of light?
For now, c will always be equal to the speed of light, which is 3x10^8 m/s.
- Sun Oct 25, 2020 10:16 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Stuck on Sapling HW
- Replies: 14
- Views: 1073
Re: Stuck on Sapling HW
The first step is to convert 3.39g of CuNO3 into moles. You can do this using the molar mass of CuNO3. Once you have converted the mass to moles, use the molarity equation (M = n/v) to solve for the volume. Make sure to convert to milliliters.
- Sun Oct 25, 2020 10:08 pm
- Forum: DeBroglie Equation
- Topic: n1 and n2
- Replies: 15
- Views: 636
Re: n1 and n2
In this case, n=1 would be the final energy and n=2 would be the initial energy level. In order for it to be less confusing, you can replace n1 and n2 with nfinal and ninitial
- Sun Oct 25, 2020 9:50 pm
- Forum: *Black Body Radiation
- Topic: Midterm 1
- Replies: 15
- Views: 758
Re: Midterm 1
No, Black Body radiation will not be on the midterm.
- Sun Oct 25, 2020 9:31 pm
- Forum: Properties of Light
- Topic: Amplitude
- Replies: 9
- Views: 465
Re: Amplitude
Amplitude is only used in the wave model. Increasing the amplitude means that there is a higher intensity. Decreasing the amplitude means that there is a lower intensity. With more a higher intensity, the brightness increases and vice versa. In order to change the energy, we have to change the frequ...
- Sun Oct 25, 2020 9:21 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Sapling #19
- Replies: 4
- Views: 267
Re: Sapling #19
Hi, so for this question, you still use the equation (delta momentum)(delta position) > or equal to (h/4pi). However, for delta momentum, change the mass to helium. In order for helium to match with the units in the equation, first change the molar mass from g/mol to kg/mol. Next, multiply it my Avo...
- Sun Oct 18, 2020 9:58 pm
- Forum: SI Units, Unit Conversions
- Topic: Metric Conversions
- Replies: 9
- Views: 1532
Re: Metric Conversions
There is an acronym:
King Henry Doesn’t Usually Drink Chocolate Milk
K- kilo
H- hecto
D- deca
U- base unit
D- deci
C- centi
M- milli
King Henry Doesn’t Usually Drink Chocolate Milk
K- kilo
H- hecto
D- deca
U- base unit
D- deci
C- centi
M- milli
- Sun Oct 18, 2020 9:49 pm
- Forum: Significant Figures
- Topic: How to deal with significant figures in decimals with zeros.
- Replies: 20
- Views: 1104
Re: How to deal with significant figures in decimals with zeros.
Once you have your answer, find the number with the least sig figs, and then apply the number of sig figs in that number to your answer.
- Sun Oct 18, 2020 9:41 pm
- Forum: *Shrodinger Equation
- Topic: Schrodinger for exam
- Replies: 20
- Views: 780
Re: Schrodinger for exam
I think the concept an how the equation is used is important for us and for the exam.
- Sun Oct 18, 2020 9:39 pm
- Forum: Properties of Light
- Topic: Chemistry Community Points
- Replies: 10
- Views: 384
Re: Chemistry Community Points
Hi! Yes, questions, comments, and replies are all counted as points. You need at least 5 of any of the three by Sunday at 11:59.
- Sun Oct 18, 2020 9:35 pm
- Forum: SI Units, Unit Conversions
- Topic: Do I need to do very single textbook question on the syllabus?
- Replies: 34
- Views: 1386
Re: Do I need to do very single textbook question on the syllabus?
I would because it just gives you a lot of practice. Doing all the problems, is however, really hard to do.
- Sat Oct 10, 2020 8:40 pm
- Forum: Empirical & Molecular Formulas
- Topic: Sapling Week 1 #8
- Replies: 23
- Views: 1216
Re: Sapling Week 1 #8
To find the molecular formula, count the number of carbons, hydrogens, and oxygens, respectively. The order of the elements in the molecular should be CHO. Once you have found the number of each element (C6H8O6), you can find find the molecular mass of the compound. The molar mass of carbon, hydroge...
- Sat Oct 10, 2020 8:09 pm
- Forum: Balancing Chemical Reactions
- Topic: Naming compounds
- Replies: 21
- Views: 1062
Re: Naming compounds
Hi!
Yeah I had the same problem too. What I suggest is to just go over the main chemical formulas (i.e. sulfide, bicarbonate, hydroxide, etc.). Those are kind of the basic formulas, but I don't think we are required to memorize anything more complicated than the examples.
Hope it helps!
Yeah I had the same problem too. What I suggest is to just go over the main chemical formulas (i.e. sulfide, bicarbonate, hydroxide, etc.). Those are kind of the basic formulas, but I don't think we are required to memorize anything more complicated than the examples.
Hope it helps!
- Sat Oct 10, 2020 8:01 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: HW E.15
- Replies: 4
- Views: 106
Re: HW E.15
The first step that I took to solve this problem was to figure out the mass of M. Since we know the mysterious compound has a molar mass of 74.10 g/mol and the molar mass of (OH)2, we can figure out the molar mass of M by subtracting 34.08 g/mol from 74.10 g/mol. This mass turns out to be 40.08g/mol...