Search found 103 matches
- Sun Mar 15, 2020 8:14 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Arrhenius eq
- Replies: 6
- Views: 406
Re: Arrhenius eq
When you want to know the effect on K with the change in temperature
- Sat Mar 14, 2020 11:24 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final exam structure
- Replies: 2
- Views: 280
Final exam structure
Does anyone know yet if the final will be multiple choice or will be free response?
- Sat Mar 14, 2020 12:46 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 6N.5
- Replies: 1
- Views: 170
6N.5
Can someone explain why/how in the answer key it says that since concentration of H+=10^pH, and the given pH is 4, which gives us a concentration of [10^-4]^16 (because the stoichiometric coefficient of H+=16) the end result is [10^66]? Wouldn’t it be [10^64]?
- Fri Mar 13, 2020 9:37 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6M.1
- Replies: 1
- Views: 167
6M.1
On homework question 6M.1 they are asking us to find the value of E(M2+/M). Im confused because they say we are given a standard Cu(s)|Cu2+ half cell, which I thought was an oxidation but when they give us the formed cell it’s actually on the right making it a reduction.When I look up its standard c...
- Thu Mar 12, 2020 10:44 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Homework question 7.1
- Replies: 2
- Views: 224
Homework question 7.1
Can someone please explain what the difference and meaning of “kinetic control” and “thermodynamic control”. I am not sure how to use those terms to answer the question they are asking.
- Sun Mar 08, 2020 10:56 pm
- Forum: General Rate Laws
- Topic: 7A.9
- Replies: 5
- Views: 326
Re: 7A.9
You first get the concentration by finding the Molar mass of N2O5 which is 108g, you then use the formula C=m/M*V and plug in the values they gave you in the problem.
- Sun Mar 08, 2020 10:22 pm
- Forum: General Rate Laws
- Topic: 7A.15
- Replies: 2
- Views: 218
7A.15
For homework problem 7A.15 how do we know which experiment to divide by? I thought that it was by the experiment with the largest initial rate is this true?
- Sun Mar 08, 2020 9:33 pm
- Forum: General Rate Laws
- Topic: 7A.11 part b
- Replies: 1
- Views: 163
7A.11 part b
Can someone explain how they answered part b to homework 7A.11?
- Sun Mar 08, 2020 4:56 pm
- Forum: General Rate Laws
- Topic: Fractional order and negative orders
- Replies: 3
- Views: 325
Fractional order and negative orders
Are we expected to know when to include a product into the rate law?
- Sun Mar 08, 2020 4:31 pm
- Forum: General Rate Laws
- Topic: Ammonia rate of consumption
- Replies: 1
- Views: 165
Ammonia rate of consumption
Why is the rate of consumption of NH3 solely equal to kr the (rate constant) and independent of the concentration of NH3?
- Sun Mar 01, 2020 10:26 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst equation and ph
- Replies: 2
- Views: 214
Nernst equation and ph
How can we derive the ph by using the Nernst equation? Would you have to use log rather than lnQ?
- Sun Mar 01, 2020 10:23 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Reducing/oxidizing agent
- Replies: 8
- Views: 529
Re: Reducing/oxidizing agent
The reducing agent will be the agent that pretty much causes another substance to reduce so in other words the agent that donates electrons, and the oxidizing agent will be the agent that accepts or gains electrons. I remember it as being the opposite from each other.
- Sun Mar 01, 2020 10:20 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Cell Diagram
- Replies: 4
- Views: 249
Re: Cell Diagram
Yes it is the same, the right side consist of the reduction reaction (cathode) and the left side consist of the oxidized reaction (anode)
- Fri Feb 28, 2020 1:43 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Non-Standard Potential
- Replies: 3
- Views: 257
Re: Non-Standard Potential
You can determine if the equilibrium constant of a reaction is greater than or less than one, by plugging all the necessary values into the Nernst equation, by doing this you can isolate lnK to one side in order to find what the value of K is. Usually if the voltage is positive, and the delta G is n...
- Fri Feb 28, 2020 1:40 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Concentration Cells
- Replies: 6
- Views: 503
Re: Concentration Cells
Both galvanic and concentration cells have a positive voltage, but the difference between both is that in concentration cells contain the same chemical species but in different concentrations, the difference in concentration drives movement of electrons, and the voltage tends to be very low. In galv...
- Sun Feb 23, 2020 3:25 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Concentration and cell potential
- Replies: 6
- Views: 398
Concentration and cell potential
Can someone please explain how concentration affects cell potential? And how Le Chatelliers principle plays a role in this?
- Sun Feb 23, 2020 3:23 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Max cell potential
- Replies: 1
- Views: 148
Max cell potential
Why is max cell potential directly related to the free energy difference between reactants and products in cell/redox reaction?
- Sun Feb 23, 2020 3:17 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Use of Platinum
- Replies: 10
- Views: 575
Re: Use of Platinum
You use platinum when there is no other metal solid being used, platinum is used to conduct these electrons.
- Sun Feb 23, 2020 3:11 pm
- Forum: Balancing Redox Reactions
- Topic: Alkaline reactions
- Replies: 2
- Views: 179
Re: Alkaline reactions
The main difference is that when balancing acidic solutions you balance oxygen with water and hydrogen with H+ protons, and in basic solutions you balance oxygen with OH- molecules and balance hydrogen with water.
- Sun Feb 23, 2020 3:07 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Redox reactions
- Replies: 4
- Views: 221
Re: Balancing Redox reactions
In acidic solutions you first balance oxygen with water an then balance the hydrogens with protons (H+).
- Thu Feb 13, 2020 4:36 pm
- Forum: Calculating Work of Expansion
- Topic: Positive or negative work
- Replies: 15
- Views: 2118
Re: Positive or negative work
If you have work being done on the system then work will be positive, and if work is being done by the system then work will be a negative value.
- Thu Feb 13, 2020 4:35 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: spontaneity
- Replies: 39
- Views: 1829
Re: spontaneity
If delta G (Gibbs free energy) is negative then you know that it was spontaneous.
- Thu Feb 13, 2020 4:33 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Intensive vs. Extensive
- Replies: 15
- Views: 1296
Re: Intensive vs. Extensive
Intensive properties do not depend on the quantity of matter , and expensive properties do depend on the amount of matter.
- Thu Feb 13, 2020 4:30 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: equilibrium concentrations
- Replies: 7
- Views: 498
Re: equilibrium concentrations
When calculating equilibrium concentrations we do not include the units in the brackets but concentration is measured using moles/liters.
- Thu Feb 13, 2020 4:26 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Midterm Curve
- Replies: 45
- Views: 2129
Re: Midterm Curve
Going off what happened in 14A and in his syllabus, he does not curve the midterm but a 50% in the class is a C, so in that way he does curve the final grade to help those that are close to failing.
- Sun Feb 09, 2020 10:44 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: spontaneity
- Replies: 18
- Views: 677
Re: spontaneity
It is a spontaneous reaction when delta G is negative, because it means that the free energy of the reactant is higher than the product.
- Sun Feb 09, 2020 10:41 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Midterm Material
- Replies: 10
- Views: 494
Re: Midterm Material
He mentioned in class that only the first page of outline 4 would be on the midterm.
- Sun Feb 09, 2020 10:29 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs Free Energy calculation
- Replies: 3
- Views: 219
Gibbs Free Energy calculation
Will we only be using the Gibbs change in free energy equation? And when do we know to use it instead of just G=H-TS?
- Sun Feb 09, 2020 10:12 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Entropy function
- Replies: 1
- Views: 48
Entropy function
How Is standard reaction entropy different from the entropy state function? Why is it considered an extensive property?
- Sun Feb 09, 2020 10:09 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Standard reaction enthalpy
- Replies: 2
- Views: 54
Standard reaction enthalpy
When you are calculating the standard enthalpy do you only use formation enthalpy or can you use bond enthalpies?
- Sun Feb 02, 2020 10:15 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: PLF sessions
- Replies: 6
- Views: 327
Re: PLF sessions
Yes you can, you would just have to email that PLF and ask them if you can attend their session :)
- Sun Feb 02, 2020 10:13 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Changing the energy of a system
- Replies: 9
- Views: 310
Re: Changing the energy of a system
I order to change the energy of a system you can do 3 things
1. Add or remove heat
2. Add or remove mass
3. Do work on the system
1. Add or remove heat
2. Add or remove mass
3. Do work on the system
- Sun Feb 02, 2020 10:11 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Steam burns
- Replies: 8
- Views: 258
Re: Steam burns
Steam releases more energy as opposed to boiling water, the steam releases about 40 kJ of energy.
- Sun Feb 02, 2020 9:46 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Negative Enthalpy
- Replies: 3
- Views: 79
Negative Enthalpy
Why do things that fo to a lower energy level happen by themselves?
- Sun Feb 02, 2020 9:34 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Internal Energy of isolated system
- Replies: 2
- Views: 62
Internal Energy of isolated system
In terms of delta U, why does it remain 0. Why does work + heat equal 0 in isolated systems?
- Sun Feb 02, 2020 9:14 pm
- Forum: Calculating Work of Expansion
- Topic: Constant Pressure
- Replies: 3
- Views: 109
Constant Pressure
Under what circumstances should you assume there is a constant pressure?
- Sun Jan 26, 2020 9:54 pm
- Forum: Phase Changes & Related Calculations
- Topic: Focus 4 Homework Questions
- Replies: 3
- Views: 85
Re: Focus 4 Homework Questions
I’d start with whatever addresses enthalpy first since we just learned about it on Wednesday.
- Sun Jan 26, 2020 9:53 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase changes: endothermic vs exothermic
- Replies: 12
- Views: 1122
Re: Phase changes: endothermic vs exothermic
Reverse reactions are exothermic because heat is not required, in fact heat is released when going in the reverse reaction.
- Sun Jan 26, 2020 9:49 pm
- Forum: Phase Changes & Related Calculations
- Topic: Work (w)
- Replies: 8
- Views: 327
Work (w)
Why is work not a state property and what are different types of work?
- Sun Jan 26, 2020 9:48 pm
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy
- Replies: 5
- Views: 171
Enthalpy
Why is enthalpy only a state property? Why does the path towards that state not matter?
- Sun Jan 26, 2020 6:39 pm
- Forum: Phase Changes & Related Calculations
- Topic: Why does steam cause burns?
- Replies: 29
- Views: 1114
Re: Why does steam cause burns?
Steam burns more because if you look at the diagram he showed us in lecture , it releases a lot more energy to go back down to its liquid phase. The release in energy is much more than if you touched boiling hot water.
- Thu Jan 16, 2020 11:18 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Combing kA and kB
- Replies: 2
- Views: 143
Combing kA and kB
Can anyone explain why we need to multiply the kA and kB in order the get the Kw for weak acid and base reactions?
- Thu Jan 16, 2020 11:15 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Inert Gas
- Replies: 7
- Views: 292
Re: Inert Gas
Inert gases are those gases that do not react, and therefore do not change the reaction, therefore you can use noble gases as an example as they usually do not react with other elements.
- Thu Jan 16, 2020 11:13 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Kw
- Replies: 16
- Views: 362
Re: Kw
They both essentially mean the same thing, and you can use them interchangeably.
- Thu Jan 16, 2020 9:30 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Exothermic
- Replies: 5
- Views: 244
Exothermic
Why is energy released as new bonds are formed?
- Thu Jan 16, 2020 9:20 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Endothermic vs exothermic
- Replies: 4
- Views: 161
Endothermic vs exothermic
Can someone please explain why : 1. If a reaction requires Heat, (is endothermic) while forming products, then heating will favor P (product) formation when additional heat is used. 2. If a reaction gives off heat, (is exothermic) while forming products, then heating will favor R formation when addi...
- Sun Jan 12, 2020 10:06 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K
- Replies: 10
- Views: 355
Re: K
Kc is the equilibrium constant used for aqueous solutions, because they have concentration values. Kp is the equilibrium constant for gases, since they have partial pressures.
- Thu Jan 09, 2020 4:57 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G.11
- Replies: 4
- Views: 178
5G.11
For question 5G.11 it asks to write the reaction quotient for the reactions given. I know that to calculate the Q you do the same thing as when you are calculating for K, but in the answer key it states that the Q= 1/(PBCl3)^2.
Why would it not be (PB2Cl4)(PHg2Cl2)/(Pcl3)^2(PHg)^2?
Why would it not be (PB2Cl4)(PHg2Cl2)/(Pcl3)^2(PHg)^2?
- Thu Jan 09, 2020 2:27 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G. 3
- Replies: 5
- Views: 151
Re: 5G. 3
Because it contains aqueous solution we would use Kc instead of Kp which is just for gases.
- Thu Jan 09, 2020 2:25 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q vs K
- Replies: 8
- Views: 193
Re: Q vs K
Q is not at equilibrium, it is just products over reactants at any given time during the reaction. K is the equilibrium constant of the products over her reactants.
- Thu Jan 09, 2020 2:22 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Re: Q and Ke: Small K value and Large K value
- Replies: 7
- Views: 262
Re: Q and Ke: Small K value and Large K value
The reaction quotient is the amount of products over reactants at any time during the Rxn, it is calculated the same way as K but it is not at equilibrium.
- Sun Dec 08, 2019 7:41 pm
- Forum: Student Social/Study Group
- Topic: Class Grading
- Replies: 44
- Views: 3515
Re: Class Grading
I hope this is true! But yeah I have heard that his final grades are curved but test aren’t.
- Sun Dec 08, 2019 12:26 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Ph and poH of weak acids
- Replies: 8
- Views: 405
Ph and poH of weak acids
Will we be asked to measure the ph and PoH of weak acids and bases?
- Sun Dec 08, 2019 12:25 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: CO2 in blood
- Replies: 1
- Views: 111
CO2 in blood
So if there is a lot of co2 in the blood it will cause there to be more carbonic acid in the blood which in turn creates more H30+ molecules increasing the pH?
- Sat Dec 07, 2019 4:20 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Titration
- Replies: 1
- Views: 149
Titration
Does anyone know what we will have to know about titrations? Or will that not be on the final?
- Sat Dec 07, 2019 4:18 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: 6D.11
- Replies: 1
- Views: 189
6D.11
For part a in 6D. 11 it asks whether an aqueous solution of each of the following salts has a pH equal to, greater than or less than 7. How would you determine this?
- Sun Dec 01, 2019 11:02 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acting as a base
- Replies: 1
- Views: 93
Acting as a base
Can any biological compound with a lone pair act as a base? Or is this only true for Nitrogen?
- Sun Dec 01, 2019 11:00 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Use of Bronsted or Lewis Definitions
- Replies: 7
- Views: 331
Re: Use of Bronsted or Lewis Definitions
You can use either one, but for now I would use the bronsted definition as it mentions protons which is what we are focusing on in this section.
- Sun Dec 01, 2019 10:58 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Amphoteric compounds
- Replies: 4
- Views: 152
Amphoteric compounds
What are amphoteric compounds and why are they important? Would h20 be considered an amphoteric compound?
- Sun Dec 01, 2019 10:56 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Difference between weak acids/bases and strong acids/bases
- Replies: 6
- Views: 387
Re: Difference between weak acids/bases and strong acids/bases
Strong acids and bases will fully ionize and disassociate while weak acids and bases will not fully ionize. Strong acids will produce more photons in solutions than weak acids.
- Sun Dec 01, 2019 10:54 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acids Vs. Bases
- Replies: 11
- Views: 840
Re: Acids Vs. Bases
I like to remember that if it is an acid it will donate protons, it is a proton donator. If it is a base it will be a proton acceptor.
- Sun Nov 24, 2019 10:52 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Transition metals
- Replies: 1
- Views: 94
Transition metals
Are only transition metals in the d block able to form ligand complexes?
- Sun Nov 24, 2019 10:49 pm
- Forum: Naming
- Topic: Trans and Cis
- Replies: 8
- Views: 464
Re: Trans and Cis
Yes, whenever you see that there are the same two molecules on the same side you will know it is cis, and if you see them on opposite sides it is trans.
- Sun Nov 24, 2019 10:43 pm
- Forum: Hybridization
- Topic: Shapes
- Replies: 3
- Views: 136
Re: Shapes
Specific shapes will tell you the amount of electronic density that is found. For example for Tetrahedral you have 4 regions of electron density regions, which means there will be 4 hybridization orbitals which is sp3.
- Sun Nov 24, 2019 10:39 pm
- Forum: Hybridization
- Topic: sigma or pi?
- Replies: 20
- Views: 1094
Re: sigma or pi?
Whenever you see a single bond know that it is sigma. When you see a double or triple bond one will be sigma and the other two will be pi bonds. Sigma bonds are single covalent bonds.
- Sun Nov 24, 2019 10:38 pm
- Forum: Hybridization
- Topic: Hybridization number
- Replies: 3
- Views: 262
Hybridization number
Will the hybridization orbitals always be equal to the number of electronic density regions? If yes, why?
- Thu Nov 21, 2019 9:44 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Week 8 homework
- Replies: 2
- Views: 221
Week 8 homework
Does anyone know if we can turn in homework this week on molecular structures since we have the test 2 on it this week?
- Sun Nov 17, 2019 10:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Double and triple bonds
- Replies: 4
- Views: 304
Double and triple bonds
I know that double and triple bonds are not considered double or triple regions of electron density, but why? Why do we not count them as such?
- Sun Nov 17, 2019 10:37 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 7
- Views: 422
Re: Bond Angles
Due to lone pair repulsion, the more lone pairs there are the more repulsion there will be.
- Sun Nov 17, 2019 10:33 pm
- Forum: Hybridization
- Topic: Test 2
- Replies: 11
- Views: 528
Re: Test 2
Dr. Lavelle mentioned in lecture that test 2 will not include hybridization.
- Sun Nov 17, 2019 10:31 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape
- Replies: 3
- Views: 185
Re: Molecular Shape
When you have 5 regions of electron density your electronic shape is Trigonal bipyramid, such as BrF3, but since in those regions two of those are lone pairs the molecular shape will be T shape. As for NH3, your regions of electronic density is 4 giving it an electronic shape of a tetrahedral, and s...
- Sun Nov 17, 2019 10:07 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E21 part d
- Replies: 1
- Views: 97
Re: 2E21 part d
In my discussion my TA said that it is sufficient to just write that the bond angles are less than 109.
- Sun Nov 10, 2019 6:46 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: Structure and bond type
- Replies: 2
- Views: 144
Structure and bond type
By just looking at a Lewis structure how can we distinguish the type of bond and dipole moment present?
- Sun Nov 10, 2019 6:44 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: Surface Area
- Replies: 2
- Views: 186
Surface Area
How does more surface area influence strength of bonds and boiling point?
- Sun Nov 10, 2019 6:25 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: Boiling point
- Replies: 5
- Views: 343
Boiling point
How does a molecules bond type relate to its boiling point? Which types of bonds will cause higher or lower boiling points?
- Sun Nov 10, 2019 6:17 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionization of Nitrogen vs Oxygen
- Replies: 11
- Views: 1534
Re: Ionization of Nitrogen vs Oxygen
Due to Nitrogen’s half filled orbitals, it makes it more stable and more difficult to remove and electron as opposed to oxygen which has two paired electrons.
- Sun Nov 03, 2019 8:19 pm
- Forum: Electronegativity
- Topic: which bond
- Replies: 4
- Views: 233
Re: which bond
If the electronegativity difference between the two elements is greater than or equal to 2.5 then it is a ionic bond, if the difference is equal to or below 1.5 it is a covalent bond. Basically the greater the difference in electronegativity the more pull on electrons one element will have over the ...
- Sun Nov 03, 2019 8:14 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: isoelectronic definition
- Replies: 7
- Views: 231
Re: isoelectronic definition
Isoelectric refers to elements that have the same amount of electrons, but have very different chemical characteristics.
- Sun Nov 03, 2019 8:09 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: What are the octet exceptions?
- Replies: 11
- Views: 481
Re: What are the octet exceptions?
Octet exceptions are the first 4 elements in the periodic table which are; H,He,Li, and Be, as they will never have a full octet. An exception to this octet guideline are all elements after Neon, so in the 3p block and on, these elements are allowed to have more than 8 electrons, they don’t have to ...
- Sun Nov 03, 2019 8:06 pm
- Forum: Lewis Structures
- Topic: Which element at center of the structure
- Replies: 6
- Views: 498
Re: Which element at center of the structure
The element with the lowest ionization energy will always be in the middle, but hydrogen will never be in the middle. Just look at your periodic table and remember that the ionization energy increases as you go across the periodic table (left to right)
- Sun Nov 03, 2019 8:04 pm
- Forum: Lewis Structures
- Topic: Resonance Structure
- Replies: 4
- Views: 252
Re: Resonance Structure
If asked for a Lewis structure for an element with multiple variations (resonance) you have to include the resonance structures and indicate that there is a hybridization of the the structure, which will be a a combination of the resonance structures. To be safe I would always include it.
- Sun Oct 27, 2019 7:41 pm
- Forum: Trends in The Periodic Table
- Topic: Electron affinity equation
- Replies: 1
- Views: 66
Electron affinity equation
Can someone explain why in order to find the electron affinity, you need to subtract the energy of the neutral atom from the energy of the final. Thank you.
- Sun Oct 27, 2019 7:38 pm
- Forum: Ionic & Covalent Bonds
- Topic: Writing Electron Configurations for an Ion
- Replies: 6
- Views: 268
Re: Writing Electron Configurations for an Ion
When writing the electron configuration of an ion, it changes from that of its parent element because you are changing the number of electrons in the element. When writing the change configuration you have to look at the charge of the ion, if its a positive charge it means that electrons were remove...
- Sun Oct 27, 2019 7:34 pm
- Forum: Lewis Structures
- Topic: Clarification
- Replies: 6
- Views: 196
Re: Clarification
In the lecture Professor Lavelle states that obtaining a formal charge of 0 is much more important than following the octet rule.
- Sun Oct 27, 2019 7:32 pm
- Forum: Ionic & Covalent Bonds
- Topic: Resonance
- Replies: 10
- Views: 379
Re: Resonance
Resonance just means you can write a Lewis structure in different ways, you can write bonds in different ways, but it is still the same molecule.
- Sun Oct 27, 2019 7:30 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Bonds
- Replies: 11
- Views: 522
Re: Covalent Bonds
Covalent bonds can only be formed by nonmetals, and metals are more likely to form ionic bonds. Remember that metals often times become cations because it is easier for them to give up electrons. Non metals have high ionization energy.
- Sun Oct 20, 2019 12:06 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Radiation Type
- Replies: 5
- Views: 169
Re: Radiation Type
Since there was a question in the homework which asked to name the types of light/radiation from highest to lowest energy, I am assuming we will be tested on it and expected to memorize them, that would be my safest guess.
- Sun Oct 20, 2019 12:02 am
- Forum: Properties of Light
- Topic: Unit for Wavelength
- Replies: 34
- Views: 2297
Re: Unit for Wavelength
It is measured in meters, it is a distance. You can give it in picometers, and nanometers as well.
- Sat Oct 19, 2019 11:44 pm
- Forum: Photoelectric Effect
- Topic: One photon one atom interaction
- Replies: 14
- Views: 533
Re: One photon one atom interaction
After increasing the frequency and the threshold of the electrons being met, in order to have more electrons being ejected you can then increase the intensity as it produces more photons at this energy, which increases photon, electron interactions. But remember that this will not change the amount ...
- Sat Oct 19, 2019 11:41 pm
- Forum: Photoelectric Effect
- Topic: Intensity of Light
- Replies: 5
- Views: 168
Re: Intensity of Light
When you increase the intensity of light you are only increasing the number of photons being emitted, this does not increase the energy that each photon emits. In order to have electrons be released from metal, the energy of each individual photon must be high enough to pass the energy threshold and...
- Sat Oct 19, 2019 11:39 pm
- Forum: Properties of Light
- Topic: 1A.9 Energy of Photon
- Replies: 12
- Views: 434
Re: 1A.9 Energy of Photon
After you find the wavelength of the radiation, you then find the energy by using E=h*v, which is Plancks constant 6.626x10^-34J times frequency which is given. Hope this helps!
- Sat Oct 19, 2019 11:35 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Spin up and spin down
- Replies: 13
- Views: 1058
Spin up and spin down
I am having a hard time understanding the concept of different spin states in electrons, I never learned this in High school chem. Can anyone explain how we know if an electron is in a spin up or spin down state?
- Sat Oct 19, 2019 11:27 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Electron States
- Replies: 3
- Views: 121
Electron States
What did Professor Lavelle mean when he said that an electron is in a particular state, not in a specific orbital? I am having a hard time understanding this concept.
- Sat Oct 12, 2019 10:42 pm
- Forum: Properties of Electrons
- Topic: Electron Energy Levels
- Replies: 8
- Views: 316
Re: Electron Energy Levels
From what I recall Professor Lavelle saying is that each atom has unique electronic structures and energy levels, which is why they can only absorb or emit unique frequencies that are allowed by their unique structures.
- Sat Oct 12, 2019 10:37 pm
- Forum: Photoelectric Effect
- Topic: Wave-like Properties
- Replies: 4
- Views: 132
Re: Wave-like Properties
What I got from lecture was that the larger the mass the smaller the wavelength properties making it not detectable. So anything less that 10^-15m does not have detestable wavelength properties.
- Sat Oct 12, 2019 10:35 pm
- Forum: Photoelectric Effect
- Topic: 1B.7 part b
- Replies: 1
- Views: 86
Re: 1B.7 part b
For part b you are asked to find the energy emitted by 5 mg of Sodium atoms. You first have to find the number of moles in 5mg of Na, you then take this number and calculate the energy by multiplying the number of moles in 5mg of Na by Avogrado’s constant over 1 mole, you then multiple that by what ...
- Sat Oct 12, 2019 10:26 pm
- Forum: Photoelectric Effect
- Topic: Classic Wave in Photoelectric effect
- Replies: 5
- Views: 234
Classic Wave in Photoelectric effect
Why does does the the model equation Ek=1/2Me-ve^2 not change when you increase intensity? How is this different from the wave model?
- Sat Oct 12, 2019 9:58 pm
- Forum: Photoelectric Effect
- Topic: Removing electrons in Photoelectric concept
- Replies: 2
- Views: 56
Removing electrons in Photoelectric concept
In lecture we went over the photoelectric effect, and I understood that if an incoming photon does not have the energy needed to remove an electron, and electron won’t be ejected. My question is what is that threshold that the photon should hit? What energy level are we comparing it to and why?
- Wed Oct 02, 2019 11:20 pm
- Forum: Empirical & Molecular Formulas
- Topic: Clarification on the Vitamin C Example
- Replies: 6
- Views: 245
Re: Clarification on the Vitamin C Example
I believe this was because we are supposed to round up.
- Wed Oct 02, 2019 11:18 pm
- Forum: Empirical & Molecular Formulas
- Topic: HW 1 Problem F.9
- Replies: 7
- Views: 439
Re: HW 1 Problem F.9
Yes, the empirical formula is the ratio of elements, unlike the molecular formula which gives you the exact numbers of elements in a compound.