Search found 100 matches
- Sun Mar 15, 2020 8:47 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Doing work vs work done
- Replies: 8
- Views: 695
Re: Doing work vs work done
W is positive when work is being done ON the system and negative when the system is doing the work.
- Sun Mar 15, 2020 8:45 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Affecting E cell
- Replies: 4
- Views: 419
Re: Affecting E cell
If the reaction was at equilibrium, changing the concentrations will shift the equilibrium and change from standard E cell to E cell.
- Sun Mar 15, 2020 8:43 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Fast Reactions
- Replies: 4
- Views: 404
Re: Fast Reactions
If the reaction is very fast, the rate changes more rapidly than the time required to measure it. The reaction may be finished before an initial rate can be observed.
- Sun Mar 15, 2020 8:41 pm
- Forum: General Rate Laws
- Topic: Overall Order
- Replies: 6
- Views: 437
Re: Overall Order
Add the exponents of all the reactants in the rate equation.
- Mon Mar 09, 2020 3:03 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: HW 7D.5
- Replies: 2
- Views: 230
HW 7D.5
What are the correct units for the answer? In the textbook, it's
2.7x10^10 mol.L-1.s-1 and in the solutions manual it's 2.7x10^10 L.mol-1.s-1
2.7x10^10 mol.L-1.s-1 and in the solutions manual it's 2.7x10^10 L.mol-1.s-1
- Sun Mar 08, 2020 10:35 pm
- Forum: General Rate Laws
- Topic: 7A.7 Units of Rate Constants
- Replies: 2
- Views: 244
Re: 7A.7 Units of Rate Constants
Organic Chem tutor used k=M^(1-n).s^-1.
- Sun Mar 08, 2020 10:32 pm
- Forum: General Rate Laws
- Topic: Changing the mass of electrodes
- Replies: 6
- Views: 400
Re: Changing the mass of electrodes
Mass doesn't affect the E(cell) but concentration does.
- Sun Mar 08, 2020 10:24 pm
- Forum: General Rate Laws
- Topic: Rate constant vs. rate
- Replies: 4
- Views: 312
Re: Rate constant vs. rate
You can use rate constant to calculate the rate. Rate constant doesn't change while rate does.
- Sun Mar 08, 2020 10:19 pm
- Forum: General Rate Laws
- Topic: 7B3a
- Replies: 3
- Views: 333
Re: 7B3a
0.693 came from ln(2) which is in the half life equation for first order reactions. t=ln(2)/k
- Sun Mar 08, 2020 10:18 pm
- Forum: General Science Questions
- Topic: Worksheets for Final Review Sessions
- Replies: 2
- Views: 353
Re: Worksheets for Final Review Sessions
You can search up some of the TAs names on Chem Com, go to step-up, or workshops.
- Sun Mar 01, 2020 8:26 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst Equation
- Replies: 3
- Views: 314
Re: Nernst Equation
You derive it from the equations: ΔG=ΔG°+RT(ln(Q)) and ΔG=-nFE. You set the two equal to each other to get: -nFE=ΔG°+RT(ln(Q)). Divide both sides by -nF to get: E=(ΔG°/-nF)-RT(ln(Q))/nF) From ΔG°=-nFE°, you change it to E°=ΔG°/-nF to replace the first part of the equation to get: E=E°-(RT/nF) x ln(Q)
- Sun Mar 01, 2020 8:03 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagrams
- Replies: 6
- Views: 491
Cell Diagrams
When we write cell diagrams, and there are two ions ex: Fe2+ and Fe3+ both in aqueous solution. I know you don't separate it with the line (|) and instead, you separate it with a comma. But does it matter what order I write them in? Can I write them as either Fe2+,Fe3+ OR Fe3+,Fe2+?
- Sun Mar 01, 2020 7:59 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: delta G=-nFE
- Replies: 7
- Views: 544
Re: delta G=-nFE
You can find it by balancing the electrons of the half-reactions and that's the n, the amount in moles of electrons that were transferred.
- Sun Mar 01, 2020 7:58 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: How to tell what rxn to use
- Replies: 2
- Views: 298
Re: How to tell what rxn to use
If you write out the original reaction, you can see that the oxidation number of Cl doesn't change whereas Fe does.
- Sat Feb 29, 2020 12:07 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: HW 6L.7 (c)
- Replies: 1
- Views: 212
HW 6L.7 (c)
Problem asks to write the half-reactions and devise a galvanic cell (write a cell diagram) to study each of the following reactions. (c) Cd(s) + 2Ni(OH)3(s) --> Cd(OH)2(s) + 2Ni(OH)2(s), the reaction in nickel-cadmium cell I found the two half-reactions which were: Cd(s) + 2OH-(aq) --> Cd(OH)2 + 2e-...
- Sun Feb 23, 2020 7:49 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Is this course curved?
- Replies: 7
- Views: 577
Re: Is this course curved?
It's 50% to get a C- in the class and he probably rounds your grade at the end if you're really close.
- Sun Feb 23, 2020 7:47 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2
- Replies: 15
- Views: 954
Test 2
Is test 2 just going to include the material that wasn't tested on the midterm up to what we learn before the test?
- Sun Feb 23, 2020 7:43 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: chemistry community posts
- Replies: 12
- Views: 677
Re: chemistry community posts
Our TA said that there's a system that automatically checks your chemistry community posts.
- Sun Feb 23, 2020 7:38 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Le Chatelier's Principle
- Replies: 1
- Views: 216
Le Chatelier's Principle
How does Le Chatelier's Principle apply to cell potentials?
- Sun Feb 23, 2020 7:35 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: cell diagrams
- Replies: 5
- Views: 370
cell diagrams
How do you write the redox reaction or draw cell diagrams when you're given two half-reactions?
- Sun Feb 16, 2020 9:43 pm
- Forum: Administrative Questions and Class Announcements
- Topic: HW7
- Replies: 14
- Views: 848
Re: HW7
Probably anything from the end of thermodynamics and beginning of electrochemistry.
- Sun Feb 16, 2020 7:46 pm
- Forum: Van't Hoff Equation
- Topic: Van't Hoff Equation
- Replies: 3
- Views: 201
Van't Hoff Equation
When would you use the Van't Hoff Equation and what does it mean?
- Sun Feb 16, 2020 7:43 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: delta S=qrev/t
- Replies: 4
- Views: 308
Re: delta S=qrev/t
Sometimes it's given to you and other times, you're given the information to calculate it.
- Sun Feb 16, 2020 7:42 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: delatG= -RTInK
- Replies: 4
- Views: 589
Re: delatG= -RTInK
Because it relates the difference in Standard Gibbs Free Energy to K.
- Sun Feb 16, 2020 7:34 pm
- Forum: Calculating Work of Expansion
- Topic: Work Equation
- Replies: 6
- Views: 645
Re: Work Equation
Work under constant volume is 0. Under constant pressure, you'd use w=-P(external)Delta V. Under constant temperature when it's reversible and isothermal, you'd use w=-nRTln(Vf/Vi).
- Sun Feb 09, 2020 9:44 pm
- Forum: Calculating Work of Expansion
- Topic: 4A.9
- Replies: 2
- Views: 201
Re: 4A.9
the final temperature would be the same so you set qCu=-qWater and solve.
- Tue Feb 04, 2020 11:45 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Question 4.C.9
- Replies: 1
- Views: 130
Re: Question 4.C.9
For Part 1) You would calculate the heat (q) required to heat the copper kettle and water to 100 C separately. Then you add them together to find the total heat needed to raise the temperature. Use q=nCdeltaT for both. For Part 2) You would divide the heat required to heat the water by the total hea...
- Tue Feb 04, 2020 11:12 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: closed system
- Replies: 7
- Views: 391
Re: closed system
Since it's sealed, no matter can be removed or added but heat can still be transferred so it's a closed sytem.
- Tue Feb 04, 2020 11:11 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy
- Replies: 2
- Views: 125
Re: Enthalpy
These changes occur when reactions require energy or release energy.
- Tue Feb 04, 2020 11:09 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Ideal Gas Heat Capacities
- Replies: 1
- Views: 100
Re: Ideal Gas Heat Capacities
I think it'd be a good idea to know them and how to apply it since Lavelle did assign the reading so it's fair game.
- Sun Feb 02, 2020 9:28 pm
- Forum: Calculating Work of Expansion
- Topic: 4A.5
- Replies: 2
- Views: 163
Re: 4A.5
It means that the constant temperature of the gas is maintained by ensuring that the system is in thermal contact with a constant-temperature water bath at all stages of the expansion. In an isothermal expansion, the pressure of the gas falls as it expands; therefore, to achieve reversible expansion...
- Sun Feb 02, 2020 9:20 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4A.13
- Replies: 2
- Views: 111
Re: 4A.13
In the first equation, you're calculating for the heat capacity of the Calorimeter using the heat put into the Calorimeter which is why it's qcal. In the second equation, you use it to calculate the heat of the overall change in internal energy from the 2 rises in temperature.
- Sun Feb 02, 2020 9:16 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Changing the energy of a system
- Replies: 9
- Views: 357
Re: Changing the energy of a system
The three ways to change the energy of a system is heat, work, and mass flow.
- Sun Feb 02, 2020 9:12 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4B.5
- Replies: 3
- Views: 138
4B.5
An ideal gas in a cylinder was placed in a heater and gained 5.50 kJ of energy as heat. If the cylinder increased in volume from 345 mL to 1846 mL against an atmospheric pressure of 750. Torr during this process, what is the change in internal energy of the gas in the cylinder?
How do we solve this?
How do we solve this?
- Sun Feb 02, 2020 6:07 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4A.13
- Replies: 3
- Views: 116
4A.13
Problem: A constant-volume calorimeter was calibrated by carrying out a reaction known to release 3.50 kJ of heat in 0.200 L of solution in the calorimeter (q 5 23.50 kJ), resulting in a temperature rise of 7.32 C. In a subsequent experiment, 100.0 mL of 0.200 m HBr(aq) and 100.0 mL of 0.200 m KOH(a...
- Sun Jan 26, 2020 9:18 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5% Rule
- Replies: 9
- Views: 372
Re: 5% Rule
If X is less than 5% of the initial, you should be on the right track!
- Sun Jan 26, 2020 9:16 pm
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy Calculations
- Replies: 5
- Views: 151
Re: Enthalpy Calculations
I think it's helpful to know the generic formulas for liquid to vapor, solid to liquid, and solid to vapor which make up the formula (Delta H sublimation)=(Delta H fusion) + (Delta H vapor).
- Sun Jan 26, 2020 9:13 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Exothermic and Endothermic
- Replies: 11
- Views: 780
Re: Exothermic and Endothermic
Exothermic reactions have a negative value because it releases energy so products are lower than reactants. Vice versa for endothermic reactions which have a positive value because it requires energy so the reactants are lower than the products.
- Sun Jan 26, 2020 9:10 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Meaning of State Function
- Replies: 8
- Views: 245
Re: Meaning of State Function
A state function is not dependent on the path taken to obtain that state. One example is density which only depends on the initial and final, not the path taken.
- Sun Jan 26, 2020 9:07 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Negative Square Root solving an ICE box
- Replies: 13
- Views: 606
Re: Negative Square Root solving an ICE box
Usually, you shouldn't get a negative number inside the square root. Outside the square root, it can be positive and negative.
- Sun Jan 19, 2020 8:23 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm and final
- Replies: 6
- Views: 273
Re: Midterm and final
I think the midterm and final is cumulative but not the tests.
- Sun Jan 19, 2020 8:19 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs Q
- Replies: 14
- Views: 421
Re: K vs Q
K is used when a reaction is at equilibrium. Q can be used at any arbitrary stage of a reaction.
- Sun Jan 19, 2020 8:12 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: exothermic/endothermic rxns
- Replies: 4
- Views: 184
Re: exothermic/endothermic rxns
Raising the temperature of an exothermic reaction lowers the K value and shifts to favor the production of reactants. On the other hands, raising the temperature of an endothermic reaction raises the K value and shifts to favor the production of products.
- Sun Jan 19, 2020 8:06 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5%
- Replies: 4
- Views: 192
Re: 5%
You're allowed to approximate X while doing ICE tables if the K constant is less than 1.0x10^-3. If the answer is less than 5% of the initial molarity, then the approximation is okay.
- Sun Jan 19, 2020 8:03 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Shift Of Reaction
- Replies: 4
- Views: 244
Re: Shift Of Reaction
A reaction shifts left or right in order to reach equilibrium again if something such as concentration or temperature changed.
- Sun Jan 12, 2020 9:14 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Calculating for Pressure
- Replies: 5
- Views: 213
Re: Calculating for Pressure
Usually, temperature should be given so you can use PV=nRT to solve for pressure.
- Sun Jan 12, 2020 9:00 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Partial Pressure
- Replies: 19
- Views: 771
Re: Partial Pressure
It should be given usually.
- Sun Jan 12, 2020 8:54 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's Principle
- Replies: 5
- Views: 248
Le Chatelier's Principle
What exactly is Le Chatelier's Principle?
- Sun Jan 12, 2020 6:25 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: memorization
- Replies: 12
- Views: 628
Re: memorization
I don't think so, we should be given it on exams.
- Sun Jan 12, 2020 6:17 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q>K
- Replies: 9
- Views: 329
Re: Q>K
When there is more product than reactants and the reverse reaction is favored.
- Sun Dec 08, 2019 10:26 pm
- Forum: *Titrations & Titration Calculations
- Topic: Type of Titration
- Replies: 3
- Views: 568
Re: Type of Titration
If the pH of the titration is >7, it's basic. If it's <7, it's basic. If pH is 7, it's neutral.
- Sun Dec 08, 2019 10:20 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Uncertainty
- Replies: 5
- Views: 365
Re: Uncertainty
Delta X is the uncertainty in position.
- Sun Dec 08, 2019 10:18 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Types of Salts
- Replies: 7
- Views: 642
Re: Naming
use these when the ligand already has a prefix of bi- tri- tetra- etc.
- Wed Dec 04, 2019 10:39 pm
- Forum: Naming
- Topic: Naming Compounds
- Replies: 2
- Views: 160
Naming Compounds
When we name coordination compounds on the final, would writing (en) in place of ethylenediamine or (dien) in place of diethylenetriamine be acceptable?
- Sun Dec 01, 2019 10:40 pm
- Forum: General Science Questions
- Topic: Bruincasts
- Replies: 9
- Views: 791
Re: Bruincasts
Lavelle doesn't bruincast his lectures but his website does have modules that you might find helpful.
- Sun Dec 01, 2019 10:37 pm
- Forum: Lewis Acids & Bases
- Topic: Weak vs. Strong
- Replies: 8
- Views: 745
Re: Weak vs. Strong
Strong acids completely ionize in solution while strong bases completely ionize in water.
- Sun Dec 01, 2019 10:29 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Acid strength relative to kA
- Replies: 2
- Views: 163
Re: Acid strength relative to kA
Stronger acids have higher kA and lower pKA while weaker acids have lower kA and higher pKA.
- Sun Dec 01, 2019 10:27 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Equilibrium constants
- Replies: 3
- Views: 165
Re: Equilibrium constants
The equilibrium constant kA is a quantitative measure of the strength of an acid in a solution. The pKa is used to indicate the strength of an acid.
- Sun Dec 01, 2019 10:11 pm
- Forum: Student Social/Study Group
- Topic: Studying for Final
- Replies: 7
- Views: 766
Re: Studying for Final
Go to Lyndon's review sessions!
- Sun Nov 24, 2019 10:20 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: bronsted acid
- Replies: 5
- Views: 292
Re: bronsted acid
A bronsted acid is a substance that gives up or donates hydrogen ions during a chemical reaction.
- Sun Nov 24, 2019 10:17 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Final
- Replies: 10
- Views: 603
Re: Final
Yes, Lavelle has mentioned in class before that the final will be cumulative of everything we've learned this quarter.
- Sun Nov 24, 2019 10:13 pm
- Forum: Hybridization
- Topic: Bond Strength
- Replies: 2
- Views: 165
Re: Bond Strength
As the orbitals in the bond have more s character, the bond length generally decreases so the strength increases.
Re: 9C. 3
K3[Cr(CN)6]
- Tue Nov 19, 2019 9:38 pm
- Forum: Student Social/Study Group
- Topic: Lydon's Week 8 Learning Session
- Replies: 4
- Views: 370
Lydon's Week 8 Learning Session
Does anyone have the answers to Lydon's worksheet this week?
- Sun Nov 17, 2019 7:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Repulsion strength and Bond Angles
- Replies: 12
- Views: 732
Re: Repulsion strength and Bond Angles
Yes because the molecule with the lone pair would create repulsion that would alter the degrees of the bond angles.
- Sun Nov 17, 2019 7:08 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Electronic arrangement vs molecular shape
- Replies: 4
- Views: 219
Re: Electronic arrangement vs molecular shape
The electronic arrangement factors in both bonding pairs and lone pairs. The molecular shape takes into consideration of the lone pairs. So an atom's electronic arrangement and molecular shape can be the same if there aren't any lone pairs.
- Sun Nov 17, 2019 7:00 pm
- Forum: Photoelectric Effect
- Topic: Evidence of Waves Having Properties of Matter
- Replies: 1
- Views: 217
Re: Evidence of Waves Having Properties of Matter
The Davisson–Germer experiment confirmed the de Broglie hypothesis that matter has wave-like behavior.
- Sun Nov 17, 2019 6:54 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Angles
- Replies: 4
- Views: 329
Re: VSEPR Angles
The areas of electron density and lone pairs affect bond angles while atomic radius affects the bond length.
- Sun Nov 17, 2019 4:58 pm
- Forum: Trends in The Periodic Table
- Topic: trends on test 2
- Replies: 4
- Views: 299
Re: trends on test 2
Test 2 will cover anything that wasn't tested on the midterm up to sigma and pi bonds which he will discuss in class on Monday I believe.
- Sun Nov 10, 2019 10:34 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation Number
- Replies: 6
- Views: 436
Re: Oxidation Number
The oxidation number of an atom is the charge that an atom would have if the compound was composed of ions. The oxidation number of each atom can be calculated by subtracting the sum of lone pairs and electrons it gains from bonds from the number of valence electrons.
- Sun Nov 10, 2019 10:32 pm
- Forum: Octet Exceptions
- Topic: electron number in octet
- Replies: 8
- Views: 629
Re: electron number in octet
It depends on what element it is. Common examples of elements that can form an expanded octet is sulfur, phosphorus, silicon, and chlorine.
- Sun Nov 10, 2019 10:13 pm
- Forum: Electronegativity
- Topic: Electron affinity
- Replies: 6
- Views: 763
Re: Electron affinity
Electronegativity measures the tendency of an atom to attract a bonding pair of electrons. Electron affinity is the change in energy of a neutral atom when an electron is added to the atom to form a negative ion. Electron affinity and electronegativity both increase from left to right in a period an...
- Sun Nov 10, 2019 10:03 pm
- Forum: Student Social/Study Group
- Topic: Chem 14B
- Replies: 10
- Views: 769
Re: Chem 14B
I think I am if I get the class!
- Sun Nov 10, 2019 1:55 pm
- Forum: Electronegativity
- Topic: Ionization energy of O vs N
- Replies: 6
- Views: 1819
Re: Ionization energy of O vs N
The ionization energy trend in the periodic table has a few exceptions with oxygen and nitrogen being one of them. The ionization energy of oxygen is lower than nitrogen because each p-orbital in a nitrogen atom is occupied by one electron but in oxygen, the first orbital is occupied by a pair of el...
- Sun Nov 03, 2019 9:02 pm
- Forum: Electronegativity
- Topic: Defining electronegativity
- Replies: 6
- Views: 855
Re: Defining electronegativity
Electronegativity is a measure of how strongly atoms attract bonding electrons to themselves.
- Sun Nov 03, 2019 8:54 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Aufbau vs Hunds
- Replies: 6
- Views: 523
Re: Aufbau vs Hunds
The Aufbau principle states that lower energy orbitals fill before higher energy orbitals. Hund's Rule states that one electron goes into each orbital until all of them are half full before pairing up.
- Sun Nov 03, 2019 8:44 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration for cations
- Replies: 3
- Views: 184
Re: Electron Configuration for cations
Yes, you remove an electron from the highest energy level.
- Sun Nov 03, 2019 8:42 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 4s or 3d first?
- Replies: 14
- Views: 878
Re: 4s or 3d first?
My TA said that we should write 3d first so the shells are in chronological order.
- Sun Nov 03, 2019 1:23 pm
- Forum: Lewis Structures
- Topic: Central Atom
- Replies: 3
- Views: 103
Re: Central Atom
The central atom is usually the least electronegative atom with the most unpaired valence electrons. If carbon is present, often times, the central atom is carbon. However, hydrogen can never be a central atom.
- Sun Oct 27, 2019 8:43 pm
- Forum: Ionic & Covalent Bonds
- Topic: What is the difference between an anion and cation?
- Replies: 7
- Views: 872
Re: What is the difference between an anion and cation?
The net electrical charge of an anion is negative and a cation is positive. For example, sulfate is an anion and ammonium is a cation.
- Sun Oct 27, 2019 8:31 pm
- Forum: Lewis Structures
- Topic: Orbitals
- Replies: 9
- Views: 518
Re: Orbitals
Usually, you remove electrons from the farthest orbital so yes, you do.
- Sun Oct 27, 2019 8:05 pm
- Forum: Ionic & Covalent Bonds
- Topic: Metalloids
- Replies: 5
- Views: 231
Re: Metalloids
Metalloids can form covalent and ionic bonds. They can form covalent bonds by sharing electrons or ionic bonds by either losing or gaining electrons.
- Sun Oct 27, 2019 8:00 pm
- Forum: Lewis Structures
- Topic: Choosing the central atom
- Replies: 16
- Views: 805
Re: Choosing the central atom
Dr. Lavelle said during lecture to use the least electronegative atom as the central atom. In the case that carbon is present in the ion, it's usually the central atom.
- Sun Oct 27, 2019 7:56 pm
- Forum: Electronegativity
- Topic: Electronegativity
- Replies: 14
- Views: 681
Re: Electronegativity
Electronegativity describes the likelihood of an atom to attract a shared pair of electrons towards itself. It increases from left to right because of a greater charge on the nucleus which causes the electron bonding pairs to be attracted to atoms placed further right on the periodic table.
- Sun Oct 20, 2019 11:01 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: What is electron configuration?
- Replies: 3
- Views: 191
Re: What is electron configuration?
Electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals. It tells you how many electrons there are in each of the different orbitals and at which energy level.
- Sun Oct 20, 2019 8:49 pm
- Forum: Properties of Light
- Topic: What are the units of hertz
- Replies: 41
- Views: 2228
Re: What are the units of hertz
The unit for hertz is the number of cycles per second which basically measures frequency.
- Sun Oct 20, 2019 8:37 pm
- Forum: Limiting Reactant Calculations
- Topic: general questions
- Replies: 11
- Views: 1049
Re: general questions
Finding the limiting reactant helps to determine the amount of a product that can be produced or how much of a reactant will react with the limiting reactant.
- Sun Oct 20, 2019 8:31 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Pauli Exclusion Principle
- Replies: 9
- Views: 932
Re: Pauli Exclusion Principle
It basically says that in an atom or a molecule, 2 electrons can’t have the same four electronic quantum numbers. The two electrons in an orbital must have opposite spins.
- Thu Oct 17, 2019 7:50 pm
- Forum: DeBroglie Equation
- Topic: the m in the de broglie equation
- Replies: 5
- Views: 157
Re: the m in the de broglie equation
yes, m is the mass of the particle.
- Sun Oct 13, 2019 10:30 pm
- Forum: Trends in The Periodic Table
- Topic: Element Names
- Replies: 8
- Views: 1049
Re: Element Names
You should be using the periodic table on Lavelle's website to familiarize yourself with it since that's the one we'll be using on all of our tests.
- Sun Oct 13, 2019 10:23 pm
- Forum: Properties of Electrons
- Topic: Photons
- Replies: 9
- Views: 351
Re: Photons
If a photon has less energy than the work function, it would not be able to eject electrons.
- Sun Oct 13, 2019 10:18 pm
- Forum: General Science Questions
- Topic: Powerpoint Slides
- Replies: 4
- Views: 270
Re: Powerpoint Slides
No I don't think he does. You can check the different links he has on his website if you're uncertain.
- Sun Oct 13, 2019 10:07 pm
- Forum: Properties of Electrons
- Topic: Photon
- Replies: 5
- Views: 171
Re: Photon
A photon is a particle representing a quantum of light or other electromagnetic radiation. It carries energy proportional to the radiation frequency but has zero rest mass.
- Sun Oct 13, 2019 10:03 pm
- Forum: Significant Figures
- Topic: sig figs and periodic tables
- Replies: 11
- Views: 721
Re: sig figs and periodic tables
Use the periodic table Lavelle put on his website. It's the one that they gave us on the test.
- Sun Oct 06, 2019 12:38 am
- Forum: Molarity, Solutions, Dilutions
- Topic: Which Volume to use for M1
- Replies: 6
- Views: 324
Re: Which Volume to use for M1
it depends on what the question is asking for. Usually you would use the smaller one
- Sun Oct 06, 2019 12:36 am
- Forum: Einstein Equation
- Topic: Planack's constant
- Replies: 8
- Views: 596
Re: Planack's constant
it is used to find E=hv. It can be used with c=lv to calculate and find values
h is planck's constant
h is planck's constant
- Sun Oct 06, 2019 12:32 am
- Forum: Administrative Questions and Class Announcements
- Topic: Test
- Replies: 2
- Views: 105
Re: Test
Yes, my TA told our discussion section that they're modeled after the homework questions. So, only free response.
- Sun Oct 06, 2019 12:18 am
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Naming Compounds
- Replies: 3
- Views: 146
Re: Naming Compounds
in the textbook, there is a page under the fundamentals section that goes over how to name ionic and covalent compounds. Also it has a list of the most common polyatomic ions like chlorate, carbonate, sulfate, nitrate, and etc.
- Sun Oct 06, 2019 12:17 am
- Forum: Empirical & Molecular Formulas
- Topic: Order of elements in formulas
- Replies: 5
- Views: 402
Re: Order of elements in formulas
you start with carbon, then hydrogen and the rest after