Search found 103 matches
- Wed Mar 11, 2020 12:47 am
- Forum: Administrative Questions and Class Announcements
- Topic: ENDGAME Review Session
- Replies: 71
- Views: 5688
Re: ENDGAME Review Session
Thank you for being such an incredible, patient, and dedicated UA. I wouldn't have understood most of the topics we went through in class without your help. Thank you again for spending your free time helping freshmen navigate general chemistry. Good luck with the rest of your adventures!
- Wed Mar 11, 2020 12:41 am
- Forum: Student Social/Study Group
- Topic: Final Exam
- Replies: 22
- Views: 1588
Re: Final Exam
Adriana_4F wrote:Will the final still be worth 180 points now that it is take home and open book?? I really hope so :/
The final will still be 180 points.
- Wed Mar 11, 2020 12:39 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: k' vs kr
- Replies: 13
- Views: 837
Re: k' vs kr
k' is the rate of the reverse reaction.
- Wed Mar 11, 2020 12:38 am
- Forum: Administrative Questions and Class Announcements
- Topic: What is the plan for the final?
- Replies: 16
- Views: 1058
Re: What is the plan for the final?
There is a take home final that is worth 180 points still.
- Wed Mar 11, 2020 12:37 am
- Forum: General Science Questions
- Topic: Dr. Lavelle [ENDORSED]
- Replies: 2
- Views: 366
Re: Dr. Lavelle [ENDORSED]
I love this thread! I want to say thank you to Dr. Lavelle as well for being an incredible professor and for making me realize that I actually really enjoy chemistry. I actually looked forward to studying for the class. I love how dedicated he was to teaching it and how dedicated he was to ensuring ...
- Sat Mar 07, 2020 11:03 am
- Forum: Balancing Redox Reactions
- Topic: Half rxns
- Replies: 27
- Views: 1483
Re: Half rxns
Balancing in acidic solutions means adding H+ and H2O while balancing in basic solutions means balancing with OH- and H2O
- Sat Mar 07, 2020 11:01 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Kelvin or Celsius?
- Replies: 86
- Views: 5722
Re: Kelvin or Celsius?
You use Kelvin since the units of R include Kelvin.
- Sat Mar 07, 2020 11:00 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Inert electrode
- Replies: 9
- Views: 598
Re: Inert electrode
You add a conducting solid such as platinum when there is no conducting in solid in one of the half reactions.
- Sat Mar 07, 2020 10:59 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: temperature and k
- Replies: 5
- Views: 440
Re: temperature and k
If the reaction is endothermic, adding temperature increases K. If the reaction is exothermic, adding temperature reduces K.
- Sat Mar 07, 2020 10:58 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Determining the cathode/anode
- Replies: 9
- Views: 785
Re: Determining the cathode/anode
The more negative cell potential has the most powerful reducing power and is therefore the anode.
- Fri Feb 28, 2020 4:27 pm
- Forum: Balancing Redox Reactions
- Topic: Writing half reactions
- Replies: 9
- Views: 672
Re: Writing half reactions
The oxidized molecules should be on the left and the reduced should be on the right because that is how the equation is set up for cell diagrams.
- Fri Feb 28, 2020 4:27 pm
- Forum: Balancing Redox Reactions
- Topic: How to tell if its being reduced or oxidized
- Replies: 15
- Views: 2142
Re: How to tell if its being reduced or oxidized
Mn goes from +7 to +2 which means it gained electrons and diminishes its positive charge, indicating that it is reduced.
- Fri Feb 28, 2020 4:25 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2
- Replies: 5
- Views: 374
Re: Test 2
Yes, Test 2 covers the second page of Thermodynamics which includes 5G and 5J.
- Fri Feb 28, 2020 4:25 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Spontaneity
- Replies: 12
- Views: 947
Re: Spontaneity
A negative delta G indicates a spontaneous reaction, and a positive delta G indicates a nonspontaneous reaction.
- Fri Feb 28, 2020 4:24 pm
- Forum: Balancing Redox Reactions
- Topic: Test 2
- Replies: 10
- Views: 731
Re: Test 2
Test 2 covers the second page of thermodynamics and the entirety of electrochem.
- Sat Feb 22, 2020 12:09 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: converting T to kelvin
- Replies: 46
- Views: 3531
Re: converting T to kelvin
It is okay to leave the temperature in Celsius or Kelvin when calculating delta T because the number of units that increase or decrease will remain the same no matter what.
- Sat Feb 22, 2020 12:04 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Pt
- Replies: 7
- Views: 480
Re: Pt
Pt stands for platinum and is used as an inert conductor in cell diagrams.
- Sat Feb 22, 2020 12:04 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Midterm 3C
- Replies: 9
- Views: 843
Re: Midterm 3C
NH4Cl can dissociate and donate a proton to the water, lowering the pH.
- Sat Feb 22, 2020 12:03 pm
- Forum: Balancing Redox Reactions
- Topic: Charge of oxygen
- Replies: 15
- Views: 760
Re: Charge of oxygen
Yes, we can assume the oxidation number of oxygen is -2 when it stands alone.
- Sat Feb 22, 2020 12:02 pm
- Forum: Phase Changes & Related Calculations
- Topic: delta G0 versus delta G
- Replies: 15
- Views: 2618
Re: delta G0 versus delta G
Delta G0 is at standard conditions, while delta G is the G value of the reaction at any point in time.
- Sat Feb 15, 2020 5:09 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: degeneracy W
- Replies: 7
- Views: 579
Re: degeneracy W
Na is the number of atoms and it is found using avogadro's number.
- Sat Feb 15, 2020 5:08 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: spontaneity
- Replies: 39
- Views: 1934
Re: spontaneity
Gibbs Free Energy is definitely the best indicator of spontaneity as it takes into account entropy and enthalpy.
- Sat Feb 15, 2020 4:45 pm
- Forum: Balancing Redox Reactions
- Topic: Homework 6K.3 part c
- Replies: 2
- Views: 224
Re: Homework 6K.3 part c
Cl- gains electrons and becomes reduced. As this happens, it oxidizes the H2S, making it lose electrons.
- Sat Feb 15, 2020 4:43 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs Free energy concept
- Replies: 16
- Views: 868
Re: Gibbs Free energy concept
Gibb's free energy is the amount of energy available to do work. It is also the prime indicator of whether a reaction is favorable (spontaneous) or not.
- Sat Feb 15, 2020 4:42 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Midterm Curve
- Replies: 45
- Views: 2269
Re: Midterm Curve
Lavelle doesn't adjust overall grades until the end of the quarter, so no there is no curve for any individulal test.
- Sat Feb 08, 2020 11:52 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Delta H and qp
- Replies: 8
- Views: 204
Re: Delta H and qp
you can assume that when pressure is constant.
- Sat Feb 08, 2020 11:50 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Closed Systems
- Replies: 13
- Views: 718
Re: Closed Systems
a closed system has inflows and outflows of energy and that can be affected by temperature, pressure, and volume.
- Sat Feb 08, 2020 11:50 am
- Forum: Calculating Work of Expansion
- Topic: Units for -PV
- Replies: 5
- Views: 190
Re: Units for -PV
you can use L atm and then convert that to joules. 1 L am is equal to 101.325J
- Sat Feb 08, 2020 11:48 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Endothermic vs Exothermic
- Replies: 10
- Views: 586
Re: Endothermic vs Exothermic
A negative value of q corresponds to an exothermic reaction, and thus a positive value would indicate an endothermic reaction.
- Sat Feb 08, 2020 11:47 am
- Forum: Phase Changes & Related Calculations
- Topic: Enthalpy of a combustion reaction?
- Replies: 7
- Views: 458
Re: Enthalpy of a combustion reaction?
Combustion is an exothermic reaction, so delta H should be negative.
- Fri Jan 31, 2020 2:06 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: state property
- Replies: 8
- Views: 307
Re: state property
A state property is a quantity of a substance that doesn't affect how the substance is made.
- Fri Jan 31, 2020 2:01 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpies of Formation
- Replies: 4
- Views: 194
Re: Enthalpies of Formation
You just need to know that the standard enthalpies of an element in its purest form is zero.
- Fri Jan 31, 2020 1:59 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ideal Gas QUestions
- Replies: 8
- Views: 444
Re: Ideal Gas QUestions
Yes, pressure and volume are inversely related.
- Fri Jan 31, 2020 1:57 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm
- Replies: 8
- Views: 380
Re: Midterm
I think it covers Outlines 1-4.
- Fri Jan 31, 2020 1:56 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: hess's law
- Replies: 13
- Views: 387
Re: hess's law
Yes, they need to be on opposite sides of the reaction to cancel out.
- Thu Jan 23, 2020 7:58 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Chemical equation
- Replies: 5
- Views: 247
Re: Chemical equation
The chemical equations are usually given to you, but you should definitely know equations between acids and their conjugate bases and bases and their conjugate acids.
- Thu Jan 23, 2020 7:56 pm
- Forum: Phase Changes & Related Calculations
- Topic: Autoprotolysis
- Replies: 15
- Views: 822
Re: Autoprotolysis
Autoprotolysis occurs when a proton is transferred between two identical molecules.
- Thu Jan 23, 2020 7:54 pm
- Forum: Ideal Gases
- Topic: Acid and Bases
- Replies: 16
- Views: 579
Re: Acid and Bases
A pH of 7 is neutral. Lower than that is acidic and higher than that is basic.
- Thu Jan 23, 2020 7:52 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K value
- Replies: 7
- Views: 233
Re: K value
you can approximate if k < 10^-3
- Thu Jan 23, 2020 7:51 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: pKa to Kb
- Replies: 12
- Views: 655
Re: pKa to Kb
To find pka from pkb you can do 14-pka and vice versa.
- Fri Jan 17, 2020 8:35 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE and quadratic formula
- Replies: 11
- Views: 593
Re: ICE and quadratic formula
When your K value is smaller than 10^-3, you can ignore the minus x in the denominator and use an approximation to determine molar concentration. you can then make sure an approximation is allowed by seeing if your x is less than 5 percent of K.
- Fri Jan 17, 2020 8:34 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Kw
- Replies: 16
- Views: 453
Re: Kw
Kw is the equilibrium constant for water.
- Fri Jan 17, 2020 8:33 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Solids and Liquids in Le Chatelier
- Replies: 5
- Views: 3261
Re: Solids and Liquids in Le Chatelier
Solids and liquids do not apply to Le Chatelier's principle as they do not affect the equilibrium constant.
- Fri Jan 17, 2020 8:32 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: inert gas added
- Replies: 4
- Views: 157
Re: inert gas added
Adding an inert gas does not have an effect on the equilibrium constant.
- Fri Jan 17, 2020 8:31 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Tips for Test
- Replies: 23
- Views: 1169
Re: Tips for Test
I would definitely do as many of the homework problems as you can, as the TA's make the tests and they model them after the homework problems.
- Wed Jan 08, 2020 4:10 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Re: Q and Ke: Small K value and Large K value
- Replies: 7
- Views: 299
Re: Q and Ke: Small K value and Large K value
Q is the value of products over reactants at any given time in the equation. K is the value of products over reactants when the reaction has reached equilibrium.
- Wed Jan 08, 2020 4:09 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: units
- Replies: 3
- Views: 207
Re: units
The equilibrium constant requires no units.
- Wed Jan 08, 2020 4:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Reverse reaction
- Replies: 6
- Views: 272
Re: Reverse reaction
The reverse reaction begins at the time when q is greater than k and there are more products than reactants.
- Wed Jan 08, 2020 4:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: reactants compared to products
- Replies: 4
- Views: 158
Re: reactants compared to products
In the expression for k, the reactants are in the denominator. So when there is higher pressure of reactants, the equilibrium constant is actually smaller because you are dividing the pressure of the products by a larger number.
- Wed Jan 08, 2020 4:07 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs Kp vs Kc
- Replies: 9
- Views: 382
Re: K vs Kp vs Kc
when writing the expression for k, how do you know when to use brackets or to write p in front?
- Fri Dec 06, 2019 11:14 am
- Forum: Administrative Questions and Class Announcements
- Topic: Chemistry Community Posts
- Replies: 10
- Views: 658
Re: Chemistry Community Posts
I think the TA's will input the points at the very end.
- Fri Dec 06, 2019 11:13 am
- Forum: Bronsted Acids & Bases
- Topic: Lewis vs Bronsted
- Replies: 3
- Views: 307
Re: Lewis vs Bronsted
Lewis acids and bases focus on electron pairs. A Lewis acid is an electron pair acceptor and a Lewis electron pair donor. Bronsted focuses on protons. A bronsted acid is a proton donor and a Bronsted base is a proton acceptor.
- Fri Dec 06, 2019 11:12 am
- Forum: Hybridization
- Topic: hybridization
- Replies: 3
- Views: 256
Re: hybridization
Also, why are there p orbitals that are filled along with the hybridized orbitals?
- Fri Dec 06, 2019 11:12 am
- Forum: Administrative Questions and Class Announcements
- Topic: Final exam
- Replies: 17
- Views: 926
Re: Final exam
How much of the acid-base section is going to be on the final? I'm not sure what to focus on.
- Wed Dec 04, 2019 5:22 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: COORDINATION COMPOUND FINAL REVIEW SESSION
- Replies: 1
- Views: 211
COORDINATION COMPOUND FINAL REVIEW SESSION
Are there going to be any final review sessions on coordination compounds because the one that was meant for coordination compounds ended up only being about intermolecular forces instead?
- Sun Dec 01, 2019 10:33 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Pka vs Ka
- Replies: 10
- Views: 602
Re: Pka vs Ka
pka is the negative log of Ka.
- Sun Dec 01, 2019 10:32 am
- Forum: Air Pollution & Acid Rain
- Topic: Acid Rain
- Replies: 24
- Views: 3946
Re: Acid Rain
Acid rain occurs when compounds like sulfur dioxide and nitrogen oxides are released in the air and react chemically with water, oxygen, and other pollutants in the air.
- Sun Dec 01, 2019 10:31 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Why HF is a weaker acid than HCl
- Replies: 17
- Views: 16308
Re: Why HF is a weaker acid than HCl
The bond between H and Cl is stronger than the one between H and F due to the fact that fluorine is less stable than chlorine and more prone to dissociate.
- Sun Dec 01, 2019 10:29 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Do strong acids dissociate completely in water?
- Replies: 7
- Views: 642
Re: Do strong acids dissociate completely in water?
Strong acids do dissociate completely in water, whereas weak acids do not.
- Sun Dec 01, 2019 10:28 am
- Forum: Conjugate Acids & Bases
- Topic: Conjugate acids
- Replies: 3
- Views: 281
Re: Conjugate acids
The conjugate acid receives the proton, and the conjugate base donates the proton.
- Sun Nov 24, 2019 8:57 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Sigma and Pi Bonds
- Replies: 33
- Views: 1687
Re: Sigma and Pi Bonds
You only need to know that a triple bond contains 1 sigma and 2 pi bonds.
Re: Oxidation
An oxidation number represents the number of electrons lost or gained by an electron in a redox reaction.
- Sun Nov 24, 2019 8:55 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: T-Shape
- Replies: 5
- Views: 437
Re: T-Shape
In the VSEPR model, they are actually significantly far apart because the electrons are trying to get as far apart as possible.
- Sun Nov 24, 2019 8:54 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 2
- Replies: 7
- Views: 285
Re: Test 2
We will probably get them back in discussion this week.
- Sun Nov 24, 2019 8:54 pm
- Forum: Naming
- Topic: Week 9 and Week 10 HW?
- Replies: 21
- Views: 1033
Re: Week 9 and Week 10 HW?
Week 9 and 10 homework will be turned in on Week 10
- Sat Nov 16, 2019 7:04 pm
- Forum: Lewis Structures
- Topic: Bond amount
- Replies: 2
- Views: 131
Re: Bond amount
you want to satisfy the octet rule first, and then check the formal charges on each atoms to see if there needs to be multiple bonds between atoms.
- Sat Nov 16, 2019 7:01 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Melting Points
- Replies: 7
- Views: 481
Re: Melting Points
You simply need to relate bond strength to melting point. For example, a molecule involved in hydrogen bonding would have a higher melting point than one with merely dispersion forces because hydrogen bonds are stronger than London dispersion forces.
- Sat Nov 16, 2019 7:00 pm
- Forum: Dipole Moments
- Topic: Polarity
- Replies: 7
- Views: 467
Re: Polarity
It is the symmetrical shape of carbon tetrachloride that allows its bond polarity to cancel out.
- Sat Nov 16, 2019 6:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 8
- Views: 645
Re: Bond Angles
You just need to memorize the bond angles for the basic molecular shapes without lone pairs, and understand that lone pairs make the angles slightly less than what they are.
- Sat Nov 16, 2019 6:56 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge vs Octet Rule
- Replies: 12
- Views: 770
Re: Formal Charge vs Octet Rule
When drawing Lewis structures you should pay attention to number of electrons, and then the octet rule, and then formal charge in order of increasing importance.
- Sat Nov 16, 2019 6:55 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: strongest intermolecular forces
- Replies: 7
- Views: 758
Re: strongest intermolecular forces
In order of increasing strength it would be dispersion forces, then dipole-dipole, then ion-dipole, and lastly hydrogen bonding (which are 10 percent the strength of covalent bonds)
- Fri Nov 08, 2019 11:42 am
- Forum: Octet Exceptions
- Topic: Lewis Acids and Bases?
- Replies: 11
- Views: 545
Re: Lewis Acids and Bases?
Lewis acids accept pairs of electrons, while Lewis bases donate entire pairs so they form coordinate covalent bonds since the bases are donating an entire pair of electrons.
- Fri Nov 08, 2019 11:41 am
- Forum: Ionic & Covalent Bonds
- Topic: Strength of ionic and covalent bonds
- Replies: 5
- Views: 315
Re: Strength of ionic and covalent bonds
Usually, ionic bonds are stronger because of the higher difference in electronegativity. However, ionic bonds in aqueous solution are actually weaker than covalent bonds because the electronegative regions of the water are attracted to the positive and negative ions in the ionic compound.
- Fri Nov 08, 2019 11:40 am
- Forum: Lewis Structures
- Topic: Exceptions to Octet Rule
- Replies: 7
- Views: 418
Re: Exceptions to Octet Rule
Yes, elements from period 3 and onward have a d shell that can still add on extra electrons.
- Fri Nov 08, 2019 11:39 am
- Forum: Lewis Structures
- Topic: Midterm grades
- Replies: 26
- Views: 1447
Re: Midterm grades
I just went to discussion today and my TA said that they will be given out in discussion next week, or at least by next Wednesday.
- Fri Nov 08, 2019 11:38 am
- Forum: Student Social/Study Group
- Topic: Class Grading
- Replies: 44
- Views: 3744
Re: Class Grading
So for our midterm, we will just get a raw score for now?
- Sat Nov 02, 2019 4:58 pm
- Forum: Properties of Electrons
- Topic: Lewis acids and bases
- Replies: 3
- Views: 272
Lewis acids and bases
I'm a little confused on how Lewis acids and bases form coordinate covalent bonds. Can someone explain this to me?
- Sat Nov 02, 2019 4:57 pm
- Forum: Properties of Electrons
- Topic: Resonance Structures
- Replies: 2
- Views: 243
Resonance Structures
Do resonance structures have to optimum formal charge when we are drawing them? Also, how does one draw a resonance hybrid?
- Sat Nov 02, 2019 4:55 pm
- Forum: Properties of Electrons
- Topic: Spectroscopy
- Replies: 1
- Views: 191
Spectroscopy
What is the difference between molecular spectroscopy and atomic spectroscopy?
- Sat Nov 02, 2019 4:54 pm
- Forum: Properties of Electrons
- Topic: Schrodinger Equation
- Replies: 2
- Views: 281
Schrodinger Equation
I don't really understand the Schrodinger Equation and how it relates to wave function and orbitals. I know we don't need to know how to use it, but can someone explain to me the significance of it?
- Sat Nov 02, 2019 4:53 pm
- Forum: Properties of Electrons
- Topic: Deriving the de Broglie Equation
- Replies: 1
- Views: 247
Deriving the de Broglie Equation
On Outline 2 it says we need to know how to derive the de Broglie equation. Can someone explain to me how to do this?
- Sat Oct 26, 2019 10:36 am
- Forum: Ionic & Covalent Bonds
- Topic: Resonance
- Replies: 7
- Views: 360
Re: Resonance
I didn’t understand why oxygen received a negative charge instead of silver. Can someone please explain this to me? Oxygen gets the negative charge because it has a higher electronegativity than sulfur. If you look at the periodic table, oxygen and sulfur are in the same group but oxygen is above s...
- Sat Oct 26, 2019 10:33 am
- Forum: Ionic & Covalent Bonds
- Topic: octet rule
- Replies: 6
- Views: 269
Re: octet rule
How do you know which elements are able to have an expanded octet?
- Sat Oct 26, 2019 10:33 am
- Forum: Ionic & Covalent Bonds
- Topic: Cation
- Replies: 23
- Views: 1824
Re: Cation
Cations are atoms that lose electrons in order to achieve a full valence shell. They tend to be metals. Anions gain electrons in order to complete their valence shell and tend to be non-metals. Cations lose electrons because they tend to have 3 or less valence electrons in their last shell, and it i...
- Sat Oct 26, 2019 10:29 am
- Forum: Ionic & Covalent Bonds
- Topic: Bond length
- Replies: 11
- Views: 451
Re: Bond length
When a molecule has resonance structures, its bond lengths don't actually look like any one resonance structure. It is actually has an average bond length of all the resonance structures.
- Sat Oct 26, 2019 10:28 am
- Forum: Ionic & Covalent Bonds
- Topic: Identifying Ionic vs Covalent
- Replies: 7
- Views: 295
Re: Identifying Ionic vs Covalent
Covalent bonds form between non-metal atoms as they are more similar in electronegativity, while ionic bonds form between non-metals and metals as they have extremely different levels of electronegativity.
- Sat Oct 19, 2019 2:29 pm
- Forum: Properties of Electrons
- Topic: Wave Function
- Replies: 5
- Views: 241
Re: Wave Function
A wave function is a mathematical equation that tells us the shape of an area in which an electron might be.
- Sat Oct 19, 2019 2:28 pm
- Forum: Properties of Electrons
- Topic: electron
- Replies: 3
- Views: 279
Re: electron
Planck's constant is a significant one you need to remember. The value is 6.262 * 10^-34 J*s.
- Sat Oct 19, 2019 2:23 pm
- Forum: Properties of Electrons
- Topic: Using masses of protons, neutrons, and electrons
- Replies: 7
- Views: 317
Re: Using masses of protons, neutrons, and electrons
Usually, the masses that are required for a calculation are given in the problem or on the formula sheet.
- Sat Oct 19, 2019 2:22 pm
- Forum: Properties of Electrons
- Topic: Momentum
- Replies: 11
- Views: 315
Re: Momentum
Momentum refers to the quantity of motion an object has and is equal to mass times velocity.
- Sat Oct 19, 2019 2:21 pm
- Forum: Properties of Electrons
- Topic: Equations for Test
- Replies: 9
- Views: 371
Re: Equations for Test
You probably need to know the wavelength times frequency = speed of light equation, the E= hv equation, the Schrodinger equation, and the photoelectric effect equation with kinetic energy, the energy absorbed and the work function.
- Sat Oct 19, 2019 2:19 pm
- Forum: Properties of Electrons
- Topic: electron mass
- Replies: 8
- Views: 325
Re: electron mass
Electron mass is usually given in the question or the formula sheet.
- Sun Oct 13, 2019 9:01 am
- Forum: Administrative Questions and Class Announcements
- Topic: KAREN SUN 5-7PM WORKSHOP - DOWNLAOD WORKSHEETS HERE
- Replies: 53
- Views: 5963
Re: KAREN SUN 5-7PM WORKSHOP - DOWNLAOD WORKSHEETS HERE
Is the workshop the "Step-Up" type?
- Sun Oct 13, 2019 8:59 am
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student - Part II [ENDORSED]
- Replies: 298
- Views: 267750
Re: Advice from a Medical Student - Part II [ENDORSED]
As a premed student, I found your story refreshing and inspiring. Sometimes it's hard to remember why I chose the path that I did, but hearing your story made me want to push on and work as hard as I can to reach my goals. Thank you for taking your time to share your experiences and be open about yo...
- Sun Oct 13, 2019 8:56 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg equation [ENDORSED]
- Replies: 73
- Views: 9084
Re: Rydberg equation [ENDORSED]
The Rydberg equation is found in our textbook and is used to calculate the wavelength of any spectral line in many chemical elements. However, Dr. Lavelle taught us a different approach in class because the Rydberg equation does not really show us why everything is solved the way it is.
- Sun Oct 13, 2019 8:53 am
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test 1 [ENDORSED]
- Replies: 107
- Views: 21561
Re: Test 1 [ENDORSED]
According to the syllabus, Test 1 and Test 2 are both worth fifty points each. Although there were 7 questions on Test 1, I'm sure partial credit will be given for each question.
- Sun Oct 13, 2019 8:52 am
- Forum: Administrative Questions and Class Announcements
- Topic: Week 2 Homework Problems [ENDORSED]
- Replies: 67
- Views: 7751
Re: Week 2 Homework Problems [ENDORSED]
For Week 2, I did problems on Fundamentals as a practice for Test 1. But for Week 3, we definitely have to do problems from the Quantum World.
- Sun Oct 13, 2019 8:50 am
- Forum: Limiting Reactant Calculations
- Topic: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
- Replies: 68
- Views: 6999
Re: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
I think that you definitely need to show the mole to mole rations for limiting reactant problems on the tests, as those are the key parts of the problem that Dr. Lavelle wants you to understand.
- Thu Oct 03, 2019 3:13 pm
- Forum: SI Units, Unit Conversions
- Topic: Sig Fig Mistakes
- Replies: 17
- Views: 873
Re: Sig Fig Mistakes
The number of sig figs you use should depend on the number with the least number of sigfigs given in the question. For example, if the problem gives you an amount like 3.2 grams and 4.56 grams, your answer should have 2 sigfigs since 3.2 grams only has 2 sigfigs.
- Thu Oct 03, 2019 3:12 pm
- Forum: SI Units, Unit Conversions
- Topic: Units
- Replies: 5
- Views: 217
Re: Units
In the lecture, Dr. Lavelle says that we won't really be working with Giga, Mega, or Deci very much. I think the main ones are definitely kilo, centi, milli, and pico.