Search found 60 matches
- Sun Mar 10, 2019 12:50 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Study Advice
- Replies: 73
- Views: 6737
Re: Study Advice
Lyndon and Karen's workshops are usually the most helpful for me.
- Sun Mar 10, 2019 12:47 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Bimolecular
- Replies: 13
- Views: 2171
Re: Bimolecular
A bimolecular reaction involves two reactants. This is an example of a second-order reaction.
- Sun Mar 10, 2019 12:44 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: k & K
- Replies: 18
- Views: 2123
Re: k & K
The difference is that k is Boltzmann's constant, while K is the equilibrium constant for a given reaction.
- Sun Mar 03, 2019 3:17 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: H+, OH-, water
- Replies: 9
- Views: 869
Re: H+, OH-, water
You would include H+ and OH-, but not H2O
- Sun Mar 03, 2019 3:13 pm
- Forum: Balancing Redox Reactions
- Topic: oxidizing agent and reducing agent
- Replies: 15
- Views: 1306
Re: oxidizing agent and reducing agent
The compound that is reduced is considered the oxidizing agent. The compound that is oxidized is the reducing agent.
- Sun Mar 03, 2019 3:12 pm
- Forum: Balancing Redox Reactions
- Topic: Creating a cell diagram
- Replies: 8
- Views: 726
Re: Creating a cell diagram
You would include H+ but not H2O
- Sat Feb 23, 2019 5:00 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: delta S= q(rev)/ T
- Replies: 5
- Views: 2130
Re: delta S= q(rev)/ T
This equation is used to find the change in entropy for isothermal reversible reactions.
- Sat Feb 23, 2019 4:51 am
- Forum: Balancing Redox Reactions
- Topic: difference between oxidation and reduction
- Replies: 8
- Views: 913
Re: difference between oxidation and reduction
When the charge changes from +2 to +4, that means the atom has lost 2 electrons. Since there is a loss of electrons, this is an example of an oxidation reaction.
- Sat Feb 23, 2019 4:49 am
- Forum: Balancing Redox Reactions
- Topic: Galcanic cell
- Replies: 3
- Views: 368
Re: Galcanic cell
Galvanic cell is just another name for a voltaic cell.
- Tue Feb 19, 2019 1:40 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Microstates
- Replies: 7
- Views: 1021
Re: Microstates
The equation to find entropy is S=kblnW, where W=(# of microstates)^(# of molecules)
- Tue Feb 19, 2019 1:36 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Cup of Tea
- Replies: 17
- Views: 2430
Re: Cup of Tea
It can exchange both matter and energy with its surroundings.
- Tue Feb 19, 2019 1:33 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Extensive vs Intensive
- Replies: 7
- Views: 1208
Re: Extensive vs Intensive
Extensive properties depend on the amount of matter being measured. On the other hand, intensive properties do not depend on the amount of substance present.
- Sat Feb 09, 2019 8:55 pm
- Forum: Calculating Work of Expansion
- Topic: Work
- Replies: 5
- Views: 447
Re: Work
Danny Elias Dis 1E wrote:Is this situation also the case where deltaU = q?
Yes, because ΔU = q+w, and if w = 0, then ΔU = q+0 = q.
- Sat Feb 09, 2019 8:51 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: U
- Replies: 7
- Views: 604
Re: U
This mean that internal energy depends only on the current state of the system and is independent of how that state was prepared. Other examples of state functions are pressure, volume, temperature, and density.
- Sat Feb 09, 2019 8:39 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: q= -w
- Replies: 8
- Views: 676
Re: q= -w
This is the case when the change in internal energy is 0
- Wed Jan 30, 2019 10:57 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: increasing pressure, what happens to concentration?
- Replies: 10
- Views: 2416
Re: increasing pressure, what happens to concentration?
Increasing pressure will cause the reaction to proceed towards the side with less moles of gas.
- Wed Jan 30, 2019 10:49 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: closed vs isolated
- Replies: 14
- Views: 996
Re: closed vs isolated
A closed system has a fixed amount of matter, but can exchange energy with its surroundings. An isolated system there cannot be transfer of energy or matter between a system and its surroundings. An open system can freely exchange matter and energy with its surroundings.
- Wed Jan 30, 2019 10:37 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: ICE
- Replies: 19
- Views: 1424
Re: ICE
E stands for equilibrium concentration.
- Wed Jan 30, 2019 10:36 pm
- Forum: Ideal Gases
- Topic: pH and pOH
- Replies: 18
- Views: 1840
Re: pH and pOH
The question will tell you which to solve for.
- Wed Jan 30, 2019 10:29 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q VS. K
- Replies: 13
- Views: 1594
Re: Q VS. K
Q and K are calculated the same way. If Q<K, then the reaction will tend to proceed towards the products. If Q>K, then the reaction will proceed towards the reactants.
- Thu Jan 24, 2019 11:59 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Neutral solutions
- Replies: 2
- Views: 246
Re: Neutral solutions
I think the solution is considered neutral if [H3O+] is equal to 10^-7. If it is less than that, then it is considered a basic solution.
- Sun Jan 20, 2019 10:57 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction Quotient
- Replies: 10
- Views: 944
Re: Reaction Quotient
By comparing Q to K, it will tell you whether the reaction will proceed forward, backward, or is already at equilibrium If Q = K, then the reaction is at equilibrium If Q < K, then the reaction will favor the products (proceeds forward) If Q > K, then the reaction will favor the reactants (proceeds ...
- Sun Jan 20, 2019 10:50 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Reaction Quotient
- Replies: 3
- Views: 530
Re: Reaction Quotient
The reaction quotient, Q, tells you the ratio of products to reactants at any given instant. The equilibrium constant, K, gives you the ratio of products to reactants when the reaction is at equilibrium.
- Sun Jan 20, 2019 10:43 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Solids and Liquids with the Reaction Quotient
- Replies: 3
- Views: 393
Re: Solids and Liquids with the Reaction Quotient
No, solids and liquids are not included in Q or K.
- Thu Jan 10, 2019 10:49 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Effects on Equilibrium
- Replies: 2
- Views: 213
Re: Effects on Equilibrium
It's important to note that different initial concentrations of a reaction does not affect the equilibrium constant.
- Thu Jan 10, 2019 10:35 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Calculating K
- Replies: 3
- Views: 146
Re: Calculating K
We can use either partial pressure or concentration to calculate K, but partial pressure can only be used in gas phase reactions.
- Thu Jan 10, 2019 10:32 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Writing Equilibrium Expressions
- Replies: 3
- Views: 189
Re: Writing Equilibrium Expressions
Yes, brackets are used specifically in equilibrium expressions to indicate the concentration of a certain substance.
- Sun Dec 09, 2018 4:17 pm
- Forum: Limiting Reactant Calculations
- Topic: moles of reagant
- Replies: 4
- Views: 694
Re: moles of reagant
You would have to convert the amount of grams of the limiting reactant to moles, then compare the ratios of the reactants in the balanced equation to figure out how many moles of the reactant are required.
- Sun Dec 09, 2018 4:13 pm
- Forum: Amphoteric Compounds
- Topic: Examples
- Replies: 5
- Views: 770
Examples
What are some examples of amphoteric compounds?
- Sat Dec 08, 2018 5:11 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: pH formula?
- Replies: 69
- Views: 3552
Re: pH formula?
The pH formula is pH = -log[H+]. I don't think we need to know how it is derived.
- Sat Dec 08, 2018 4:57 pm
- Forum: Naming
- Topic: Do we have to memorize some of the ligand names?
- Replies: 3
- Views: 310
Re: Do we have to memorize some of the ligand names?
I think we need to memorize the charges of the ligands as well.
- Sat Dec 08, 2018 4:55 pm
- Forum: Administrative Questions and Class Announcements
- Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
- Replies: 118
- Views: 20747
Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Thank you so much for the final review and practice problems!
- Fri Nov 30, 2018 4:18 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Acid vs base [ENDORSED]
- Replies: 15
- Views: 1467
Re: Acid vs base [ENDORSED]
A Lewis acid is an electron acceptor and a Lewis base is an electron donor.
- Fri Nov 30, 2018 4:16 pm
- Forum: Lewis Acids & Bases
- Topic: Bronsted Acids & Bases vs. Lewis Acid & Bases
- Replies: 3
- Views: 286
Re: Bronsted Acids & Bases vs. Lewis Acid & Bases
A Lewis acid is an electron acceptor, and a Lewis base is an electron donor. On the other hand, a Bronsted acid is a proton donor, and a Bronsted base is a proton acceptor. The definition that you use just depends on whether you're focusing on the transfer of electrons or protons.
- Fri Nov 30, 2018 4:12 pm
- Forum: Amphoteric Compounds
- Topic: Amphoteric Oxides
- Replies: 4
- Views: 727
Re: Amphoteric Oxides
I don't know if we'll have to remember all of them, but Dr. Lavelle said that there is a diagonal band of amphoteric oxides, between the metal oxides and nonmetal oxides, that closely matches the diagonal band of metalloids.
- Sun Nov 25, 2018 3:00 am
- Forum: Dipole Moments
- Topic: Dipole Moment
- Replies: 2
- Views: 607
Re: Dipole Moment
Greater polarity between molecules leads to a stronger dipole moment. This means that the larger the difference in electronegativity of the bonded atoms, the larger the dipole moment.
- Sun Nov 25, 2018 2:56 am
- Forum: Sigma & Pi Bonds
- Topic: Double Bonds
- Replies: 9
- Views: 1001
Re: Double Bonds
Yes. With multiple bonds, there is only one sigma-bond and each additional bond is a pi-bond. For a double bond there is one sigma-bond and one pi-bond.
- Sun Nov 25, 2018 2:46 am
- Forum: Sigma & Pi Bonds
- Topic: Which bond would break first.
- Replies: 15
- Views: 2601
Re: Which bond would break first.
The pi-bond would break first since pi-bonds are weaker than sigma-bonds. This is because the side-by-side overlap in a pi-bond is smaller and weaker than the end-to-end overlap in a sigma bond.
- Sun Nov 25, 2018 2:43 am
- Forum: Sigma & Pi Bonds
- Topic: Sigma and pi bonds and hybridization
- Replies: 2
- Views: 515
Sigma and pi bonds and hybridization
What is the relationship between sigma/pi bonds and hybridization?
- Sun Nov 18, 2018 7:52 pm
- Forum: Dipole Moments
- Topic: Difference between dipole and london forces?
- Replies: 5
- Views: 499
Re: Difference between dipole and london forces?
Dipole-dipole forces occur between polar molecules when the positive end of one is attracted to the negative end of the other and vice-versa.
London forces occur between all types of molecules (polar and non-polar) and are weaker than dipole-dipole forces.
London forces occur between all types of molecules (polar and non-polar) and are weaker than dipole-dipole forces.
- Sun Nov 18, 2018 7:48 pm
- Forum: Sigma & Pi Bonds
- Topic: usage of sigma/pi
- Replies: 6
- Views: 666
Re: usage of sigma/pi
RoopshaChatterjee 1G wrote:Can the sigma/pi bonds also be used to determine the structure of the molecule?
Sigma and pi bonds can't be used to determine the structure of a molecule since they do not affect shape or structure.
- Sun Nov 18, 2018 7:43 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs
- Replies: 3
- Views: 347
Lone Pairs
When there is a lone pair, why does this make the bond angle smaller? Also, how do you determine how much smaller the bond angle will be?
- Thu Nov 08, 2018 11:24 am
- Forum: Bond Lengths & Energies
- Topic: MIDTERM Bond Length Question
- Replies: 15
- Views: 1523
Re: MIDTERM Bond Length Question
Since a resonance hybrid is a blend of Lewis structures, all the bond lengths are the same. Thus, even though there are both single and double bonds in the resonance structure, all of the bond lengths will be the average between the different bond lengths of the structure. For this specific question...
- Thu Nov 08, 2018 11:12 am
- Forum: Resonance Structures
- Topic: Resonance Structures
- Replies: 3
- Views: 354
Resonance Structures
How can you determine if a certain compound requires a resonance structure?
- Tue Nov 06, 2018 1:04 pm
- Forum: Ionic & Covalent Bonds
- Topic: Greater Ionic Character? [ENDORSED]
- Replies: 3
- Views: 586
Re: Greater Ionic Character? [ENDORSED]
You can determine this by looking at the difference in the electronegativity of the atoms involved in the bond. The bond with a greater difference in electronegativity has a greater ionic character.
- Sat Nov 03, 2018 11:46 pm
- Forum: Octet Exceptions
- Topic: Copper
- Replies: 10
- Views: 940
Copper
Why is the ground state electron configuration of copper [Ar]3d^(10)4s^(1) and not [Ar]3d^(9)4s^(2)?
- Sat Nov 03, 2018 11:42 pm
- Forum: Resonance Structures
- Topic: Resonance [ENDORSED]
- Replies: 2
- Views: 233
Resonance [ENDORSED]
How does resonance help to stabilize the molecule?
- Sat Nov 03, 2018 11:40 pm
- Forum: Ionic & Covalent Bonds
- Topic: Homework Problem 3.19
- Replies: 2
- Views: 282
Homework Problem 3.19
Give the ground-state electron configuration and number of unpaired electrons expected for each of the following ions:
(a) Sb3
(b) Sn4
How do you find the number of unpaired electrons?
(a) Sb3
(b) Sn4
How do you find the number of unpaired electrons?
- Sun Oct 28, 2018 12:38 am
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy and Electron Affinity
- Replies: 9
- Views: 1805
Re: Ionization Energy and Electron Affinity
Why are electrons that are further away from the nucleus easier to remove? The nucleus has a positive charge, which attracts negatively charged electrons. If electrons are farther away from the nucleus, this positive nuclear charge is weaker, so the electrons aren't pulled as tightly towards the nu...
- Wed Oct 24, 2018 10:50 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Subshells/Orbitals
- Replies: 5
- Views: 510
Re: Subshells/Orbitals
I don't think we need to know the specific shapes of the f orbitals, we just need to know that it has 7 different orbitals which hold a total of 14 electrons.
- Wed Oct 24, 2018 10:44 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Electron Configuration Order
- Replies: 2
- Views: 119
Re: Electron Configuration Order
This is because the 4s orbital is slightly closer to the nucleus, and thus has a slightly lower energy than the 3d orbital. This means that the 4s orbital will be filled before the 3d orbital. This concept applies to the elements Calcium (Ca) and Potassium (K).
- Thu Oct 18, 2018 2:28 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodes/ Nodals
- Replies: 2
- Views: 224
Re: Nodes/ Nodals
A node is where the probability of finding an electron is zero.
- Thu Oct 18, 2018 2:26 pm
- Forum: *Shrodinger Equation
- Topic: Schrodinger Equation
- Replies: 2
- Views: 92
Schrodinger Equation
I know we do not have to know how to use the Schrodinger Equation in calculations, but what specifically do we need to know about the equation?
- Tue Oct 16, 2018 11:13 am
- Forum: Photoelectric Effect
- Topic: Spectroscopic series
- Replies: 2
- Views: 554
Re: Spectroscopic series
I agree with Emily, I think the Balmer series and the Lyman series are the two that we need to know. The Balmer series corresponds with the visible region of the spectrum, and electrons come to rest at energy level n=2. The Lyman series corresponds with the ultraviolet region, and electrons come to ...
- Fri Oct 12, 2018 2:16 pm
- Forum: DeBroglie Equation
- Topic: Measurable wavelengths
- Replies: 3
- Views: 171
Re: Measurable wavelengths
In the 12-1 lecture Dr. Lavelle also said wavelike properties are measurable when the De Brogile wavelength is at least (some value)x10^-18.
- Fri Oct 12, 2018 2:11 pm
- Forum: Properties of Electrons
- Topic: Energy emitted by electrons
- Replies: 6
- Views: 515
Re: Energy emitted by electrons
The energy that was lost is released as electromagnetic radiation, which is why the change in energy is negative.
- Fri Oct 12, 2018 2:05 pm
- Forum: DeBroglie Equation
- Topic: Question about diffraction patterns
- Replies: 2
- Views: 413
Re: Question about diffraction patterns
Constructive interference is when two waves meet in a way that their crests line up. This results in a wave of a higher amplitude. On the other hand, destructive interference is when the crest of one wave meets with the trough of the other. This results in a wave of lower amplitude.
- Thu Oct 04, 2018 4:15 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Molar Masses
- Replies: 9
- Views: 545
Re: Molar Masses
I remember Dr. Lavelle saying that we will be given a periodic table for the test, and we can use that to calculate the molar mass of the elements and compounds.
- Wed Oct 03, 2018 5:23 pm
- Forum: Significant Figures
- Topic: Significant Figures
- Replies: 3
- Views: 224
Significant Figures
When should we apply the rules of significant figures? Do we use them throughout the problem or just for the final answer?
- Tue Oct 02, 2018 3:19 pm
- Forum: Balancing Chemical Reactions
- Topic: Net number of molecules
- Replies: 3
- Views: 487
Net number of molecules
How do you calculate the net number of moles produced in a balanced chemical reaction?