Search found 100 matches
- Sun Mar 15, 2020 11:42 pm
- Forum: Biological Examples
- Topic: iN relation to ATP
- Replies: 3
- Views: 917
Re: iN relation to ATP
For an ATP to be made, you would need an ADP molecule to collide with a Pi molecule. You can see why this is affected by kinetics. In biology, there would be catalysts (enzymes) which speed up the process, but you still need the ADP and Pi to find their way to the enzyme's activation site.
- Sun Mar 15, 2020 11:39 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Activation Energy
- Replies: 4
- Views: 384
Re: Activation Energy
The higher the activation energy, the lower the reaction rate, as a general rule.
- Sun Mar 15, 2020 11:36 pm
- Forum: General Rate Laws
- Topic: Axes labels
- Replies: 6
- Views: 893
Re: Axes labels
The axes label for a first order reaction is ln[A] vs time.
For a second order reaction, 1/[A] vs time.
For a second order reaction, 1/[A] vs time.
- Sun Mar 15, 2020 11:33 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Activation Energy and Energy of a Reaction
- Replies: 10
- Views: 654
Re: Activation Energy and Energy of a Reaction
You can look at arrhenius' equation to see the relationship between reaction rate and temperature.
- Sun Mar 15, 2020 11:31 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Final Review
- Replies: 2
- Views: 368
Re: Final Review
You aren't multiplying rate 1 and 2. You are assuming that Step 2 is the slow step. Using the pre-equilibrium approach, we treat reaction 1 as if it is in equilibrium. Since reaction 1 is in equilibrium, the forward rate is equal to the reverse reaction rate. Using this, we can get rid of the interm...
- Sun Mar 15, 2020 11:15 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: enthalpy constants?
- Replies: 6
- Views: 589
Re: enthalpy constants?
It's for ideal gases, and if they're monatomic, diatomic, and so on. For Chem 14B we are only concerned about monatomic and diatomic ideal gases.
- Sun Mar 15, 2020 11:06 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Doing work vs work done
- Replies: 8
- Views: 700
Re: Doing work vs work done
W for the system is negative when the system does work. W for the system is positive if work is done on the system.
- Sun Mar 15, 2020 11:02 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Difference in volume and temperature
- Replies: 6
- Views: 610
Re: Difference in volume and temperature
It should result in the same value.
- Sun Mar 15, 2020 10:46 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Saying Thank You to Dr. Lavelle
- Replies: 490
- Views: 675598
Re: Saying Thank You to Dr. Lavelle
Thank you Dr. Lavelle for the two quarters of Chem 14A and 14B. You've been a very caring professor and provided many resources for your students. You put in lots of time and energy and we appreciate that!
- Sun Mar 15, 2020 10:37 pm
- Forum: General Rate Laws
- Topic: Rate Constants
- Replies: 3
- Views: 395
Re: Rate Constants
A Pseudo First Order Reaction is reaction which is not first-order reaction naturally but made first order by increasing or decreasing the concentration of one or the other reactant is known as Pseudo first order reaction. Pseudo means 'fake'.
- Sat Mar 14, 2020 8:19 pm
- Forum: Zero Order Reactions
- Topic: Units
- Replies: 9
- Views: 853
Units
What are the units for k in a zero order reaction? What are the units for the reactants of a zero order reaction? I don't understand why the units are what they are can someone help me?
- Sat Mar 14, 2020 8:17 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Steady State
- Replies: 3
- Views: 353
Re: Steady State
But just to be clear, you do not have to worry about steady state approach for Chem 14B
- Sat Mar 14, 2020 8:15 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Steady State
- Replies: 3
- Views: 353
Re: Steady State
The steady state approach is something we don't need to know for this test but is still a very relevant kinetics concept. It is an approach where you measure the rate of the reaction within a very, very small time frame: the moment the reaction starts, you take a quick snapshot of the atoms in react...
- Fri Mar 13, 2020 10:45 pm
- Forum: First Order Reactions
- Topic: 7A.15
- Replies: 1
- Views: 208
7A.15
How do you do 7A.15? How do you find the order each reactant? If they are different orders, don't the units change? Can you still use the given table to solve?
- Fri Mar 13, 2020 10:41 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Order reaction
- Replies: 4
- Views: 423
Re: Order reaction
The order of the reaction can vary depending on the equation and the number of reactants. If you have 3 first order reactants, the order of the reaction is 1+1+1 = 3. If If you have a first order reactant and a second order reactant, the order of the reaction is 1+2 = 3. If you have the rate law, an...
- Fri Mar 13, 2020 10:37 pm
- Forum: First Order Reactions
- Topic: Units
- Replies: 2
- Views: 263
Units
What are the units for first order reactions? Why are they mol*L^-1*s^-1?
What about for second order reactions?
What about for second order reactions?
- Fri Mar 13, 2020 10:34 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Temperature and Kinetics
- Replies: 3
- Views: 282
Temperature and Kinetics
How does the temperature affect the reaction rate? I see that it is in the denominator of the Arrhenius equation but what is it meant to do? Are catalysts affected by temperature?
- Fri Mar 13, 2020 10:33 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Pre Equilibrium Approach
- Replies: 1
- Views: 212
Pre Equilibrium Approach
What is the pre equilibrium approach? How do you use it? What does it mean for kinetics?
- Fri Mar 13, 2020 10:27 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Steady State Approach
- Replies: 1
- Views: 185
Steady State Approach
Can someone explain the concept behind the steady state approach? Why do chemical engineers use lasers?
- Fri Mar 13, 2020 9:32 pm
- Forum: General Rate Laws
- Topic: General Rate Law
- Replies: 2
- Views: 261
General Rate Law
What is a general rate law? What is the equation for a general rate law? Is it k[a]^m*[b]^n...? How do you interpret this?
- Fri Mar 13, 2020 9:31 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6.45
- Replies: 3
- Views: 310
Re: 6.45
Look at the table of experimentally obtained standard reduction tables. Metals that are higher up (more positive) are more likely to be reduced.
- Fri Mar 13, 2020 9:29 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation number
- Replies: 12
- Views: 1258
Re: Oxidation number
Finding an oxidation number is essential to balancing Redox reactions. It will tell you whether an element is being reduced or oxidized. You can find the number by finding the typical oxidation state of the most electronegative nonmetal. There are rules for finding the oxidation state of nonmetals.
- Fri Mar 13, 2020 9:24 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: electrochemical series
- Replies: 4
- Views: 412
Re: electrochemical series
The electrochemical series is just a list of experimentally obtained reaction cell potentials. The more positive the value, the more likely the molecule will be reduced.
- Mon Feb 24, 2020 11:04 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Today in lecture, Dr. Lavelle
- Replies: 4
- Views: 348
Today in lecture, Dr. Lavelle
Today in lecture, Dr. Lavelle played the song Hazey (Stripped) by Glass Animals.
- Sun Feb 16, 2020 10:23 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat Capacity for Calorimeters.
- Replies: 4
- Views: 499
Heat Capacity for Calorimeters.
When you are doing thermodynamic calculations with solutions in calorimeters, why doesn't the mass/mol matter sometimes?
I've seen in some equations you need to use mass/ moles but in others it is ignored. Why is that?
I've seen in some equations you need to use mass/ moles but in others it is ignored. Why is that?
- Sun Feb 16, 2020 10:21 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: 4C.3
- Replies: 2
- Views: 339
Re: 4C.3
For part b, constant volume means that no work is done. Therefore Delta H = q+ nR*Delta T.
- Sun Feb 16, 2020 10:17 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Irreversible isothermal expansion of gas
- Replies: 4
- Views: 286
Re: Irreversible isothermal expansion of gas
If it's isothermal you know Delta T is 0. Volume therefore must change, and the problem will most likely tell you the initial and final volume. Just use the formula Delta S = nRln(V2/V1) to solve for Delta S.
- Sun Feb 16, 2020 10:09 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: Finding the value of W
- Replies: 3
- Views: 374
Re: Finding the value of W
W is equal to 'a', the number of possible ways to achieve a specific energy state, raised to the 'n' power where n is the number of particles in the system.
- Sun Feb 16, 2020 10:07 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Midterm Curve
- Replies: 45
- Views: 2387
Re: Midterm Curve
Dina 2k wrote:how soon does he usually have it graded and back to us?
Dr. Lavelle said in an email that he would have them back for us by Wednesday, 2/19 after lecture.
- Sun Feb 16, 2020 10:06 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: q=n*delta H
- Replies: 5
- Views: 592
Re: q=n*delta H
If Delta H is kJ.mol^-1, then multiplying Delta H by n, mol, would result in an answer in kJ. kJ is the units that work is in, so n*Delta H = q.
- Sun Feb 16, 2020 10:04 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated Systems.
- Replies: 5
- Views: 518
Isolated Systems.
How would you calculate Delta H for an isolated system if q=w=0? Or will it always be 0?
What about for Delta S? If the system doesn't interact with its surroundings, will entropy increase?
What about for W, degeneracy?
What about for Delta S? If the system doesn't interact with its surroundings, will entropy increase?
What about for W, degeneracy?
- Sun Feb 16, 2020 10:01 pm
- Forum: Calculating Work of Expansion
- Topic: Multistep Irreversible Expansion
- Replies: 4
- Views: 425
Multistep Irreversible Expansion
If you had an irreversible expansion that had changes in volume as well as changing temperature, how would you find the overall change in Entropy, given everything you need to calculate for it?
- Sun Feb 16, 2020 9:59 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: S = kblnW explanation
- Replies: 4
- Views: 546
Re: S = kblnW explanation
W is the degeneracy of the system. Entropy is a measure of disorder and thus is related to degeneracy. This equation helps quantify and define this relationship. W is measured by the number of possible states all the molecules in a system could have. If you had 'a' possible configurations and 'n' pa...
- Sun Feb 16, 2020 9:56 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Acids/Bases in non-neutral solutions
- Replies: 2
- Views: 120
Acids/Bases in non-neutral solutions
If you were given the K_A or K_B of an acid/base, and the pH of the solution it was in, how would you find the actual dissociation/ protonation of the acid/base in the solution?
- Sun Feb 16, 2020 9:54 pm
- Forum: Van't Hoff Equation
- Topic: Van't Hoff's Equation
- Replies: 3
- Views: 416
Van't Hoff's Equation
What is the significance of Van't Hoff's Equation?
In lecture Dr. Lavelle mentioned something about how it relates the K, chemical equilibria, to S, entropy, but how is that useful?
In lecture Dr. Lavelle mentioned something about how it relates the K, chemical equilibria, to S, entropy, but how is that useful?
- Sun Feb 16, 2020 9:53 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Types of Delta S
- Replies: 3
- Views: 532
Types of Delta S
What are the different types of Delta S? You have change in entropy resulting from work being done on the system, change in entropy due to temperature change. What else? What is the difference between Delta S_total, Delta S, and Delta S_system and how do you calculate them based on the formulas we'v...
- Sun Feb 16, 2020 9:50 pm
- Forum: Ideal Gases
- Topic: Equation
- Replies: 4
- Views: 447
Re: Equation
I'm assuming you are talking about the Ideal Gas Law, PV=nRT.
P stands for pressure
V stands for volume
n stands for moles
R is a constant that you use to convert your answer into useful units. Based on your units for your other variables you would have a different R value.
T stands for temperature.
P stands for pressure
V stands for volume
n stands for moles
R is a constant that you use to convert your answer into useful units. Based on your units for your other variables you would have a different R value.
T stands for temperature.
- Mon Feb 10, 2020 10:09 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Joules or KJ?
- Replies: 14
- Views: 2899
Re: Joules or KJ?
I'm pretty sure it really doesn't matter whether you leave it Joules or KJ, as long as you convert correctly. I'm assuming if the quantities are given to you in KJ you would leave it as KJ, and the same for Joules, but it doesn't really matter as long as you have the same answer.
- Mon Feb 10, 2020 11:41 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: How do you change the internal energy of an ideal gas?
- Replies: 3
- Views: 196
How do you change the internal energy of an ideal gas?
I'm confused can someone explain to me how the internal energy of an ideal gas changes? Does doing work on the system affect it at all?
- Sun Feb 02, 2020 10:10 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess’ Law
- Replies: 10
- Views: 663
Re: Hess’ Law
Hess's Law states that the total enthalpy is independent of the intermediate reactions. This means you can add up the enthalpy changes of intermediate reactions to find the overall enthalpy change of the reaction. You use it for enthalpy change questions.
- Sat Feb 01, 2020 10:16 pm
- Forum: Phase Changes & Related Calculations
- Topic: Why does steam cause burns?
- Replies: 29
- Views: 1365
Re: Why does steam cause burns?
Steam causes burns because when it comes into contact with your skin, it'll transfer its energy. It has a lot of energy since water requires lots of energy to undergo the phase change from liquid to gas.
- Fri Jan 17, 2020 5:27 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change on Same Side
- Replies: 6
- Views: 252
Re: Change on Same Side
Rita Chen 1B wrote:In something like N2 + 3H2 —> 2NH3, if we increased N2, does it affect H2 as well?
Yes, it would decrease the [H2]. Because you increased the reactants, the forward reaction would be favored. In order for the forward reaction to occur, H2 will be used.
- Fri Jan 17, 2020 5:25 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Product Yield
- Replies: 6
- Views: 201
Re: Product Yield
Dr. Lavelle was talking about Le Chatelier's Principle when he posed these types of questions during lecture. Since the system will try to balance itself and keep itself at low energy, if you remove the product then the forward reaction will be favored. Leftover reactants are not efficient, so in th...
- Fri Jan 17, 2020 5:19 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Changing pH
- Replies: 1
- Views: 188
Changing pH
So in one or two of his lectures, Dr. Lavelle mentioned the pH of water and how adding a small concentration of H+ ions, for example, wouldn't change the pH of the solution since it is significantly smaller than the already present 10^-7 [H+] in water. When are we supposed to use the water pH level ...
- Thu Jan 16, 2020 10:16 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: When to use K and Kp
- Replies: 12
- Views: 454
Re: When to use K and Kp
Maya Pakulski 1D wrote: This might be a dumb question but you calculate all of these the same way right, with products/reactants?
Yes, although you might have to do some other calculations to get everything in the same units.
- Thu Jan 16, 2020 10:11 am
- Forum: Ideal Gases
- Topic: bars vs atm
- Replies: 8
- Views: 307
Re: bars vs atm
It technically doesn't matter, at least for Test 1, the difference between bars and atm. It will result in different answers in different units because you use different R constants, but the answers should be interchangeable with a bit of conversion.
- Mon Jan 13, 2020 11:27 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kw calcuation
- Replies: 5
- Views: 234
Kw calcuation
Why is the activity of water equal to 1 when you are calculating the Kw with [H3O+][OH-]/[H2O]^2?
- Sat Jan 11, 2020 10:27 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: K vs Q
- Replies: 9
- Views: 1808
Re: K vs Q
The Q and K inequality is exactly that: an inequality. K is the ratio of the concentration of products and the concentration of reactants. Q is the exact same equation, [p]/[r]. Given a certain set of physical conditions, the K will always be the same number for a given reaction. This is because K i...
- Sat Jan 11, 2020 10:12 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change in pressure
- Replies: 5
- Views: 280
Re: Change in pressure
The equilibrium will shift to whichever side has less moles. That way, the molecules take up less space and the pressure is minimized. I agree with this but I am not very clear on why this is. Why would balancing the moles result in less pressure? If you had .2 mol of Cl2 and it was undergoing a re...
- Sat Jan 11, 2020 10:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Homework 5I.13
- Replies: 2
- Views: 139
Homework 5I.13
I can't figure out how to get the correct answer for part a) of this problem. Where did the 5.5 x 10^-6 come from?
- Sat Dec 07, 2019 2:14 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Novocaine
- Replies: 1
- Views: 294
Re: Novocaine
H2N group because it can become H3N, which means it is basic (takes H+ away and creates OH-). Just remember that NH3 is amphiprotic.
- Sat Dec 07, 2019 2:10 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: HW 6D11
- Replies: 7
- Views: 673
Re: HW 6D11
How would you know that the coordinator for hydrated Al is 6? Most coordination complexes with first row metals want 6 coordinate covalent bonds with the metal. I think most coordination complexes in general tend to have 6, if they can. It has to do with the shape, octahedral. If Cu^2+ were surroun...
- Sat Dec 07, 2019 2:01 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: J.17
- Replies: 2
- Views: 245
Re: J.17
The bases formed by metals in the first in second groups are strong bases. Therefore, they fully dissociate in water and don't affect pH. Basically, the conjugate acids of strong bases are nonreactive with water.
- Sat Dec 07, 2019 1:57 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: strong acids
- Replies: 1
- Views: 172
Re: strong acids
Because the CH3 methyl group is a destabilizing group that makes the post-reaction anion (conjugate base) less stable.
- Sat Dec 07, 2019 1:39 pm
- Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
- Topic: Stoichiometric Point
- Replies: 2
- Views: 960
Stoichiometric Point
How can a solution with equal acidic and basic properties have a pH unequal to 7? Like we went over in lecture, how come some stoichiometric / equivalence points don't have a neutral pH?
- Tue Dec 03, 2019 11:12 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: TEST 2 POLAR molecule
- Replies: 6
- Views: 459
Re: TEST 2 POLAR molecule
If you were to draw the CCl2H2 as a tetrahedral, you would see that the Chlorines were not opposite of each other, meaning their dipole moments wouldn't cancel. Remember the bond angles that we learned for tetrahedrals.
- Mon Dec 02, 2019 2:49 pm
- Forum: Trends in The Periodic Table
- Topic: Isoelectronic
- Replies: 3
- Views: 407
Re: Isoelectronic
I don't think there can a trend on the periodic table for isoelectronegativity since it's comparing the amount of electrons for different molecules. O^2- is isoelectric with Neon because they both have 10 electrons. In terms of atomic size in an isoelectric series, the more protons there are the sma...
- Mon Dec 02, 2019 2:41 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: How to tell
- Replies: 3
- Views: 316
Re: How to tell
Alison Trinh 1A wrote:To further elaborate, Bronsted acids are considered proton donors. It is a Lewis acid if an electron pair is accepted. A Bronsted base is considered a proton receptor. A Lewis base is considered an electron pair donor.
So do acidic salts contain a bronsted acid or a conjugate acid?
- Mon Dec 02, 2019 2:35 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: seesaw
- Replies: 4
- Views: 274
Re: seesaw
Conceptually, how are Ka and Kb related to Kw? High Ka means strong acid and low Kb means weak base and vice versa, but why do they have to balance out to be equal to Kw?
- Mon Dec 02, 2019 2:28 pm
- Forum: Amphoteric Compounds
- Topic: amphiprotic and amphoteric
- Replies: 9
- Views: 774
Re: amphiprotic and amphoteric
If an atom is said to be amphiprotic then that means that the atom has the ability to donate or accept protons whereas amphoteric is the ability of an atom to act as an acid or base. I'm confused about the difference here between amphiprotic and amphoteric. Bronsted acids are substances that can do...
- Mon Dec 02, 2019 2:16 pm
- Forum: Conjugate Acids & Bases
- Topic: Ligands
- Replies: 12
- Views: 693
Re: Ligands
Kehlin Hayes 4C wrote:Ligands donate electron pairs
So are all ligands Lewis Bases?
- Mon Dec 02, 2019 2:13 pm
- Forum: Lewis Acids & Bases
- Topic: Salts containing conjugate acids/bases
- Replies: 2
- Views: 198
Salts containing conjugate acids/bases
If a salt contains a conjugate acid, how will it react in water? Will it raise the pH and make the solution more basic because the acid takes a hydrogen ion?
- Mon Dec 02, 2019 1:58 pm
- Forum: Conjugate Acids & Bases
- Topic: Conjugate vs Bronsted acids/bases
- Replies: 4
- Views: 277
Re: Conjugate vs Bronsted acids/bases
Bronsted acid: a species that donates a proton Bronsted base: a species that accepts a proton Conjugate base: what is left over after an acid donates a proton Conjugate acid: what is formed when a base accepts a proton Bronsted acids have conjugate bases and Bronsted bases have conjugate acids. In ...
- Mon Dec 02, 2019 1:47 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Bond strength and strength of acid.
- Replies: 6
- Views: 459
Re: Bond strength and strength of acid.
Bond strength helps to determine how easily an acid gives up a hydrogen ion. H-F (strong, short bond) is a weaker acid than H--I (long, weaker bond) because it doesn't give up its hydrogen atom as easily.
- Mon Dec 02, 2019 11:24 am
- Forum: Conjugate Acids & Bases
- Topic: Definition
- Replies: 7
- Views: 504
Re: Definition
Based on the Brønsted–Lowry acid–base theory, a conjugate acid is formed by a base receiving a proton. A conjugate base is the opposite - it is the base formed when the acid donates a proton. So can a molecule become both a conjugate acid and base? If it gains a proton does that make it a conjugate...
- Mon Nov 25, 2019 11:45 pm
- Forum: Bond Lengths & Energies
- Topic: Boiling point
- Replies: 11
- Views: 1232
Re: Boiling point
Higher molar mass means more protons and neutrons. More protons and neutrons means more electrons. More electrons means more movement of electrons. More movement of electrons means a potential for a greater disparity in the distribution of electrons-- a stronger dipole moment. Stronger dipole moment...
- Mon Nov 25, 2019 11:39 pm
- Forum: Dipole Moments
- Topic: Dipole Moment
- Replies: 10
- Views: 897
Re: Dipole Moment
Dipole-Dipole is a describing two molecules, each with an individual dipole, interacting. Thus it is an intermolecular force. A dipole itself is a separation of charge in a molecule, resulting from an uneven distribution of electrons.
- Mon Nov 25, 2019 11:37 pm
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate Covalent Bonds
- Replies: 5
- Views: 1283
Re: Coordinate Covalent Bonds
Coordinate covalent bonds relates to Lewis acids and bases because they can bond to form a coordinate covalent bond. A Lewis acid is missing a full octet since it has an empty orbital and a Lewis base has a free lone pair to share, thus forming a coordinate covalent bond. A metal ion binding to a ch...
- Mon Nov 25, 2019 11:33 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg Equation
- Replies: 4
- Views: 544
Re: Heisenberg Equation
Heisenberg's Indeterminacy principle states that we cannot know the exact velocity and position of an object at any given time, even in theory. This is why we have electron density regions.
- Mon Nov 25, 2019 11:30 pm
- Forum: Trends in The Periodic Table
- Topic: Octet Expansion
- Replies: 5
- Views: 482
Re: Octet Expansion
Octet expansion only occurs when a period 3 element utilizes a d orbital.
- Mon Nov 25, 2019 11:28 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Ground state? [ENDORSED]
- Replies: 8
- Views: 1994
Re: Ground state? [ENDORSED]
Ground state means that none of the electrons are excited. They included that in the test to make sure there was no misunderstanding about how to write the electron configuration of the atoms they listed. All the electrons are in their lowest energy state.
- Sun Nov 10, 2019 10:45 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Length Trends
- Replies: 4
- Views: 441
Re: Bond Length Trends
I think the size of the atom also matters, as do lone pairs and electronegativity.
- Sun Nov 10, 2019 10:43 pm
- Forum: Bond Lengths & Energies
- Topic: negative Ep
- Replies: 5
- Views: 410
Re: negative Ep
Is Ep the measure of the strength of the bond or how much energy it takes to break the bond or are they the same thing?
- Sun Nov 10, 2019 10:41 pm
- Forum: Bond Lengths & Energies
- Topic: test 2
- Replies: 16
- Views: 943
Re: test 2
Will test 2 contain problems verbatim from the homework like the midterm did?
- Sun Nov 10, 2019 10:40 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge and Resonance
- Replies: 5
- Views: 466
Formal Charge and Resonance
Do formal charges give any information on the resonance of a molecule?
- Sun Nov 10, 2019 10:38 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation Number
- Replies: 6
- Views: 446
Re: Oxidation Number
So does this mean that the oxidation number is basically the sum of the formal charges of all atoms within a molecule?
- Sun Nov 10, 2019 10:37 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Partial Charge
- Replies: 2
- Views: 217
Re: Partial Charge
Formal charge is what you calculate with your FC= V - (LP + B/2) formula and it helps you understand the distribution of charge when making bonds by showing the gain or loss of electrons for that atom. Partial charge is talking more about electron distribution in the molecule as a whole, generally a...
- Sun Nov 10, 2019 10:34 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: central atom
- Replies: 21
- Views: 1079
Re: central atom
What do you do for exceptions? Such as in an atom consisting of N and O, which would be the central atom? O technically has the lower ionization energy than N. Does the number of desired bonds matter when considering the central atom more than the electronegativity?
- Sun Nov 10, 2019 10:32 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Calculating formal charge
- Replies: 4
- Views: 286
Re: Calculating formal charge
When calculating formal charge, you would count each e- in lone pairs as individual e- but shared e- as a whole because their charge is not solely distributed to one atom.
- Sun Nov 10, 2019 10:30 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation Number
- Replies: 6
- Views: 446
Oxidation Number
What is an oxidation number and how is it calculated? Is it just the charge of the molecule as an anion?
- Sun Nov 10, 2019 10:29 pm
- Forum: Dipole Moments
- Topic: Dipole v Instantaneous Dipole
- Replies: 3
- Views: 359
Re: Dipole v Instantaneous Dipole
A dipole moment is what is caused by a difference in electronegativity. Thus, unless it is a bond between two identical atoms, a dipole moment will exist. Dipole moments are defined as an unequal sharing of electrons, which results in slight differences in charge within the molecule. An instantaneou...
- Sun Nov 03, 2019 10:07 pm
- Forum: Dipole Moments
- Topic: Dipole moment calculation
- Replies: 2
- Views: 216
Re: Dipole moment calculation
I think in Chemistry it's pointing toward the δ- but in physics it points toward the δ+.
- Sun Nov 03, 2019 10:06 pm
- Forum: Resonance Structures
- Topic: Showing resonance
- Replies: 8
- Views: 405
Re: Showing resonance
What about drawing like curves and circles? I've seen those on the internet.
- Sun Nov 03, 2019 10:05 pm
- Forum: Ionic & Covalent Bonds
- Topic: Question about bonds
- Replies: 2
- Views: 254
Question about bonds
Can someone explain metals a bit? About the bonds they form and their lowest energy state. Especially those in the lower rows of the periodic table I don't really understand.
- Sun Nov 03, 2019 9:59 pm
- Forum: Photoelectric Effect
- Topic: Dino Nuggets Review #8.a)
- Replies: 2
- Views: 198
Dino Nuggets Review #8.a)
What did you all put as your response to #8 part a on the Midterm Review?
Q: Write an equation using words only that captures the conservation of energy in the photoelectric effect. Describe the conceptual change that arose from the photoelectric experiment and discuss how intensity plays a role.
Q: Write an equation using words only that captures the conservation of energy in the photoelectric effect. Describe the conceptual change that arose from the photoelectric experiment and discuss how intensity plays a role.
- Wed Oct 30, 2019 9:59 am
- Forum: Administrative Questions and Class Announcements
- Topic: DINO NUGGETS Review Session! Download Problems HERE [ENDORSED]
- Replies: 52
- Views: 6964
Re: DINO NUGGETS Review Session! Download Problems HERE [ENDORSED]
Where can I find the review problems? Also, how do I download the problems?
Chem Mod: Please simply scroll up and read the post! Everything you've asked is there.
Chem Mod: Please simply scroll up and read the post! Everything you've asked is there.
- Sun Oct 20, 2019 10:58 pm
- Forum: *Shrodinger Equation
- Topic: Shrodinger Equation
- Replies: 3
- Views: 180
Re: Shrodinger Equation
Will we need to know how to use Shrodinger's Equation on the test or just understand it conceptually, like what an allowed energy level and a not allowed energy level looks like?
- Sun Oct 20, 2019 10:56 pm
- Forum: *Shrodinger Equation
- Topic: Z^2 in Schrodinger Equation
- Replies: 2
- Views: 647
Re: Z^2 in Schrodinger Equation
Z is the measure of the number of protons right? The radius of a helium atom is smaller than that of a hydrogen atom because there is a greater positive charge pulling the electrons tighter. Maybe that's what the book is trying to get at?
- Sun Oct 20, 2019 10:53 pm
- Forum: *Shrodinger Equation
- Topic: Schrodinger for exam
- Replies: 20
- Views: 935
Re: Schrodinger for exam
So what exactly is the relationship between Schrodinger's Equation, wave functions, and orbitals?
- Sun Oct 13, 2019 11:29 pm
- Forum: Significant Figures
- Topic: sig figs and periodic tables
- Replies: 11
- Views: 738
Re: sig figs and periodic tables
If you rounded your sig figs/ used a different periodic table and showed that through your work on a problem that you got incorrect because of rounding would you lose points?
- Sun Oct 13, 2019 11:27 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Test 1 Grading
- Replies: 12
- Views: 995
Re: Test 1 Grading
Is there a specific way that we should be showing our work to maximize partial credit like showing unit conversions and stuff? Also, since Dr. Lavelle didn't explicitly go over Sig Figs how impactful are they going to be on the test grading?
- Sun Oct 13, 2019 11:22 pm
- Forum: Electronegativity
- Topic: Electronegativity
- Replies: 4
- Views: 1090
Re: Electronegativity
Electronegativity is affected by the amount of valence electrons and the amount of orbitals. The more orbitals there are, the farther the electrons are from the positive nucleus. And since elements want to exist in their ideal state, they want to get as close as the a filled outer shell. That means ...
- Sun Oct 13, 2019 11:17 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic vs Covalent
- Replies: 32
- Views: 43916
Re: Ionic vs Covalent
Ionic bonds are stronger than covalent bonds. However, in water, ionic bonds are weaker. This is why you might hear that covalent bonds are stronger in your biology classes.
- Sun Oct 13, 2019 11:04 pm
- Forum: Properties of Light
- Topic: Changing Amplitude
- Replies: 2
- Views: 198
Re: Changing Amplitude
Increasing the amplitude will increase the intensity, but it does not affect the number of protons.
- Sun Oct 13, 2019 1:52 pm
- Forum: Properties of Light
- Topic: wavelike properties
- Replies: 4
- Views: 277
Re: wavelike properties
Wavelike properties is talking about things like amplitude, frequency, and wavelength. Only particles with small enough mass will exhibit wavelike properties, which can be proven by DeBroglie's equation. Things with wavelengths less than 10^-15m are widely considered to not exhibit wavelike properti...
- Fri Oct 04, 2019 10:01 pm
- Forum: General Science Questions
- Topic: Kelvin
- Replies: 3
- Views: 193
Re: Kelvin
It means super-duper cold. 0 Kelvin, or absolute zero, is a temperature that we can never actually reach (limit).
- Fri Oct 04, 2019 9:55 pm
- Forum: Limiting Reactant Calculations
- Topic: Determining Limiting Reactants
- Replies: 2
- Views: 159
Re: Determining Limiting Reactants
I think generally converting moles to grams before you have determined the limiting reactant makes the equation a little more complicated and leaves more room for error. Maybe in an equation where you can't determine the moles for every singe element, using grams would be the easiest method. E.g. if...
- Fri Oct 04, 2019 9:47 pm
- Forum: Limiting Reactant Calculations
- Topic: Study Strategies/Youtube Videos
- Replies: 14
- Views: 614
Re: Study Strategies/Youtube Videos
Aside from YouTube channels and videos on that platform, Bruincast is also very valuable resource. If you learn best through video, maybe watching some lectures from our UCLA professors will be a good way to review.
- Fri Oct 04, 2019 9:39 pm
- Forum: Properties of Electrons
- Topic: Expectations
- Replies: 4
- Views: 324
Re: Expectations
For test 1, I've been told that as long as you do the homework, go to class, and attend discussion, you will succeed :) But as far as I know, no homework questions will be there verbatim on test 1. You won't be tested on the stuff we learned in lecture today about Quantum Mechanics and light. Don't ...
- Fri Oct 04, 2019 9:34 pm
- Forum: Properties of Light
- Topic: Electromagnetic vectors
- Replies: 1
- Views: 103
Re: Electromagnetic vectors
The vectors are just there to indicate the direction and intensity of the fields as they travel. I think the answer to the second part of this question is probably a lot more complicated than what we would be learning in class. From what I've seen (very little), the magnetic field and electric field...