## Search found 61 matches

Sun Mar 17, 2019 8:12 pm
Forum: Balancing Redox Reactions
Topic: Triprotic
Replies: 7
Views: 2950

### Re: Triprotic

yes it's H3PO4 with 3 protons
Sun Mar 17, 2019 8:07 pm
Forum: *Enzyme Kinetics
Topic: How do you tell if something is a catalyst vs an intermediate?
Replies: 16
Views: 806

### Re: How do you tell if something is a catalyst vs an intermediate?

intermediates are consumed by the reaction, meaning they do not show up in the final rate law.
catalysts are regenerated at the end, and they do show up in the rate law.
Sun Mar 17, 2019 8:04 pm
Forum: Balancing Redox Reactions
Topic: Oxidizing powers
Replies: 2
Views: 234

### Re: Oxidizing powers

the more positive reduction potential the higher the oxidizing power.
Sat Mar 16, 2019 11:34 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: How to know which conducting element to add?
Replies: 3
Views: 242

### Re: How to know which conducting element to add?

I think for this test, using Pt is the safest bet
Sat Mar 16, 2019 11:29 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Elementary Rxns
Replies: 2
Views: 285

### Re: Elementary Rxns

Rate = k[A]^2[B]^2. You can use the coefficients as long as the reaction is an elementary reaction
Sat Mar 09, 2019 7:36 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: reaction rate
Replies: 2
Views: 86

### Re: reaction rate

because the faster rate is dependent on the slower one.
Sat Mar 09, 2019 7:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Negligible X
Replies: 3
Views: 95

### Re: Negligible X

The 5% rule, so if your equilibrium value is smaller than 10^-3, you can ignore that x to make your calculation easier.
Fri Mar 08, 2019 8:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp
Replies: 7
Views: 206

### Re: Kp

I'd say use either one it's fine, just make sure all are the units are the same in a problem just to avoid any calculation mistakes.
Fri Mar 08, 2019 7:24 pm
Forum: *Enzyme Kinetics
Topic: Enzymes
Replies: 8
Views: 737

### Re: Enzymes

Enzymes lower the activation energy.
Fri Mar 08, 2019 7:18 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Test 2: Melting Ice
Replies: 6
Views: 385

### Re: Test 2: Melting Ice

I was confused about this as well. Sun is melting the ice, so it the ice has to be absorbing heat?
someone help, thanks
Fri Mar 08, 2019 7:09 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Pt
Replies: 14
Views: 352

### Re: Pt

Pt is added when no conducting solids are present.
Tue Feb 19, 2019 1:20 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterms
Replies: 4
Views: 167

### Re: Midterms

My TA said tomorrow after lecture, so just stay for the lookout afterwards.
Tue Feb 19, 2019 1:19 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Concentration and free energy
Replies: 2
Views: 90

### Re: Concentration and free energy

Yes! it's products and reactants concentrations that affect the free energy.
Tue Feb 19, 2019 12:54 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Negative Delta G
Replies: 7
Views: 492

### Re: Negative Delta G

This graph will help better visualize the concept!
Tue Feb 19, 2019 12:52 am
Forum: Administrative Questions and Class Announcements
Topic: 14BL and 14C
Replies: 5
Views: 343

### Re: 14BL and 14C

I heard that it's not too bad, just busy work. It depends on what type of person you are!
Tue Feb 19, 2019 12:49 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: entropy and enthalpy
Replies: 5
Views: 152

### Re: entropy and enthalpy

Yes they are, and it's depending on whether the reaction is exothermic or endothermic.
Thu Feb 07, 2019 12:04 pm
Forum: Calculating Work of Expansion
Topic: Ideal gas expansion
Replies: 4
Views: 111

### Re: Ideal gas expansion

Maybe because the work energy itself is still an amount, disregarding the fact that it's lost or gained. But I'm not sure though, can someone explain?
Thu Feb 07, 2019 11:54 am
Forum: Ideal Gases
Topic: Ideal gas constant R
Replies: 10
Views: 533

### Re: Ideal gas constant R

Depends on the units! L or J
Thu Feb 07, 2019 11:24 am
Forum: Administrative Questions and Class Announcements
Topic: Week 5 Homework
Replies: 3
Views: 139

### Re: Week 5 Homework

Yes! Anything works because it counts as practice for the midterm.
Thu Feb 07, 2019 11:10 am
Forum: Phase Changes & Related Calculations
Topic: Solids and Liquids
Replies: 5
Views: 120

### Re: Solids and Liquids

Solids and liquids don't count because their pressure and volume aren't affected
Sat Feb 02, 2019 6:54 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Open, closed, or isolated systems
Replies: 10
Views: 1949

### Re: Open, closed, or isolated systems

Open system: matter and energy can exchange with surroundings
beaker of water- water can evaporate

Closed system: only energy can exchange with surroundings
Sealed beaker of water

Isolated system: system where nothing can exchange with surroundings
Sat Feb 02, 2019 6:52 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capactiy
Replies: 5
Views: 141

### Re: Heat Capactiy

It depends on the amount of substance/ material so it’s an extensive property.
Wed Jan 30, 2019 1:07 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Qsystem+Qsurr=0?
Replies: 6
Views: 283

### Re: Qsystem+Qsurr=0?

If one loses heat, that heat will be gained by the other. The loss will equal the gain, which makes sense.
Wed Jan 30, 2019 1:03 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Regular heat capacity: why?
Replies: 4
Views: 136

### Re: Regular heat capacity: why?

Specific heat capacity is an intensive property. You'll get the specific heat capacity if you divide heat capacity by the amount of substance present (g), so it is a more useful property for calculations.
Tue Jan 22, 2019 11:22 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: What Happens to a Reaction if Inert Gas is Added?
Replies: 7
Views: 366

### Re: What Happens to a Reaction if Inert Gas is Added?

there is no change
Sun Jan 20, 2019 9:40 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: pressure and volume
Replies: 5
Views: 131

### Re: pressure and volume

Volume and pressure are inversely related.
Sun Jan 20, 2019 9:37 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and K
Replies: 10
Views: 312

### Re: Q and K

If Q < K, then [R] > [P] and forward reaction is favored
If Q > K, then [R] < [P] and reverse reaction is favored
Q=K then reaction is at equilibrium
Sun Jan 20, 2019 9:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Shortcut method (finding concentration change)
Replies: 5
Views: 139

### Re: Shortcut method (finding concentration change)

I think you might mean ignoring the -x subtraction in the change. So if Kc=[x][x]/0.5-x, and let's say our kc= 25, to find x you'd set up the equation as [x][x]/0.5-x= 25. In order to avoid the quadratic equation calculations, you can ignore the -x in the denominator, which won't affect the entire v...
Mon Jan 14, 2019 4:23 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction Quotient Value
Replies: 5
Views: 100

### Re: Reaction Quotient Value

If Q < K, then [R] > [P] and forward reaction is favored
If Q > K, then [R] < [P] and reverse reaction is favored
Q=K then reaction is at equilibrium
Mon Jan 14, 2019 4:19 pm
Forum: Ideal Gases
Topic: Using Kc or Kp
Replies: 13
Views: 338

### Re: Using Kc or Kp

Kp is used for gases, and Kc for concentrations. Sometimes Kc is used for gases as well, it depends on the question.
Mon Jan 14, 2019 4:13 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp
Replies: 7
Views: 206

### Re: Kp

I think any unit is fine as long as it's consistent throughout the equation.
Fri Dec 07, 2018 3:38 pm
Forum: Biological Examples
Topic: Hemoglobin Question
Replies: 2
Views: 225

### Re: Hemoglobin Question

Hemoglobin is an oxygen transporting protein in the blood. It's made out of four myoglobin molecules, each binding to one O2 molecule. Myoglobin alone transports one O2 in muscle cells, and hemoglobin transports 4 O2 molecules in the blood stream. Can someone explain the heme structure though? I mis...
Fri Dec 07, 2018 3:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent molecular geometry
Replies: 3
Views: 205

### Re: Bent molecular geometry

Yes, they both are bent, it's just that AX2E has an angle <120, and AX2E2 is <109, so the 2 lone pairs are just providing more repulsion than the one lone pair.
Fri Dec 07, 2018 3:23 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate Acids and Bases
Replies: 1
Views: 80

### Re: Conjugate Acids and Bases

When a base and an acid react, they produce a conjugate base and a conjugate acid. I will attach an image to help explain the concept.
Sat Dec 01, 2018 7:35 pm
Forum: Naming
Topic: Spaces in naming
Replies: 2
Views: 92

### Re: Spaces in naming

I mean if it helps to keep the spaces and then rewrite it it's fine, I don't think it's minus points either way. I think for your question it's yes, but please someone correct me if I'm wrong.
Sat Dec 01, 2018 7:23 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Water molecules
Replies: 9
Views: 351

### Re: Water molecules

The hydrogens in water are partial positive, so they will form hydrogen bonds with any of the NOF atoms charged partial negative.
Sat Dec 01, 2018 2:13 pm
Forum: Biological Examples
Topic: Knowledge of Biological Applications for Final
Replies: 5
Views: 123

### Re: Knowledge of Biological Applications for Final

I think he focused a lot on the chemo drug, other than that not sure
Fri Nov 23, 2018 9:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AX2E2
Replies: 2
Views: 72

### Re: AX2E2

The lone electrons cause the entire molecule to bend. AX2 alone is linear, AX2E2 adds the lone pair which causes strong repulsion.
Wed Nov 21, 2018 12:29 pm
Forum: Hybridization
Topic: bonds
Replies: 4
Views: 69

### Re: bonds

A sigma bond is a single bond, so every bond is a sigma bond.
Whenever another bond is added, it's called a pi bond.
sigma=single bond
sigma and pi=double bond
1 sigma and 2 pi=triple bond
Tue Nov 20, 2018 12:31 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape Importance
Replies: 1
Views: 52

### Re: Molecular Shape Importance

Having a lower boiling point means that the bonds of a certain molecule break easier than a molecule that has stronger bonds and attractions. A spherical molecule would have less surface area of bonds and interactions than a rod shaped molecule, which has much more surface area to bond.
Sat Nov 17, 2018 11:56 pm
Forum: Dipole Moments
Topic: How to Identify Dipole Moments
Replies: 3
Views: 146

### Re: How to Identify Dipole Moments

partial negative and partial positive charges.
Thu Nov 15, 2018 11:31 pm
Forum: Bond Lengths & Energies
Topic: Bond Length
Replies: 6
Views: 190

### Re: Bond Length

Yes that's right, also I wanted to add that a single bond will be longer than a double bond, and the double bond will be longer than the triple: all because multiple bonds will be shorter. The stronger the bond, the shorter length, and the stronger the attraction.
Thu Nov 15, 2018 11:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angle
Replies: 4
Views: 96

### Re: bond angle

You have 90° and 180°
Sun Nov 11, 2018 1:42 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 4
Views: 204

### Re: Electronegativity

Not sure, but I think it only has to do with the type of bonds not the actual shape. Also the greater the difference in electronegativity the larger the dipole.
Someone correct me if I'm wrong.
Sat Nov 10, 2018 11:56 pm
Forum: Electronegativity
Topic: Electronegativity and Electron Affinity
Replies: 4
Views: 199

### Re: Electronegativity and Electron Affinity

electron affinity: is the energy released when an electron is added to an atom
electronegativity: ability of an atom to attract an electron
Sat Nov 10, 2018 5:53 pm
Forum: Limiting Reactant Calculations
Topic: Actual Yield
Replies: 7
Views: 585

### Re: Actual Yield

Theoretical yield is calculated from the experiment with any errors that might occur, and actual yield is what's supposed to be the outcome, excluding any small errors. Percent Yield= actual/theoretical x100.
Sat Nov 03, 2018 10:06 pm
Forum: Trends in The Periodic Table
Topic: Cation and Anion Ionic Radius
Replies: 3
Views: 68

### Re: Cation and Anion Ionic Radius

When an atom loses an electron it's more positively charged, so there will be more attraction between the positive and negative charge of the electrons left there, stronger attraction means smaller radius --> smaller cation. When an atom gains an electron, it causes increased electron-electron repul...
Sat Nov 03, 2018 9:56 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Replies: 1
Views: 320

### Re: Radial vs. Angular Nodes

l=n-1. That determines the number of nodes present. if l=0, then it's a radial node (spherical and symmetrical node, s-orbital). When l is greater than 0, angular nodes will also be present in addition to other types of nodes. The angular nodes are the planes that show the p-orbital (the infinity sh...
Sat Nov 03, 2018 9:35 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: H-Atom Calculation
Replies: 2
Views: 277

### Re: H-Atom Calculation

I think the second equation is derived from the first. For the exams do the calculation using ΔE= Ef-Ei. Where you find the difference of the energy by doing two calculations (final and initial energy) using the equation En=-hR/n^2.
Sun Oct 28, 2018 10:54 am
Forum: Lewis Structures
Topic: Lewis Structures in Ionic Bonds
Replies: 2
Views: 65

### Re: Lewis Structures in Ionic Bonds

Yes we do, make sure to know the number of valence electrons of each group, and you can do that by just looking at the periodic table.
Sat Oct 27, 2018 7:45 pm
Forum: Ionic & Covalent Bonds
Topic: Lowest Ionization Energy [ENDORSED]
Replies: 7
Views: 283

### Re: Lowest Ionization Energy[ENDORSED]

You can know the lowest ionization energy of elements by where they are on the periodic table. Left to right across a period, and upward within group indicate increasing ionization energy.
Sat Oct 27, 2018 7:36 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Hydrogen’s Energy
Replies: 1
Views: 133

### Re: Hydrogen’s Energy

The Balmer and Lyman series equation can be derived from the equation E=-hR/n^2, so yes they both give the same values. For this course, I think Dr. Lavelle and the TAs want us to use the first equation (E=-hR/n^2), just because it practically makes more sense. So when we find the energies, we can d...
Mon Oct 22, 2018 1:21 pm
Forum: Properties of Light
Topic: Visible Light
Replies: 5
Views: 128

### Re: Visible Light

It's between 400 and 700 nm. Also, I attached an image that shows the ranges for the radiations.
Sun Oct 21, 2018 1:27 pm
Forum: Quantum Numbers and The H-Atom
Topic: 4th quantum number
Replies: 2
Views: 111

### Re: 4th quantum number

The fourth one gives the orientation of the spin of the electrons, there can be two values +1/2, and -1/2. the positive value indicates a clockwise spin, and the negative indicates an counter clockwise. So what this means in general is that electrons are spinning themselves as they orbit around the ...
Sun Oct 21, 2018 1:19 pm
Forum: Significant Figures
Topic: Sig figs and percentages
Replies: 3
Views: 495

### Re: Sig figs and percentages

Percentages do not count as sig figs. In your example, the answer would have the least number of sig figs, which is 2.
Sat Oct 13, 2018 7:13 pm
Forum: Photoelectric Effect
Topic: Example from Class- Photoelectric Effect
Replies: 2
Views: 64

### Re: Example from Class- Photoelectric Effect

What we did in class, we combined the two equations, E=hv and c=λv. Solving for λ would give you λ=c/v, and solving for v in the first equation will give v=E/h. Substitute the v into the λ equation, which will give λ=hc/E. Once you have this equation, plug in all your given. λ=(6.626*10^-34 Js)(3.00...
Sat Oct 13, 2018 6:58 pm
Forum: Properties of Light
Topic: De Brogile Equation
Replies: 6
Views: 81

### Re: De Brogile Equation

The concept is that particles exhibit wave-like properties, λ = h/mv; where h is planck's constant, m is mass, v is velocity (use SI units). Also what was mentioned in class is that if the wavelength is less than 10^-13-18 m, it is not considered to be a wavelength property.
Sat Oct 13, 2018 5:25 pm
Forum: Properties of Electrons
Topic: Spectral Lines (Balmer Series & Lyman Series)
Replies: 3
Views: 92

### Re: Spectral Lines (Balmer Series & Lyman Series)

The lyman series are the ultraviolet region, and the Balmer series are the visible region. The difference is where the electron lands after being excited, for balmer it's n=2, and for lyman it's at n=1. And yes drawing the picture does help to remember.
Sun Oct 07, 2018 12:24 pm
Forum: Molarity, Solutions, Dilutions
Topic: dilutions? [ENDORSED]
Replies: 5
Views: 187

### Re: dilutions?[ENDORSED]

M1V1=M2V2 is the main equation for dilutions! M=n(mol)/v(l) and you can move the equation around depending on your given in the problem. Also make sure all the units are the same in your equation.
Tue Oct 02, 2018 11:58 pm
Forum: Molarity, Solutions, Dilutions
Topic: Units when calculating volume
Replies: 4
Views: 275

### Re: Units when calculating volume

Molarity is always given in mol/L. In a problem if you're given a value for molarity, it will be in the units mol/L, so it becomes a problem when you don't convert to liters since now you're using two different units. So, I'd say convert any given volume to Liters if you're given a value for Molarit...
Tue Oct 02, 2018 11:25 pm
Forum: Empirical & Molecular Formulas
Topic: Using the Mass Spectrum in F17(b)
Replies: 2
Views: 328

### Re: Using the Mass Spectrum in F17(b)

You're dividing molecular mass by empirical to find the actual number of atoms in the formula (molecular formula). When you get that number (in this problem it's 907/302.24=3), you multiply it by the number of atoms in the empirical formula. So we go from C4O4Os to C12O12Os3.