CHEMISTRY COMMUNITY

Carine Tamamian 2B

yes it's H3PO4 with 3 protons

Carine Tamamian 2B

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.

Carine Tamamian 2B

the more positive reduction potential the higher the oxidizing power.

Carine Tamamian 2B

I think for this test, using Pt is the safest bet

Carine Tamamian 2B

Rate = k[A]^2[B]^2. You can use the coefficients as long as the reaction is an elementary reaction

Carine Tamamian 2B

because the faster rate is dependent on the slower one.

Carine Tamamian 2B

The 5% rule, so if your equilibrium value is smaller than 10^-3, you can ignore that x to make your calculation easier.

Carine Tamamian 2B

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.

Carine Tamamian 2B

Enzymes lower the activation energy.

Carine Tamamian 2B

I was confused about this as well. Sun is melting the ice, so it the ice has to be absorbing heat?
someone help, thanks

Carine Tamamian 2B

Pt is added when no conducting solids are present.

Carine Tamamian 2B

My TA said tomorrow after lecture, so just stay for the lookout afterwards.

Carine Tamamian 2B

Yes! it's products and reactants concentrations that affect the free energy.

Carine Tamamian 2B

This graph will help better visualize the concept!

Carine Tamamian 2B

I heard that it's not too bad, just busy work. It depends on what type of person you are!

Carine Tamamian 2B

Yes they are, and it's depending on whether the reaction is exothermic or endothermic.

Carine Tamamian 2B

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?

Carine Tamamian 2B

Depends on the units! L or J

Carine Tamamian 2B

Yes! Anything works because it counts as practice for the midterm.

Carine Tamamian 2B

Solids and liquids don't count because their pressure and volume aren't affected

Carine Tamamian 2B

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

Carine Tamamian 2B

It depends on the amount of substance/ material so it’s an extensive property.

Carine Tamamian 2B

If one loses heat, that heat will be gained by the other. The loss will equal the gain, which makes sense.

Carine Tamamian 2B

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.

Carine Tamamian 2B

there is no change

Carine Tamamian 2B

Volume and pressure are inversely related.

Carine Tamamian 2B

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

Carine Tamamian 2B

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...

Carine Tamamian 2B

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

Carine Tamamian 2B

Kp is used for gases, and Kc for concentrations. Sometimes Kc is used for gases as well, it depends on the question.

Carine Tamamian 2B

I think any unit is fine as long as it's consistent throughout the equation.

Carine Tamamian 2B

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...

Carine Tamamian 2B

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.

Carine Tamamian 2B

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.

Carine Tamamian 2B

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.

Carine Tamamian 2B

The hydrogens in water are partial positive, so they will form hydrogen bonds with any of the NOF atoms charged partial negative.

Carine Tamamian 2B

I think he focused a lot on the chemo drug, other than that not sure

Carine Tamamian 2B

The lone electrons cause the entire molecule to bend. AX2 alone is linear, AX2E2 adds the lone pair which causes strong repulsion.

Carine Tamamian 2B

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

Carine Tamamian 2B

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.

Carine Tamamian 2B

partial negative and partial positive charges.

Carine Tamamian 2B

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.

Carine Tamamian 2B

You have 90° and 180°

Carine Tamamian 2B

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.

Carine Tamamian 2B

electron affinity: is the energy released when an electron is added to an atom
electronegativity: ability of an atom to attract an electron

Carine Tamamian 2B

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.

Carine Tamamian 2B

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...

Carine Tamamian 2B

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...

Carine Tamamian 2B

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.

Carine Tamamian 2B

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.

Carine Tamamian 2B

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.

Carine Tamamian 2B

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...

Carine Tamamian 2B

It's between 400 and 700 nm. Also, I attached an image that shows the ranges for the radiations.

Carine Tamamian 2B

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 ...

Carine Tamamian 2B

Percentages do not count as sig figs. In your example, the answer would have the least number of sig figs, which is 2.

Carine Tamamian 2B

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...

Carine Tamamian 2B

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.

Carine Tamamian 2B

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.

Carine Tamamian 2B

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.

Carine Tamamian 2B

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...

Carine Tamamian 2B

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.

Search found 61 matches