CHEMISTRY COMMUNITY

Briana Lopez 4K

The equation for the second order integrated rate law is
kt + 1/[A]o = 1/[A]
where k is a positive slope in the straight line graph

Briana Lopez 4K

The slow step requires more energy for the reaction to achieve, and in turn, more time which is why it is the rate-determining step

Briana Lopez 4K

For instance, a liquid or solid would not affect the rate

Briana Lopez 4K

when given pKa and asked for ph, solve for Ka with pKa= -logKa which would mean 10^(-pKa)= Ka Then, if the reaction is acidic, find the Ka equilibrium equation for the reaction Usually, an initial Molarity will be given for the Reactant Once the Ka equation is written, set it equal to the Ka value c...

Briana Lopez 4K

That heating curve is specific to water. Other molecules would have different heating curves and heat capacities.

Briana Lopez 4K

The integrated rate law for a second-order reaction is
kt + 1/[A]o = 1/[A}

The graph has a positive k, straight line slope which means that over time concentration of A is increasing

For the general rate law, the units for K would be 1/(M * s)

Briana Lopez 4K

The slope is -k because the integrated rate law for zero order is
-kt + [A]o = [A]

similar to the straight line y= mx + b

[A] = -kt + [A]o

Briana Lopez 4K

This is because OH- is used specifically for alkaline or basic solutions. Whereas H+ is associated with acidic solutions

Briana Lopez 4K

For mmols you would need to divide by 1000 because 1000 mmols equals 1 mol. As long as they all have the same units, then the problem should be fine

Briana Lopez 4K

Also, the slowest step is the one that requires the most energy to overcome such as the Activation Energy

Briana Lopez 4K

In an alkaline solution OH- is used to balance the number of oxygen and hydrogen atoms on both sides. Then electrons are used to balance the charge

Briana Lopez 4K

How do you use the 5% rule if there is more than one reactant? In the example in class it was CH3COOH-> H30+ + CH3COO- and the percentage is calculated by dividing (1.3 x 10^-3)/(0.10) * 100% which equals 1.3% but how would you do it if it were this for instance?? 2N2 + O2 —> 2N2O and our x= 7.15 x ...

Briana Lopez 4K

Also, when a reaction is said to be at equilibrium, it means that the products and reactants are being produced at the same rate. A chemical reaction at equilibrium represents a fixed P/R=K ratio. K is independent of concentration which means it will not change when there is more of one product or r...

Briana Lopez 4K

Additionally, when using Kp, partial pressure has to be calculated where when Kc is used, the concentrations have to be calculated

Briana Lopez 4K

A molecule as a whole can be Non-polar with polar bonds as long as they cancel out mmhm. Having one dipole movement makes it polar molecule if there is nothing to cancel out with it. so
C-Cl is polar bc of EN diff
but Cl-C-Cl is nonpolar because two dipole movements cancel out

Briana Lopez 4K

Additionally, it is also when there is a difference in electronegativity great enough for it to be a polar bond. Nonpolar molecules have no dipole movements because the electrons are shared equally, so there are no partial charges. Polar bonds have partial charges because there is an unequal sharing...

Briana Lopez 4K

Why is CH3COOH a stronger acid than CH3OH?

Briana Lopez 4K

Dr. Lavelle said in the lecture today that salts do not affect the pH of water. Why is this? And how is related to not affecting the boiling point as well?

Briana Lopez 4K

Also, since acids donate hydrogen ions, if the product has less hydrogen than the one in the reactant side, then it is easier to determine the acid.

Briana Lopez 4K

Also, the bonds for a strong acid are very easy to break when they are dissociated in water. This means that the H+ ions will lose an electron and it will go to the other element, the weak conjugate base. EX: HCL -> H+ + Cl- Strong Acid -> H+ + Weak Conjug Base ->this WCB is stable and unreactive be...

Briana Lopez 4K

Yeah, he larger the difference in Electronegativity, the more powerful the dipole moment. Also, if there is a strong dipole moment and there is a very unfair sharing of electrons, then the bond is weaker. This is why polar bonds are weaker than nonpolar bonds. Equal sharing = stronger bond= nonpolar...

Briana Lopez 4K

In class, he said something about how it is written differently, but the more clear way is sp3d

Briana Lopez 4K

What does Ka represent and why is it significant?

Briana Lopez 4K

It will also form double or triple bonds to become more stable

Briana Lopez 4K

Vsepr.jpg A lone pair of electrons repels more than a bonded pair of electrons because LPE are less stable and have more energy. An electron bond and a lone pair are both considered regions of electron density, and regions of e- density repel. The LPE repel more which means that the bond angles wil...

Briana Lopez 4K

The lone pairs are not shown, but if it were, then one would most likely be on top and the VSEPR would be AX2E1. The bond angle would be less than 120, but all of the angles would be about that much.

Briana Lopez 4K

London forces are AKA Dispersion forces, Induced Dipole-Induced Dipole, and Van der Waals forces. They occur when there is an uneven distribution of electrons causing a temporary dipole moment and temporary partial charge. This temporary dipole creates another dipole called a temporary induced dipol...

Briana Lopez 4K

Yes, the arrow would go towards the more EN atom.
an example would be H2O, since O is more EN than H the arrow will point towards O

Briana Lopez 4K

A nonpolar molecule will have no charge and a polar molecule will have partial charges. A partial negative would go on the more EN side and a partial positive would go on the less EN side of the molecule because the electron concentration goes more towards the more EN element.

Briana Lopez 4K

The way to identify a radical would be if the molecule has an uneven number of electrons and at least one unpaired electron

Briana Lopez 4K

Since Cl has 7 valence electrons and only needs 1 more to complete its octet, once it obtains an electron to become Cl-, is it more stable as this ion? And does stability mean that it is less reactive?

Briana Lopez 4K

Yeah we don't have to worry about those for now. The other 3 are though (s, p, d) (sphere, propeller, daisy)

Briana Lopez 4K

Amplitude relates to the intensity of the light. If there is a higher wavelength, then there are more photons and a brighter light.

Briana Lopez 4K

is this for the energy per photon equation?
E= ch/λ?

Briana Lopez 4K

The shapes are... s is a "sphere", p is a "propeller", d is a "daisy" and f is irrelevant right now

Briana Lopez 4K

Yeah I believe the equation for power is force x velocity

Briana Lopez 4K

ΔE=Ef-Ei
En= -hR/n^2

ΔE= -hR/nf^2 - (-hR/ni^2)
ΔE= hR/ni^2 - hR/nf^2

V=R(1/ni^2 - 1/nf^2)
ΔE/h= R(1/ni^2 - 1/nf^2)
ΔE=hR(1/ni^2 - 1/nf^2)
ΔE=hR/ni^2 - hR/nf^2

Briana Lopez 4K

The P in p=mv stands for momentum. The equation for Power is Force x Velocity. In a case where we are only given momentum, I think we can solve for Kinetic energy ( E=threshhold+KE ) if we substitute other equations for E and get it in terms of p=mv E = threshold + KE hv = threshold + KE KE = hv - t...

Briana Lopez 4K

I had trouble with that one too for the same reason. I assumed it was from n=1 to n=2, but wasn't sure.
The formula I used was the En= -hR/n^2 which I believe is the same as the V= R((1/n1^2)-(1/n2^2))

Briana Lopez 4K

Thank you this is helpful., also i think the mass of an electron is 9.10938356 × 10-31 kilograms

Briana Lopez 4K

It is important to just keep in mind that increasing the intensity of light does not cause electrons to be ejected

Briana Lopez 4K

I don't know a good song, but PLF said a way to help memorize the v= c/λ is
"Hey what's new? :D....speed of light over lambda" Haha I'd say it's pretty cute

Briana Lopez 4K

Also, this may come in handy when we start using them more, but it was mentioned in class how the final answer should have the least amount of significant figures. If one part of the problem has 3 sig figs and the other part has 6 sig figs, then I think your final answer should be rounded to 3 sig f...

Briana Lopez 4K

Mole/s is the spelled out version of the abbreviations "mols" and "mol".
For example, Millimeter would be abbreviated as "mm"
In problems, usually abbreviations are used, so the "mol"

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