CHEMISTRY COMMUNITY

Drew Myers 4G

How does a change in the activation energy affect the rate constant?

Drew Myers 4G

What is catalysis?

Drew Myers 4G

What is the pre-equilibrium method for determining the reaction rate?

Drew Myers 4G

What is the frequency factor, and how is it determined?

Drew Myers 4G

What is the relationship between temperature and the reaction rate?

Drew Myers 4G

How do catalysts speed up reactions?

Drew Myers 4G

What is the difference between adsorption and absorption?

Drew Myers 4G

When Lavelle said “microscopic reversibility is being assumed” in regards to the rate constants, k and k’, what does he mean?

Drew Myers 4G

What is molecularity?

Drew Myers 4G

How do you know what step in a rxn mechanism is the slow/fast step? What does a slow/fast step even mean?

Drew Myers 4G

Can someone give an example of an elementary step that has bimoleuclar molecularity and give its rate law?

Drew Myers 4G

Can someone give an example of an elementary step that has termolecular molecularity and give its rate law?

Drew Myers 4G

What exactly is a reaction mechanism?

Drew Myers 4G

How do you derive the 2nd order integral rate law?

Drew Myers 4G

Can someone explain what each of the variables in the Arrhenius equation represent?

Drew Myers 4G

How do you get to ln[R] = -kt + ln[R]initial from -(1/a)(d[R]/dt) = k[R]^n (where n = 1)?

Drew Myers 4G

How do you get the unique rate from aR -> bP (with R being reactants and P being products)?

Drew Myers 4G

How do you use the method of initial rates to determine n and k?

Drew Myers 4G

What do all the variables in the Nernst equation mean?

Drew Myers 4G

What do the variables in deltaG = -nFE(cell) all mean?

Drew Myers 4G

How does concentration affect cell potential?

Drew Myers 4G

Are deltaS and deltaH considered constant when comparing a reaction at two different temperatures, or are other variables in the equation constant?

Drew Myers 4G

In the Van’t Hoff equation, is the K temperature or the equilibrium constant?

Drew Myers 4G

How do you know which part of a redox reaction is the oxidation?

Drew Myers 4G

How do you know which part of a redox reaction is the reduction?

Drew Myers 4G

Can someone explain what the variables in the equation stand for?

Drew Myers 4G

Can someone explain how to use calculus to prove
w = -PΔV?

Drew Myers 4G

When does entropy equal zero?

Drew Myers 4G

Can someone clarify how to prove when a reaction is spontaneous using Gibbs Free Energy?

Drew Myers 4G

Can someone explain what each variable represents in the Van’t Hogg Equation?

Drew Myers 4G

Can someone give a definition of the first law of thermodynamics?

Drew Myers 4G

How do you solve this question? It tells you the initial temperature of the water (at 400g), and the initial temperature of the ice (at 50.0g), so how do you find the final temperature when given that information?

Drew Myers 4G

I’m confused as to how to start this question. It tells you that deltaV=0, so from that I know deltaU = q. Beyond that, I have no idea what to do.

Drew Myers 4G

Can someone differentiate an open, closed, and isolated system?

Drew Myers 4G

When does delta U only equal to q (when does w = 0)?

Drew Myers 4G

How do you solve this problem since it only gives you pKa and asks for the ranking of them as a base?

Drew Myers 4G

What are the equations that are equivalent to Kw (1.0 x 10^-14)?

Drew Myers 4G

Can someone give a quick explanation of how to use Method Three as explained in lecture?

Drew Myers 4G

Can someone give a quick explanation of how to use Method 2 as explained in lecture?

Drew Myers 4G

Can someone give a quick explanation of how to use Hess’s Law?

Drew Myers 4G

What happens to K when the temperature changes as a result of the reaction being endothermic?

Drew Myers 4G

What happens to K when the temperature changes as a result of the reaction being exothermic?

Drew Myers 4G

What happens to K when you change the pressure?

Drew Myers 4G

What happens to K when you change the volume?

Drew Myers 4G

What happens to K when you change the amount of product or reactant?

Drew Myers 4G

Why do we not include solids or liquids when calculating K?

Drew Myers 4G

When do we use Q, and when do we use K?

Drew Myers 4G

Why are there no units for K?

Drew Myers 4G

What does each variable in PV = nRT stand for?

Drew Myers 4G

When are we supposed to use Kp, and when are we supposed to use Kc?

Drew Myers 4G

After figuring out that the chemical equation is: H2O2 + SO3 -> H2SO5, you can determine that H2O2 is the Lewis base as it is the lone pair donor and SO3 is the Lewis acid as it is the lone pair acceptor.

Drew Myers 4G

In part C, why do the NH groups act amphoteric?

Drew Myers 4G

How do you know if an acid is weak?

Drew Myers 4G

Why is NH3 monodentate?

Drew Myers 4G

The easiest way to find the oxidation number is to substract the overall charge of the ligands from the overall charge of the coordinate compound.

Drew Myers 4G

How does one differentiate between inorganic and organic acids?

Drew Myers 4G

How does one differentiate between inorganic and organic bases?

Drew Myers 4G

Are Bronsted bases and acids determined based solely on if a proton is donated or accepted?

Drew Myers 4G

Acids are proton donors and bases are proton acceptors.

Drew Myers 4G

What is an amphoteric compound, and what are some examples?

Drew Myers 4G

Does anyone have an easy way to memorize the trends in the periodic table?

Drew Myers 4G

What is the best way to calculate quantum numbers?

Drew Myers 4G

What exactly does heisenberg’s equation mean empirically?

Drew Myers 4G

What exactly does lambda = h/p mean empirically?

Drew Myers 4G

What exactly does E = hv mean empirically?

Drew Myers 4G

Am I right in saying that all molecules have london dispersion forces? If so, why is this the case?

Drew Myers 4G

What kinds of molecules are bonded with an ion-dipole molecular force?

Drew Myers 4G

Which atoms can have hydrogen bonds?

Drew Myers 4G

Sigma bonds are formed by head to head overlapping orbitals, whereas pi bonds are formed by the lateral overlapping. Additionally, sigma bonds are stronger than pi bonds. Lastly, sigma bonds can be formed between both s and p orbitals whereas pi bonds are mostly formed between p and d orbitals.

Drew Myers 4G

Sigma bonds are formed by head to head overlapping orbitals, whereas pi bonds are formed by the lateral overlapping. Additionally, sigma bonds are stronger than pi bonds. Lastly, sigma bonds can be formed between both s and p orbitals whereas pi bonds are mostly formed between p and d orbitals.

Drew Myers 4G

Is the presence of the d-block the reason why atoms such as Xenon can go beyond the octet rule?

Drew Myers 4G

So just to be sure, electronegativity follows the same trend as ionization energy and electron affinity on the periodic table right? If not, what trend does it follow?

Drew Myers 4G

All compounds can have an instantaneous dipole moment (even ions) meaning that London Forces exist for all compounds.

Drew Myers 4G

The main difference between the two is that dipole-dipole forces occur among molecules with dipole moments whereas London forces occur due to instantaneous dipoles that form in atoms or nonpolar molecules. I'm not sure how exactly you can tell if a compound has a dipole-dipole force from the chemica...

Drew Myers 4G

A dipole is a pair of equal and oppositely charged or magnetized poles separated by a distance.

Drew Myers 4G

No. It depends on the radii of the elements themselves.

Drew Myers 4G

Yes. Ionization energy and electron affinity positively correlate with electronegativity since the periodic trends align.

Drew Myers 4G

Are longer bonds or shorter bonds stronger?

Drew Myers 4G

How exactly are we supposed to draw ionic compunds? I know it was briefly addressed in class, but I’m still confused.

Drew Myers 4G

Why are some atoms able to break the octet rule and accept more than 8 valence electrons?

Drew Myers 4G

The reason for the effect is the inertness of the inner s electrons due to poor shielding.

Drew Myers 4G

The first ionization energy for sulfur and phosphorus atoms are nearly the same, despite sulfur having a larger Zeff; this is due to greater electron-electron repulsions in S, making the energy of the outermost electrons higher than predicted. Once the first electron is removed, the Zeff becomes the...

Drew Myers 4G

Since 4s orbitals have lower energy, they are filled first. When 3D orbitals are filled, 4s is no longer lower in energy.

Drew Myers 4G

For part A, see if the quantum numbers are invalid. n=4, which means l can only be 0,1,2, or 3, and since it’s 2, l is valid. M(l) can only be -l through l, so it is valid as it is -1. Lastly, m(s) can be either -1/2 or +1/2, so it is valid. For part B, it is not possible because l = 0, so m(l) must...

Drew Myers 4G

S-block metals have lower ionization energies than p-block metals, which means that s-block metals tend to form cations as they are more willing to give away electrons. Thus, they are more reactive.

Drew Myers 4G

The amount of energy is not what causes the photoelectric effect. It is caused by the wavelength of the light used.

Drew Myers 4G

E represents the energy of the photon. The energy required to remove an electron is known as the work function/threshold energy and is not present in this equation.

Drew Myers 4G

When doing electron configurations for multi-electron atoms, do we always use the noble gas of the previous line to shorten the configuration? Why can't we use the atom that comes before the atom we're doing the configuration for?

Drew Myers 4G

So after hearing both a lecture and a discussion section about this equation, I am still incredibly confused as to what its purpose/use is. What is the purpose of this equation?

Drew Myers 4G

After doing a little online research, the s, p, d, and f letters do have a history that can be discovered through this link: https://pubs.acs.org/doi/pdf/10.1021/ed084p757

Drew Myers 4G

What is the mass of a neutron, and when will we need to use it in this chapter/ever?

Drew Myers 4G

What is the order of energy from increasing to decreasing of gamma rays, x rays, UV light, visible light, and microwaves?

Drew Myers 4G

Will there ever be a time where we need to use megagrams or gigagrams or will we likely only go as big as kilograms?

Drew Myers 4G

The energy required to remove an electron is the work function, which they give you as 150.6 kJ/mol. All you need to do is convert that value into Joules, which is done by multiplying 150.6kJ/mol x 1000 g/kg = 150600 J/mol. Then divide that value by Avogadro's number (6.022 x 10^23 molecules/mol) to...

Drew Myers 4G

As you said, there are no other differences than them being in the visible light and UV regions (which also means that they have different wavelengths).

Drew Myers 4G

For problem M15 part B, how would you determine the mass of aluminum chloride that can be produced by the reactants? My answer is different from the one in the odd numbered examples solutions and I don't know why.

Drew Myers 4G

To find the stoichiometric coefficients, simply balance the chemical equation.
Before balance: Ca + H2O -> H2 + Ca(OH)2
Balanced: Ca + 2H20 -> H2 + Ca(OH)2
The stoichiometric coefficients are 1, 2, 1 and 1.

Drew Myers 4G

In order to get the volume needed, you must first find the molarity of Na2CO3 : (2.111g)/(105.99g.mol^-1 x 0.2500L) = .07967 mol Na2CO3. From there, determine the mol of Na+ ions present in Na2CO3 (there are 2). Then, solve for the volume by dividing the mol of Na+ given by the molarity found before...

Drew Myers 4G

In order to find the mol K+ in the problem, you have to first convert the .500 g KCl, K2S, and K3PO4 into mol instead of grams using their molar masses which can be determined from the periodic table. After doing so, look at each compound and see how many mol of potassium ions are in each (KCl has 1...

Drew Myers 4G

Imagine that a problem asks you to find the percent yield but wants 2 sig figs, and the end answer you get is 63.5%. Would that round up to 64% or down to 63%, and why?

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