CHEMISTRY COMMUNITY

KHuang1L

Bimolecular means there are two species involved in the elementary step.

KHuang1L

Activation energy is the amount of energy required for reactant particles to collide. It is represented as the amount of energy between the transition state point and reactant or intermediate step.

KHuang1L

The rate law is determined by the rate determining step. If there are intermediates involved, then modify the rate law so that they are not included.

KHuang1L

Kinetics helps us determine the rate of the reaction, while thermodynamics is used to determine whether the reaction is favorable.

KHuang1L

It does not matter. But using log is more convenient when calculating for pH.

KHuang1L

Should be specific to the question

KHuang1L

You would have to identify the half reactions and then use the standard E value of the half reactions to calculate the standard E cell value. If the E cell value is positive, then the reaction is spontaneous. If the E cell value is negative, then the reaction is not spontaneous.

KHuang1L

It could just be a typo.

KHuang1L

Include H+ in the cell diagram when it participates in the half reactions.

KHuang1L

An oxidizing agent is what causes something else to be oxidized, this agent is also reduced. The reducing agent is what causes something else to be reduced, this agent is also oxidized.

KHuang1L

Material after the midterm up to week 7 material.

KHuang1L

Oxidation is the removing of electrons and reduction is the addition of electrons.

KHuang1L

Delta G = Delta G under standard conditions + RTlnQ is used when the reaction is not at equilibrium. When the reaction is at equilibrium, you use the equation delta G under standard conditions = -RTlnK because delta G is equal to zero and the equilibrium constant can be used.

KHuang1L

The reaction is spontaneous when delta G is negative and not spontaneous when delta G is positive.

KHuang1L

If the change in Gibbs free energy is positive, then the reaction is not spontaneous. If the change in Gibbs free energy is negative, then the reaction is spontaneous.

KHuang1L

The formula sheet has the unit conversion equation from L.atm to J. To convert cm^3 to L in your answer, the formula sheet also has the unit conversion equation from dm^3 to L.

KHuang1L

The formula sheet has unit conversion equations to get to J.

KHuang1L

The question will tell you whether it is a reversible or irreversible reaction. The work done will be different because they use different equations to calculate work. Reversible reaction: W=-PV. Irreversible reaction: W=-nrTln(V2/V1).

KHuang1L

Anything from what we learned in week 3 and week 4.

KHuang1L

U is internal energy and q is heat

KHuang1L

KHuang1L

State does affect enthalpy. That is why you need to add the enthalpy of the phase change for reactions where there is a phase change.

KHuang1L

No, but they are good practice.

KHuang1L

He said that when steam (around 100 degrees C) comes into contact with skin (around 25 degrees Celsius), it releases around 40.7kJ (vaporization energy) and an additional 5kJ (to change from 100 degrees C to 25 degrees C).

KHuang1L

X is negligible when K is less than 10^3. Also confirm that your approximation is valid if the X value is less than 5% of your initial concentration.

KHuang1L

Gibbs free energy shows whether the reaction is endothermic or exothermic. A negative Gibbs free energy means that the reaction is exothermic, while a positive value means that the reaction is endothermic. I think it may be good to know.

KHuang1L

Heat is required in endothermic reactions, so adding heat will further the reaction.

KHuang1L

You calculate K by using the concentration of the reactants and products when the reaction is in equilibrium. You calculate Q by using the concentration of the reactants and products when the reaction is or is not in equilibrium. That is why Q is sometimes greater or smaller than K.

KHuang1L

The question should specify whether to solve for Kp or Kc.

KHuang1L

Same formulas but they calculate for different things

KHuang1L

In the ligand worksheet that is on the class website, remember that ox, en, dien, and edta are all polydentate. So you would use bis and tris instead of bi and tri.

KHuang1L

The central atom should be the transition metal.

KHuang1L

You should remember both and that it is a polydentate so you would use bis or tris to indicate the number of en molecules.

KHuang1L

The examples in class had sp3d.

KHuang1L

There is one sigma bond in a single bond, one sigma bond and one pi bond in a double bond, and one sigma bond and two pi bonds in a triple bond.

KHuang1L

You evaluate how many regions of electron density there are (in this case there are three). So, you want a total of three hybrid orbitals, which is possible with sp2 hybridization.

KHuang1L

The atoms with higher electronegativity are delta negative and the atoms with lower electronegativity are delta positive. If the electronegativity does not cancel out, then the molecule will be polar.

KHuang1L

Boron is one of the element exceptions that do not follow the octet rule. It is between the element carbon (which is the first element by increasing atomic number that requires a full octet) and beryllium (an element that does not follow the octet rule). Therefore, it also doesn't require an octet.

KHuang1L

Yes, check the relative electronegativity of each atom, and if the electronegativity of the atoms do not cancel out, then the molecule is polar.

KHuang1L

You count the number of single regions of electron density to determine what molecular shape the molecule has. That means that single, double, and triple bonds are counted as just one region of electron density and count as one additional X.

KHuang1L

Tetrahedral means that there are four atoms bound around a central atom. Trigonal planar is when there are three atoms bound around a central atom. You can memorize the A, X, and E for each structure to better identify them in the future.

KHuang1L

The completely shaded wedges represent atoms that are coming out of the page, while the hatched wedges represent atoms that are going into the page.

KHuang1L

H and He are exceptions because they would rather get two valence electrons to fill the 1st shell or 1s shell. B is also an exception because it is between Br, which prefers to lose two electrons to have two valence electrons, and C, which prefers to gain electrons to have a full octet.

KHuang1L

The bond length for each N-O bond is an average of the bond lengths for all three resonance hybrids.

KHuang1L

The most stable configuration is one where you get as many formal charges equal to zero as you can. In the case that you cannot get all formal charges equal to zero, try to change it so that the sum of all the formal charges is zero. Also, try to put the negative formal charge on the more electroneg...

KHuang1L

E = hv gives you the energy per photon. If the question gives you the total amount of energy, then you can divide that by E to get the number of photons.

KHuang1L

Use the De Broglie equation when you are trying to find the wavelength of a particle with momentum, such as an electron. You do not use the equation for light, since photons dp not have mass.

KHuang1L

Professor Lavelle said that it does not matter what order you place the dots in class. However, you should make sure that there are at least 4 electrons before pairing them together.

KHuang1L

E is the energy of the photon. That equation is used to find the energy of a photon of light going at a certain speed. H is Planck's constant and v is the frequency of the electron. If E is equal to or greater than the threshold energy required to release an electron from an atom, then the electron ...

KHuang1L

Correct. If the energy of the photon is equal to the threshold energy (minimum energy required to release an electron) of the electron, then the electron is released with zero kinetic energy. If the energy of the photon is greater than the threshold energy, then the electron is released with positiv...

KHuang1L

Light has both particle and wave-like properties. Light has particle-like properties in the photoelectric effect and wave-like properties like diffraction through the double slit experiment.

KHuang1L

Threshold energy is basically the minimum energy required to remove an electron from an atom. The equation is energy from a photon = threshold energy + kinetic energy of the freed electron.

KHuang1L

He said just the wavelengths that he discussed during lecture, such as the wavelength range of visible light and UV light.

KHuang1L

Everything we learned last week up to today's lecture.

KHuang1L

Around 8 questions but with multiple parts. For this test there is not much emphasis on sig figs and units.

KHuang1L

It should be a whole number. First check to make sure that your work leading up to the empirical formula is correct.

KHuang1L

I like to begin by writing down all the elements and how many atoms there are in each side first, starting with elements in fewer molecules. Looking at those numbers, I add stoichiometric coefficients to balance the two sides.

KHuang1L

His lectures often go over the video modules, so you can also watch those.

KHuang1L

UA Office Hours are posted under "Peer Learning Sessions and Step-Up Program" in the class website.

KHuang1L

Molecules and formula units are not interchangeable. Formula units are used to describe ions in ionic compounds.

Search found 60 matches