CHEMISTRY COMMUNITY

MelanieAu1G

This is because the rate constant, k, increases exponentially as temperature, T, increases. Therefore, the rate constant for the forward reaction that correlates with the larger activation potential will increase more so than the smaller rate constant for the reverse reaction. This would also mean t...

MelanieAu1G

For the ln in the NERNST equation, you know that you need to put a 1 in the numerator and either 20 and 30 in the denominator, respectively, because the problem tells you that the concentration of ions on the inside of the cell is about 20 to 30 times that of the concentration outside. We know that ...

MelanieAu1G

When considering the conformations of molecules (e.g. alkanes, alkenes, and alkynes), torsional strain is defined as the force that opposes rotation of a part of a molecule about a bond. Today, Dr. Lavelle used the analogy of a wrench as an example to demonstrate what it is similar to; think of the ...

MelanieAu1G

The pseudo equilibrium constant is not the actual equilibrium constant, it is more of a reference point for the reaction as it reaches equilibrium. The concentration of the activated complex of AB is used because the equation states A + B -> AB -> C. Consider the reaction profile graph, in which in ...

MelanieAu1G

When writing a rate law, the reaction order corresponds to the degree of the concentration. If the concentration of any given element is raised to an exponential power, that power is its order, and this is determined by the number of moles of the element present in the reaction (thus generally occur...

MelanieAu1G

Stoichiometric coefficients, or the number of moles of a product or reactant, affects K and Q values. When determining the exponents for each reactant in a rate law, you must analyze information given about the concentration of each reactant and its correlation to the corresponding rate.

MelanieAu1G

It depends primarily on the conditions that they are asking you about the entropy under. If they are asking you about entropy at 0 K, there is no thermal entropy to consider, therefore only residual entropy needs to be accounted for (this is based off of the number of positions/ arrangements for a m...

MelanieAu1G

Benzene has the chemical formula C6H6, while hexane has the chemical formula C6H14. Because they are asking you about the molar entropy at 25 C, we have to take into account thermal entropy (rather than residual/ positional entropy) and the fact that hexane would have more thermal entropy because it...

MelanieAu1G

Yes, however it is not true for entropy values at standard conditions.

MelanieAu1G

You somewhat answered your question in your question. We switch the reaction involving Mn because it is the oxidation half reaction, meaning that the charge of the products is being reduced and therefore that the electrons must be on the right side of the equation. Switching this equation also allow...

MelanieAu1G

The arrows that point to and from the same element have been added to assist you in identifying which bonds are broken and formed; this means that they are trying to highlight important bonding sites in which the bonds in the products differ from those in the reactants. You can still do the problem ...

MelanieAu1G

A photon checks into a hotel and is asked if he needs any help with his luggage.
He says, "No, I'm traveling light."

MelanieAu1G

Did you hear about the man who got cooled to absolute zero?

He's 0K now.

MelanieAu1G

Based on the molecule S02F2, there are six possible configurations of the four attached atoms around the central atom, S. Since we know that there are six possible arrangements, we can deduce that the degeneracy of this molecule is W=6, where W is degeneracy. The problem cites one molecule, SO2F2, s...

MelanieAu1G

Delta U is the change in internal energy of a system. The change in internal energy (dU) is equal to q+w, where q is the heat lost or gained and w is the work done on or by the system. (du=q+w) In the instance that the process occurs under constant pressure, du=dH+w, because qp=dH. If the process oc...

MelanieAu1G

In an irreversible reaction, the reactants convert to products, but the products cannot convert back to reactants (think of combustion, in which oxygen gas is burned with a compound; this process cannot be reverted/ reversed). In a reversible reaction the reactants and products are never fully consu...

MelanieAu1G

A "mock" calorimeter can actually be made out of any simple, insulating material (such as styrofoam). A common chemistry experiment involves creating a coffee cup calorimeter, literally making a calorimeter out of a styrofoam cup because the material acts as a good insulator. Bomb calorime...

MelanieAu1G

If the system to which you are referring is an isolated system, then yes, the mass of the entire system would remain the same despite shifts in state. This is because neither mass nor heat can escape the system and be emitted to the surroundings.

MelanieAu1G

The problem states specifically that we are finding the reaction enthalpy for the hydrogenation of ethyne and ethane. Hydrogenation is a process in which hydrogen and another compound/ substance react with each other; as a result, double bonds are converted to single bonds which "hardens" ...

MelanieAu1G

First, you need to right the equation for the reaction and then balance the equation. Once you have done that, you will have the correct molar ratios for this reaction (N2 (g) + 3H2 (g) <-> 2NH3 (g)). We are given the equilibrium concentration of NH3, therefore right that value in your ICE table in ...

MelanieAu1G

Did the solution also calculate Kp? It could be that the solution is trying to test if the reaction is at equilibrium or not. Q and Kp are calculated the same way, so calculating Q would theoretically be like calculating Kp if only a single condition/ state of the reaction is given. Either way, the ...

MelanieAu1G

This titration takes place between a weak acid and a strong base, therefore at the stoichiometric point the moles of the base added = the moles of acid in the sample (i.e. moles of HCOOH = moles of NaOH added) . Once we know this, we can derive the amount of moles of HCOO- based on molar ratios and ...

MelanieAu1G

I believe that anilinium chloride would still lower the pH of a solution because it is still an acidic salt, even with the presence of Cl-.

MelanieAu1G

Rachel's response is correct. The reason why the orbitals for N and O going are uneven with each other is because O is more electronegative than N. Because of is more electronegative than N, the orbitals require more energy to fill or remove electrons from, which is why they are located higher than ...

MelanieAu1G

When writing out the name of a compound, not the formula, ligand names are always written alphabetically in regard to the actual ligand, not the prefix indicating the number of ligands. In the course reader, writing chloro after ammine is correct because C comes after A. In the textbook, the compoun...

MelanieAu1G

Ligands are defined as Lewis bases attached to the central metal atom or ion in a d-metal complex (a complex being a species consisting of a central metal atom or ion to which a number of molecules or ions are attached by coordinate covalent bonds). Ligands can be either ions or molecules and they u...

MelanieAu1G

What would be the bond character of fluorine involved in a sigma bond, for example in CH3F? I attended a review session this past weekend in which the TA told me that the sigma bond characteristics between the carbon and fluorine atoms would be (C 2sp3,F 2p), respectively. His explanation for not ha...

MelanieAu1G

The effective nuclear charge (Zeff) is defined as the net nuclear charge after taking into account the shielding caused by other electrons in the atom. Zeff changes as the number of electrons in the atom changes; therefore, if there are fewer electrons in the lower energy orbitals, there will be les...

MelanieAu1G

Cl can have an expanded octet, and therefore form multiple double bonds with the oxygen atoms, because of its location in period 3 which allows for "extra" valence electrons to occupy (or "overflow" into) the 3d orbital. Cl's, and numerous other atoms in period 3 and other succee...

MelanieAu1G

The Heisenberg Indeterminacy Principle accounts for the fact that because we can never know the exact position and momentum (mass times the velocity) of a particle at any given time, there is still a way to estimate or consider those characteristics of a particle but to a certain extent. This indete...

MelanieAu1G

Yes, you are correct. There wavelengths are so close to each other in length, that the difference between the two is nearly indistinguishable (or rather, is indistinguishable to three sig. figs.). Your calculations are correct, therefore your answer would be that there is (almost) no noticeable diff...

MelanieAu1G

Generally speaking, yes, constants should be taken into account for significant figures. To determine how many significant figures to consider, use the number with the least amount of significant figures present, or provided, in a problem. Even though there may be a number with a greater amount of s...

CHEMISTRY COMMUNITY

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Re: Homework 15.65 part C

Re: 2015 Final 5A

Re: Torsional Strain

Re: Pseudo-Equilibrium Constant

Re: Reaction Mechanisms and Orders

Re: Stoichiometric coefficients

Re: Molar Entropies

Re: Winter Midterm 2014 QB

Re: DeltaG standard formation values

Re: Question 7 on Midterm 2013

Re: Winter 2016 Midterm Q1A

Re: Post All Chemistry Jokes Here

Re: Post All Chemistry Jokes Here

Re: Homework Question 9.25

Re: Delta U

Re: Reversible vs irreversible process

Re: Calorimeters [ENDORSED]

Re: Conservation of Energy Question

Re: Help on HW 8.57

Re: Example in Course Reader

Re: 2007 Final Question 5B

Re: 2012 Final Exam Q7B

Re: Acidic Salts

Re: Higher/lower energy in a MO diagram?

Re: Writing the formula of coordinate compounds

Re: Ligand formation

Bond Character of Fluorine

Re: Effective Nuclear Charge

Re: Lewis Structure for Perchlorate Ion [ENDORSED]

Re: What does Heisenberg Indeterminacy indicate with respect to the “randomness” of the electrons that are near nucleus

Re: 1.37 [ENDORSED]

Re: Constants and Significant Figures