CHEMISTRY COMMUNITY

ConnorThomas2E

You need two half reactions in order to write a cell diagram. The example you provided is a whole cell and it can be broken up into two half-cells. With the half reactions from this, you write the anode on the left side of the salt bridge and the cathode on the right side.

ConnorThomas2E

NO has greater residual entropy because its two atoms can result in the arrangement of two different molecules. It can either be NO or ON. However, the BF3 molecule only has one way it can be arranged. This is related to Boltzmann's formula for calculating residual entropy.

ConnorThomas2E

If the problem asks for you to find the total increase in the internal energy and then states that the internal energy returns to its original state, you see how much the internal energy increases by in the first step and then make it negative. However, the overall change in internal energy will be 0.

ConnorThomas2E

I don't think so. I think that you must put energy into the system in order to get it to react, and therefore it cannot produce energy that can be used as work.

ConnorThomas2E

For the cell diagram in HW 14.15 a, why is there a line instead of a comma between Ag(s) and AgBr(s)?

ConnorThomas2E

Will we need to know about the Michaelis-Menten Mechanism for the final?

ConnorThomas2E

Things that often lead to higher molar entropy are more complex structures (the bonds can absorb more vibration energy), heavier atoms, and formation of gas particles. Therefore, size and complexity are helpful to determine the molar entropy.

ConnorThomas2E

I think the processes are the same for both rate of formation and rate of decomposition. Just make sure that the equilibrium constant is correct.

ConnorThomas2E

When the molecules in a reaction collide with each other more, or if there is a higher frequency, then there is a greater chance that a reaction will occur. The molecules need to collide in order for the reaction to occur, and the having a high frequency increases collisions. Therefore, because more...

ConnorThomas2E

As said before, the rate constant is always proportional to K. Therefore, when K is very large, meaning the products are favored, you will have a large rate constant.

ConnorThomas2E

The graph of Zero order has time on the x axis and concentration on the y axis. Since the reaction rate is independent of the concentration, this graph will just be linear with a slope of -k.

ConnorThomas2E

You start with the initial concentration of A, and you need to find how much b is produced to see how much the concentration of A decreases. Therefore, you would subtract 2*b from the initial concentration of A

ConnorThomas2E

Something with a high reducing power will have a large negative potential difference. Something with a high oxidizing power will have a high positive potential difference.

ConnorThomas2E

Like said before, the tangent can be negative if the reverse reaction is occurring. In this case, the products will be decreasing in their concentration, meaning that they have a negative rate of change.

ConnorThomas2E

When you have a high activation energy, that means you will need a significant amount of energy in order for the reaction to occur. Often times, because you need more energy for the reaction, this will result in the time needed for the reaction to be completed being longer.

ConnorThomas2E

When you balance the half reactions, you will get the number of electrons that are either lost or gained depending on whether it is a reduction or oxidation reaction. When you add the two half reactions together, you will need to multiply the half reactions by a coefficient in order to end up with t...

ConnorThomas2E

I think it is used to change the units of deltaG. If n was not "pure", then the units of deltaG would be Joules, but if n was pure, then the units of deltaG would be Joules/mol. I'm not completely sure though

ConnorThomas2E

The standard cell potential is not changed because it is equal to deltaG/(n*F). Therefore, if you would double the reaction, you would end up doubling both deltaG and n, which would cancel out.

ConnorThomas2E

You multiply the standard reaction entropy for the molecule by the stoichiometric coefficient given to you by the reaction. It does not matter if it is a solid, liquid, or gas. you multiply the standard reaction enthalpy of each substance by the amount of moles of that substance that are used during...

ConnorThomas2E

It helps to think about the compound in terms of its gibbs free energy of formation. If the free energy of formation of a compound is negative, this means that in the reaction for the formation of the compound, the elements (reactants) will tend to combine to form the compound (products). On the oth...

ConnorThomas2E

For ideal gases, it is 5/2R at constant volume and 3/2R at constant pressure

ConnorThomas2E

It is a constant that the book provides you or that Dr. Lavelle will give to us before a test.

ConnorThomas2E

When deltG is negative, this means that a reaction is spontaneous. In this problem, when deltaG is zero, neither the forward nor reverse reaction are favored. However, even a slight increase in temperature above the temperature value that makes the deltaG zero will result in the favorability of the ...

ConnorThomas2E

The bond enthalpy method actually takes into account mean bond enthalpy. In different molecules, the amount of atoms attached to the central molecule, lone pair electrons, and etc. affect the strength of bonds. As a result, the same bond between two atoms in different molecules will have a different...

ConnorThomas2E

The enthalpy will be given to you often times in kJ/mole and often times you will be given the mass of the substance, so for these problems it is important that you change the mass of the substance into moles and then multiply it to the given enthalpy.

ConnorThomas2E

I think the answer is right. What you need to do is calculate the heat needed to first change the water's temperature using q=m*C*deltaT. After you add the amount of energy times the moles of water needed for the phase change.

ConnorThomas2E

Molar heat capacity is the heat required to raise the temperature of a mol of the substance, while the specific heat capacity is the heat required to raise hte temperature of a gram of the substance.

ConnorThomas2E

When the system is gaining energy through work, or when work is being done on the system from the surroundings, W is positive. when the system releases energy by doing work on the surroundings, W is negative.

ConnorThomas2E

In order to do this problem, you would first calculate the energies to break the bonds of 3 double bonded carbons and 3 single bonded carbons. You would then compare this value to 6 resonance carbon bonds, and see that the resonance structure requires more energy to break the bonds, and it is theref...

ConnorThomas2E

Hess' law states that a specific reaction is equal to the sum of the enthalpies of any set of reactions equal to the specific reaction. This means that if you have the enthalpies for reactions that can be added together to make another reaction, you can add the enthalpies together to find the net en...

ConnorThomas2E

I think that he will give you a problem and based on the information he gives you, you will have to use a certain method to find the enthalpy. So I would make sure to know the various methods to calculate the enthalpy.

ConnorThomas2E

As other people explained, the plateaus occur because energy is needed to break the bonds between the atoms in order for a phase change to occur. The molecules absorb the heat, even though the temperature is not increasing. This is the reason that steam burns are worse than boiling water burns.

ConnorThomas2E

Compressing a system will decrease the volume, which will increase the pressure. For equilibriums, when the pressure is increased, the equilibrium will shift towards the side with less moles of gas.

ConnorThomas2E

I think you have to know the whole name incase the test gives you the formula of a complex and you have to name the whole complex. I think you only use the abbreviation when writing the formula, not the full name.

ConnorThomas2E

Protonation is when a base receives a proton. Deprotonation is when an acid donates a proton.

ConnorThomas2E

The conjugate seesaw is where if you have a strong base, its conjugate will be a weak acid or if you have a strong acid, its conjugate base will be a weak base. It works the opposite way too, where weak acids will have stronger conjugate bases and weak bases will have stronger conjugate acids.

ConnorThomas2E

I don't think you do. All you have to do is show what the central atom is and which atom is bonding with the central atom.

ConnorThomas2E

With just Kc, you can only determine if the reaction favors the products or reactants. You need to find Q in order to see which direction the reaction will shift.

ConnorThomas2E

For bond notation, you first list the time of bond (pi or sigma), then you list one of the atoms and which orbital the electron is coming from (hybrid, p, or s), and then you list the second atom and which orbital the electron is coming from. For example, if you have an atom such as H2CO, the notati...

ConnorThomas2E

I believe so. I don't think you can use hybrid orbitals for pi bonds, and it would therefore have to come from the p orbital.

ConnorThomas2E

pH decreases as temperature increases. This is because at higher temperatures, ionization increases. This means water will dissociate more and form more H+ ions.

ConnorThomas2E

In module 4, the question asks: The photosynthesis reaction, 6 CO2(g) + 6 H2O(l) ⇌ C6H12O6(aq) + 6 O2(g), is endothermic. What effect will the following changes have on the equilibrium composition. a) Water is added. b) The partial pressure of CO2 is decreased. The answer was a) Increase [C6H12O6] a...

ConnorThomas2E

I think you got all the shapes we learned.
The formula for seesaw is AX4E and the formula for T-shaped is AX3E2

ConnorThomas2E

The weaker the bond strength of an Acid, the stronger it will be because it will be able to dissociate quickly and therefore create more H30. When measuring pH, since it is weaker and more easily dissociated, there will be a higher molarity in H+ ions and the pH will show that it is a stronger acid.

ConnorThomas2E

When I do these problems, I like to think of heat as one of the reactants or products. For an endothermic reaction, I think of the energy as a reactant because the reaction requires energy, and when a reaction is exothermic, I think of the energy as a product because it releases energy. With this in...

ConnorThomas2E

I believe it is because the triple bond in Benzyne results in a linear shape for that carbon, which in turn makes it highly reactive because the molecule typically is not linear. The triple bond will break because of this and form a double bond with a more stable shape.

ConnorThomas2E

The goal is to create a molecule with overall lower energy. Although it takes energy to bring an electron from the s sub shell to the hybrid orbital, the molecule that forms bonds will typically have a lower overall energy because of how hybridization allows for more bonds to form.

ConnorThomas2E

I believe that this is just one of the resonance structures, and typically the Lewis structure for iodate has iodine double bonded to 2 of the oxygens and single bonded to a third with a lone electron pair.

ConnorThomas2E

I’ve noticed that typically elements form a maximum of six bonds when they have an expanded octet. However, I’m not sure if this is the maximum or just what is common.

ConnorThomas2E

The bond order is determined by the number of valence electrons between the atoms as well as the formal charge. This will help you determine whether you need to form a single, double, or triple bond. The bond order is then just 1,2 or 3 corresponding to single, double, and triple bond.

ConnorThomas2E

The best way to tell is that the electro negativity is <1.5 for covalent bonds and is >2 for ionic bonds. It is also important to realize that some ionic bonds have covalent bond characteristics, and some covalent bonds have ionic bond characteristics. This depends on the extent of attraction of an ...

ConnorThomas2E

I also have a follow up question to this. Is there a way to tell which of the electron configurations in groups 6 and 11 will be exceptions? and why are some exceptions but others not?

ConnorThomas2E

When you write an Electron configuration that is abbreviated, such as the electron configuration for Magnesium which is [Ne] 3s2, can you use can element for the abbreviation or does it have to be a noble gas? For example, could I use Beryllium when writing the electron configuration for Magnesium s...

ConnorThomas2E

Typically, I use the more precise number because I try to limit the possible rounding errors that could affect my answer. I also try doing this by keeping the whole numbers in my calculator and try as little to possible to round until I get my final answer. However, as other people are saying, there...

ConnorThomas2E

ΔE is the change in energy and can have either a positive or negative value. You usually use the equation when an electron absorbs energy to move to a different energy level.
E is the energy of a given wavelength. It typically shows you how much energy a photon has.

ConnorThomas2E

For this problem you first determine the concentration of the NH4NO3 with it's new volume: .20M(1.0L) = .20mol .20mol/(3.0L+1.0L) = .05M After finding the concentration of the solution, it doesn't matter how many plants there are. It is asking how many moles one of the plants receives, so you just n...

ConnorThomas2E

What are the differences between the Molecular and Empirical formulas? More specifically, how do you identify one from the other? I have a similar additional question to add to this post. When doing a problem, what is the best way to realize if I have found the molecular or empirical formula? Somet...

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