CHEMISTRY COMMUNITY

YashDeshmukh1D

Can someone explain the concept of kinetic control? I understand that thermal control is a reaction that is dependent on the temperature that it occurs, but how would you be able to differentiate between the two by looking at a phase diagram?

YashDeshmukh1D

In terms of the complexity of molecules, would a more complex molecule (with more electrons) have higher entropy than a number of smaller molecules (who, in their more numerous state, have more possible arrangements)?

YashDeshmukh1D

I was confused about this too. If all containers have 1 mol of gases, there would be 6.22x20^23 molecules in each container, regardless if they are monatomic or diatomic. However, since each diatomic molecule can have two distinct orientations while the monatomic can only have one, shouldn't the dia...

YashDeshmukh1D

S as described by the Boltzmann equation describes positional entropy. That is, the total entropy or disorder as a result of the orientations of the molecules, rather than their thermal entropy, which is determined by their motion. Delta S usually combines both these quantities to describe how entro...

YashDeshmukh1D

I would say to do it just to be safe. Technically phases are supposed to be part of every reaction, although they are more important in some cases (like when calculating Q) than others.

YashDeshmukh1D

Intermediates are produced by one of the reaction steps, meaning it first appears as a product. It then acts as a reactant in subsequent steps, ensuring that it is cancelled out in the overall reaction.

YashDeshmukh1D

From what I understand H+ and OH- ions are included in the diagram, but their product (H2O) is not included since the reactions occur in aqueous conditions and water is the solute.

YashDeshmukh1D

Cell diagrams are written in the order of electron flow. By that logic, the order of species should always go from oxidized to reduced, regardless of which side the electrodes are on in the drawing.

YashDeshmukh1D

With this question, since both beakers will have aqueous solutions, wouldn't the chrome conductor be required in both beakers? How would you construct the cell with just a single chrome piece?

YashDeshmukh1D

I think for the most part the question will tell you which one is used. Overall, if the question asks what its function is, both essentially perform the same functions by allowing for the movements of solutes to prevent charge buildup.

YashDeshmukh1D

Porous disks also perform the same role as salt bridges by allowing solutes to recycle back and prevent charge from building up.

YashDeshmukh1D

I was confused about this too?

YashDeshmukh1D

Both catalysts and intermediates get cancelled out during the elementary steps of a reaction and do not appear in the overall reaction equation. Catalysts speed up the reaction by providing an alternate pathway (or reaction mechanism) with a lower activation energy, allowing the reaction to proceed ...

YashDeshmukh1D

Collision theory essentially states that molecules (usually in a gaseous phase) will bond if the three requirements are satisfied: 1) whether the molecules are of the right size and traveling at the right speed (this is affected by temperature) 2) whether they have greater than the minimum energy to...

YashDeshmukh1D

When given the elementary steps of a reaction, both intermediates and catalysts are cancelled out when writing the overall reaction. In problems like 15.71, how can you tell if a cancelled out species is an intermediate or a catalyst?

YashDeshmukh1D

Wait I thought catalysts could appear in the rate law if they are part of the slow step that determines the overall rate law? I think pages 651 and 652 of the textbook mention this.

YashDeshmukh1D

Helen Shi 1J wrote:When would you use the equation with E=E-RT/NF lnQ vs E=E-.05916V/N logQ?

These are the same equation. 0.05916 is the value of (RT/F) at 298.15 K with ln converted to log.

YashDeshmukh1D

Converting H+ to H2 is reduction, since the charge of the H goes from +1 to 0. Cathodes undergo reduction, which would mean that this half reaction should be placed on the right side of the salt bridge of the cell diagram. Converting H2 to H+ is oxidation, since the charge of the H goes from 0 to +1...

YashDeshmukh1D

Cell diagrams are written in the order in which the electrons flow. This means that the reduction half reaction (or the cathode) will be on the right side of the diagram while the oxidation half reaction (or the anode) will be on the right. If Fe3+ is being reduced, it will be written before Fe2+. I...

YashDeshmukh1D

When temperature is changing and volume is constant (isochoric), you use Cv. When temperature is changing and pressure is constant (isobaric), you use Cp.

YashDeshmukh1D

In reversible processes, the entropy change for the system is the opposite of the entropy change for the surroundings. This means that the total entropy change will be 0. However, this does not mean dG for reversible expansion is always 0. dG = dH - TdS, so if the enthalpy change is negative enough ...

YashDeshmukh1D

The book defines spontaneous change as "change that has a tendency to occur without being driven by an external influence." Essentially a spontaneous reaction doesn't require an additional input of energy to occur. It's important to remember that just because it is spontaneous doesn't mean...

YashDeshmukh1D

For the example you gave, we are calculating change in temperature with constant pressure, since the volume is also changing, right? So then why would you use Cv,m instead of Cp,m?

YashDeshmukh1D

I'm not completely clear on when to use which constant to calculate entropy change. Does it matter whether you're calculating entropy due to a change in volume vs. temperature vs. pressure?

YashDeshmukh1D

In Example 9.6 in the textbook, it uses the given heat capacity when measuring the entropy change from heating the liquid. However, when calculating entropy change for cooling the vapor back down, it uses Cp,m, which multiplies the given heat capacity by 4. When do you use each one?

YashDeshmukh1D

This formula is essentially a derivation of the original formula deltaH=q+w. By plugging in deltaU and PdeltaV, it is possible to achive the given formula.

YashDeshmukh1D

What are the concepts behind the heat capacities of gas ratios (monatomic, linear, nonlinear molecules)? Why do they have different ratios based on their atomic structures?

YashDeshmukh1D

When using Hess's law to find the enthalpy of formation for a compound, is it necessary for all the other reactants and products to have the same coefficients as the original equation? Also, can the final equations have fractions as coefficients?

YashDeshmukh1D

Since some transition metals can vary in charge, how do you determine what Roman numeral to place after the transition metal?

YashDeshmukh1D

What does favoring one side of the reaction mean? Can a reaction at equilibrium favor a certain side?

YashDeshmukh1D

Trigonal bipyramidal is just the ideal structure when there are 5 regions of electron density. Which atoms compose those regions does not matter as much.

YashDeshmukh1D

Why can atoms in sigma bonds rotate, but those in pi bonds unable to do so? Why does the cylindrical region of electron density only form in sigma bonds but not in pi bonds?

YashDeshmukh1D

If molecules take on bent shapes as a result of the lone pair electrons taking up far more space than the bond pair electrons, why are the lone pairs directly adjacent to one another? In the case of H20 for example, wouldn't O's lone pairs be on either side of the atom, resulting in an overall linea...

YashDeshmukh1D

Can a molecule have all polar bonds but still not be a polar molecule due to the symmetry of its structure?

YashDeshmukh1D

What does the textbook mean when it describes resonance structures as having the average bond from among all its possible variants?
How is it possible to have 1.5 bonds as compared to a single or double bond?

YashDeshmukh1D

How does the final atom just relinquish its lone pair electrons like that, especially if it does nothing to fulfill its own octet? Does the electronegativity of the central atom have to be significantly high for that attraction to occur?

YashDeshmukh1D

If we can understand that going across a period from left to right results in an increase of nuclear attraction (since no energy levels are being added to offset the increased number of protons) and that going down a group results in a decrease of nuclear attraction (since the increased energy level...

YashDeshmukh1D

How are the lobes of the p orbitals oriented around the axis? Are they "straddling" the axes or are they on opposite sides of each plane?

YashDeshmukh1D

Is it possible to calculate the number of photons in a beam of light of a specified amount of energy?

YashDeshmukh1D

Does this mean that even large objects like cars and balls still demonstrate wavelike behavior even though we can't visibly detect it?

YashDeshmukh1D

Does de Broglie's equation apply to particles of matter as well as photons of electromagnetic radiation?

YashDeshmukh1D

How exactly does Planck's hypothesis solve the ultraviolet catastrophe? Even if bodies require a minimum threshold of energy to emit certain frequencies (quantum theory), why would that imply a maximum limit that stops bodies from emitting high energy radiation that "lays waste to the countrysi...

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