CHEMISTRY COMMUNITY

Laila Sathe 1D

No, when naming a cyclic molecule you only use cis/trans or E/Z when there are 2 substituents.

Laila Sathe 1D

What happens if the numbering would be equivalent either way?

Laila Sathe 1D

In the examples in the course reader, there's one on page 96 that has the substituent "ethoxy" on a parent chain. How do you know to name the substituent this?

Laila Sathe 1D

do you know what lavelle's policy is with temperature sig figs? a ta mentioned that we should ignore sig figs in temperature.

Laila Sathe 1D

Einstein, Pascal, and Newton are playing hide and seek. Einstein is counting while Newton and Pascal hide. Pascal runs off and hides while Newton doesn’t move an inch. Instead, he draws a square around himself in the dirt. After Einstein finishes counting, he opens his eyes and says, “Found you Newt...

Laila Sathe 1D

Look at the units of the constants given (initial concentration and k) and the units that should be in your answer.

You should multiply 3 quantities to get your answer.

Laila Sathe 1D

How do you know what reaction takes place between the O₂ and H⁺? I understand that they react because they are on the same side of the double line in the cell diagram, but I don't get how you figure out what reaction takes place.

Laila Sathe 1D

How do you know oxygen is being reduced? It goes from a neutral triatomic molecule to a neutral diatomic molecule. Does the oxidation state change in the reaction of O₃-->O₂?

Laila Sathe 1D

I think the question will indicate that.

Laila Sathe 1D

Work is negative relative to the system when the system expands because the system loses energy as it does work on the surroundings. It's positive when the system is compressed because the surroundings do work on the system. Because, in this case, delta V is negative, the value for work will be posi...

Laila Sathe 1D

Yes, there is. In fact, the work done by the system on the surroundings is maximized in a reversible system.

Laila Sathe 1D

Temp does not increase because the energy being added to the system is being used to break bonds and change the phase of matter instead of increasing the temperature. During the period of ice melting/freezing at 0 o C, the substance is actually a combination of water and ice, and energy is being add...

Laila Sathe 1D

When you add a strong base, like NaOH, to a solution it will dissociate fully, meaning it will completely ionize into Na + and OH - ions. Thus, the H + ions from the dissociation of the weak acid (HA) will bond with the hydroxide ions to form water. More because A - and H + are both on the same side...

Laila Sathe 1D

The buffer region ends when the pH starts to change significantly.

Laila Sathe 1D

Q and K represent the same kind of value, but they're used at different times. K is the equilibrium constant, meaning it represents the ratio of products to reactants at equilibrium . Q is the reaction quotient, meaning it represents the ratio of products to reactants at some other point , not neces...

Laila Sathe 1D

You can do it when it isn't obvious which direction the reaction will go. You push the reaction all the way to one side so you know what will be produced and consumed. You could also calculate Q to figure that out.

Laila Sathe 1D

I think there is, but for the purposes of this class we don't have to know that.

Laila Sathe 1D

It's an ion, which means its charged. If it was Cl₃, it would be trichloro instead of chloro

Laila Sathe 1D

Actually, adding inert gasses has no effect on the equilibrium. As Dr. Lavelle mentioned, changing pressure changes concentrations and concentrations are then what affects the equilibrium position. When you add an inert gas, there is NO change to the concentrations of reactants (total volume and mol...

Laila Sathe 1D

There is a formula... I would imagine Dr. Lavelle will teach it but he hasn't yet. It's derived from the Ideal Gas Law: K p =K c (RT) delta n This website may help: http://chemwiki.ucdavis.edu/Physical_Chemistry/Equilibria/Chemical_Equilibria/The_Equilibrium_Constant/Calculating_An_Equilibrium_Conce...

Laila Sathe 1D

Think of just one pyramid with a square bottom. The atoms on each corner of the bottom of that pyramid will be 120 o away from one another. The atom at the top point of that pyramid will be 90 o away from the other atoms because it's in an orthogonal plane. When you add another atom on the opposite ...

Laila Sathe 1D

You're right, in a square pyramidal structure the bond angles are slightly less than 90 degrees according to VSEPR theory. And yes we do have to know about molecules in that form, which have the shorthand abbreviation AX₅E.

Laila Sathe 1D

I was wondering this too and I found this: http://www.madsci.org/posts/archives/20"onclick="window.open(this.href);return false; ... .Ch.r.html Basically it's an exception to the exception. But Dr. Lavelle said we don't have to know any exceptions other than chromium and copper, so don't worry about...

Laila Sathe 1D

It's because copper is one of the exceptions to regular orbital filling rules: copper's electrons completely fill the 3d orbital and leave the 4s orbital with only one electron. Because the 4s orbital is a lower energy orbital than the 3d orbitals, the valence electron that is lost when Cu ionizes t...

Laila Sathe 1D

Hund's rule basically says that due to the repulsive forces between electrons, electrons fill orbitals within a subshell in a specific way: they fill first all available orbitals in that subshell with just one electron, each with parallel spins. Then, only once each available orbital has one electro...

Laila Sathe 1D

Yes, this has to deal with the concept of shielding. Electrons closer to the nucleus of the atom "shield" those that are farther away; the inner electrons' e-e repulsions with those that are farther away decrease the attractive force between the nucleus and those farther electrons.

Laila Sathe 1D

How do you calculate the theoretical and percent yield in this problem?

CHEMISTRY COMMUNITY

Search found 27 matches

Re: Naming with cis/trans

Re: Alkene and Alkyne

"Ethoxy" substituent

Re: Sig figs

Re: Chemistry Jokes

Re: concentration of first-order integrated rate law

Re: Question 14.11 (d)

Re: Balancing Basic Redox Reactions (HW 14.5 A)

Re: Basic or acid solution?

Re: Work of Expansion

Re: Reversible Systems

Re: Temperature Changes during Phase Changes

Re: Solving Buffers

Re: Buffer Region on a pH Curve

Re: Q vs. K

Re: ICE Chart Original Value Change

Re: Endo vs. Exothermic

Re: pentaaquachloroiron(III)

Re: Conditions favoring production - pressure

Re: Relationship between Kc and Kp?

Re: Trigonal Bipyramid Bond Angles

Re: Square Planar Angles

Re: Electron Configuration for Tungsten (W)

Re: Electron Configuration for Copper

Re: Hunds Rule

Re: Degeneracy and Energy Levels

Re: Find purity using percentage composition and yield