CHEMISTRY COMMUNITY

Lauren Su 2B

You want the electrons to cancel out, so yes you do want to reverse one of the equations (you would reverse the second equation to get a positive E value). And yes, it will E standard will change signs when you reverse the reactions.

Lauren Su 2B

So for determining priority, you would compare the atomic number of the atom attached to each carbon on the same side. But how would you determine priority if both groups attached to one carbon is the same (for example, if both of the atoms attached to one carbon is chlorine)?

Lauren Su 2B

Yes, the dash is always between the name and number! Also there is also a dash between two substituents when naming the molecule.

Lauren Su 2B

Yes, and the straight line needs to be a positive slope because in a graph of a second order reaction, the slope = k and k is always positive.

Lauren Su 2B

You can determine the units of k once you figure out the order of the reaction. The rate of the reaction will always be mol/L x s. So for a zero order reaction, the units for k will need to be mol/L x s because the reactant (which units is mol/L) will have an exponent of zero, and the reaction rate ...

Lauren Su 2B

Both methods should work. Since the given information is actually in grams, it would be easier to use specific heat capacity. Maybe they just used moles so that the numbers being calculated are smaller?

Lauren Su 2B

Yes, since the inert conductor is used to transfer electrons, you would put that after the "|" symbol at the end of the cell diagram. The inert conductor is the "interface between phases" described in the lecture notes.

Lauren Su 2B

The first is -40.0 KJ because for the first reservoir energy is released. The energy is then absorbed by the second reservoir (at 200. K), which is why it is written as +40.0 KJ. In order to find the total change in entropy, you add the two changes in entropy together.

Lauren Su 2B

Yes, the reaction would be the system and the calorimeter would be the surroundings. The reaction releases energy in the form of heat that will be absorbed by the calorimeter (in other words, the reaction loses energy while the calorimeter gains it), which is why there is a negative sign for q(react...

Lauren Su 2B

Based off of what I found, a refrigerator has two main components: the evaporator coil and condenser coil. The condenser coil is outside the fridge and the evaporator coil is inside the fridge cabin. It also has a compressor, which uses electricity to compress a gaseous form of a refrigerant/coolant...

Lauren Su 2B

You should be able to find Ka1 and Ka2 from Table 12.10 in the textbook. I think you're supposed to look at both K values unless Ka2 is so small that it would be insignificant to the resulting pH of the solution.

Lauren Su 2B

For the midterm, I only mentioned that there were 3 lone pairs in XeF2 but I didn't explain the role lone pairs played in the shape, so I missed a point. I think you should mention VSEPR for both molecules and also mention the fact that for XeF2 the lone pairs have strong electron repulsions that pu...

Lauren Su 2B

Not necessarily, especially because after the first proton is removed the K value for the second reaction is always smaller than the first. This is because the anion has a stronger pull on the proton. So for a certain acid, if the K value is smaller than the K value for another acid--even if this ac...

Lauren Su 2B

I think you can do it when it is a quantity + x, but usually it is the products that have a quantity + x in an equilibrium equation, and you'll need to keep the x there so that you can solve for its value.

Lauren Su 2B

The equilibrium constant is calculated using the concentrations of the reactants and the products. So if a substance is a gas occupying a space, or if a substance is dissolved in a solvent, it has a concentration. However, liquids and solids do not have a "concentration" exactly, so they a...

Lauren Su 2B

Bond order actually refers to the number of bonds between atoms, so the higher the bond order the higher the number of chemical bonds (and thus the molecule is more stable). A bond order less than one usually just means that the molecule isn't very stable and is unlikely to form that molecule.

Lauren Su 2B

Not really, it's just that usually molecules with 5 regions of electron density (trigonal bipyramidal shape) are drawn that way. XeF2 has the same number of regions of electron density, but it has 3 lone pairs. So the result is a bond angle of around 180 degrees.

Lauren Su 2B

First, you count the number of valence electrons for each of the elements. Usually when you make your Lewis structure and there aren't enough electrons to make an octet for every element, then you know you need to add a double bond. You can also use formal charges to figure out whether or not to add...

Lauren Su 2B

Does anyone know what electrostatic (coulomb) potential energy means? I'm still a bit confused about that...

Lauren Su 2B

Also, since the Hamiltonian is the second derivative, I think it's used to show the change in the wave function, aka the orbital.

CHEMISTRY COMMUNITY

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Re: Making a battery

Priority Groups

Re: How do we know where to put the dashes?

Re: Differentiating between graphs

Re: units of k

Re: When to use molar heat capacity vs specific heat capacit

Re: Cell Diagram question

Re: total entropy change

Re: 8.25

Re: Open, Closed, and Isolated Systems

Re: Question 12.81

Re: Midterm Question #4.B: Explaining molecule's shape

Re: polyprotic acids

Re: setting x= very close to 0

Re: Liquids and Solids in Chemical Equilibrium

Re: Bond Order

Re: Lewis Structure XeF_2

Re: Triple or Double Bonds

Electrostatic Potential Energy

Re: What is the hamiltonian?