CHEMISTRY COMMUNITY

Charles Gu 1D

The Arrhenius equation is usually k=Ae^(-Ea/RT). If you ln both sides you would get lnk=lnA- Ea/RT. This allows you to figure out the graph since it is in y=mx+b form. 1/T would be the x axis, lnk would be the y axis, and m would be -Ea/R. Therefore, it would be a straight line with a negative slope.

Charles Gu 1D

The Arrhenius equation is usually k=Ae^(-Ea/RT). If you ln both sides you would get lnk=lnA- Ea/RT. This allows you to get a better view of the graph since it is in y=mx+b form. 1/T would be the x axis, lnk would be the y axis, and m would be -Ea/R.

Charles Gu 1D

If you are referring to Lyndon's packet, he is referring to the number of molecules that need to collide at a certain orientation and activation energy based on the order of the reaction. If the reaction was 3rd order then that would mean 3 molecules would have to collide in a certain orientation an...

Charles Gu 1D

It's possible if 2 of the reactants are in zero order and one of them is in first order.

Charles Gu 1D

The final will be cumulative and cover everything from weeks 1-10.

Charles Gu 1D

The overall order of the reaction can be found by adding all of the exponential factors of each reactant. For example, if Rate=k[H][C], then it would be a second order reaction since each reactant only has a 1 in their exponent

Charles Gu 1D

E˚ is under standard conditions such as 1 atm and 298 K while E is under any other condition.

Charles Gu 1D

PV=NRT is a very versatile equation. You can use it for questions that want you to find a missing variable in the equation after plugging everything in.

Charles Gu 1D

Delta G can be found in many ways. Its just depends on what the question gives you. For example if it gave the delta H, delta S, and Temperature, you would use Delta G= DeltaH- TDeltaS

Charles Gu 1D

Elements in their natural state have 0 Gibbs free energy.

Charles Gu 1D

Yes, due to your Discussion section. Same as always

Charles Gu 1D

He said that it's better to do it the other way since it provides a better understanding of what's going on. Also, it's less confusing.

Charles Gu 1D

Entropy units are usually J/k

Charles Gu 1D

you would need to add the phase change and then the how much entropy it took to raise the temperature. so Delta s = q/t + Delta s= nCln(T2/T1). Don't forget to change temperature to kelvin.

Charles Gu 1D

A positive delta H is for endothermic reactions which will absorb heat and also increase entropy. A negative Delta h is for exothermic reactions which will entropy to decrease since heat is released

Charles Gu 1D

An isolated system does not allow matter or energy to be exchanged so it will be at equilibrium.

Charles Gu 1D

Closed systems allow energy to be exchanged with the surroundings. A thermos, therefore, keeps the liquid inside from interacting with its surroundings and does not allow matter to escape either so it is isolated.

Charles Gu 1D

I recommend doing all the homework problems, review the problems that your TA went over, and go over your notes. Also, review session are an amazing way of covering all topics in a short period of time.

Charles Gu 1D

In order to break bonds, you need a input of heat so thats why delta h is positive (endothermic)

Charles Gu 1D

Enthalpy, Volume, Temperature, Pressure are all state properties since it doesn't matter how the substance was prepared while extensive properties focus on how much matter there is

Charles Gu 1D

Surroundings can be broad as the universe or limited to a container

Charles Gu 1D

Decreasing volume means an increase in pressure which would shift to the side with less moles of gas.

Charles Gu 1D

Just look at gases when dealing with pressure.

Charles Gu 1D

The quadratic formula will also be given.

Charles Gu 1D

If an acid is strong, the conjugate base will be weak and vice versa.

Charles Gu 1D

Since solids and liquids concentrations will not change, they will be eventually canceled out. Therefore, they are not included.

Charles Gu 1D

If Q, the reaction quotient, is greater than K, then the reaction will favor the reactants but if Q is smaller than K than the reaction will favor the products

Charles Gu 1D

The units cancel out

Charles Gu 1D

Dr. Lavelle has not covered thermodynamics yet so right now just focus on equilibrium

Charles Gu 1D

yes you can assume that

Charles Gu 1D

If there are multiple polydentates, make sure to use bis(2), tris(3), etc.

Charles Gu 1D

The best way to memorize them is to just do practice problems and you will start getting used to eat transition metal.

Charles Gu 1D

During my Discussion, my TA (Ben) said that either would be acceptable.

Charles Gu 1D

You have the to know the oxidation numbers of most of the molecule and match the total charge of the molecule in the end.

Charles Gu 1D

In order to find oxidation numbers you have know the oxidation numbers of at least most of the molecule and then match the charge of the molecule.

Charles Gu 1D

You should probably be familiar with both for the final. I'm not too sure what it would entail, but try practicing both

Charles Gu 1D

A little bit from outline 3, but all of outline 4 so make sure to study them.

Charles Gu 1D

The orientation of a shape doesn't really matter on the test since Professor Lavelle doesn't expect us to draw the shape. He only wants to know the Lewis structures of molecules and find the shape from that.

Charles Gu 1D

Professor Lavelle said we only need to draw the lewis structures and identify the shape. We would never need to draw the shape;

Charles Gu 1D

You just need to memorize them. There are a lot of good practice problems that help you memorize the angles in the book.

Charles Gu 1D

You should memorize it. Doing the practice problems in the book will help you memorize them.

Charles Gu 1D

You should draw the lewis structures to get a better understanding of what you are looking for.

Charles Gu 1D

No you don't need to write formal charges, but it'll help you determine whether or not there is a resonance of a more stable structure.

Charles Gu 1D

We haven't learned the structures yet, but placement will matter soon.

Charles Gu 1D

Ionic bonds have oppositely charged ions that create a coulombic attraction while covalent bonds only share electrons

Charles Gu 1D

Each atom has its own formal charge. You will need to to check the formal charge of each of them in order to find the stability of the whole molecule.

Charles Gu 1D

A double bond is stronger than a single bond but single bonds are longer than double bonds.

Charles Gu 1D

Since there are fewer electrons in the outer shell, each electron has a stronger attractive force. This causes it to be harder to remove.

Charles Gu 1D

Test 2 will only go up to what was covered on last Friday which was the quantum numbers.

Charles Gu 1D

Delta X is usually the diameter in meters. If it is given in radius you should use that in meters.

Charles Gu 1D

Sulfur has less ionization energy than oxygen since its valence electrons are at a higher orbital and since the distance is farther, it would be easier to remove an electron due to shielding.

Charles Gu 1D

You have to multiply it by Avogadro's number which is 6.022 x 10^23. This will give you the number of photons

Charles Gu 1D

Thank you! I was always confused with the order of the equation.

Charles Gu 1D

Everything that is listed for Quantum World on the syllabus will be tested.

Charles Gu 1D

You will get better throughout the year as you do more problems, so need to stress about it too much. You always can search up common ions to memorize if you are feeling worried.

Charles Gu 1D

You first have to use the M1V1= M2V2 equation in order to get M2. After calculating for M2 (Molarity of NH4NO3), multiply that by 0.1 L (100 ml, given in the problem) in order to get the moles of NH4NO3. Since there are 2 moles of N for every 1 mol of NH4NO3, multiply the mols of NH4NO3 by 2 and you...

Charles Gu 1D

Don't forget about the modules on Professor Lavelle's website. Also, my TA said the test will be around 8 questions with subsections.

Charles Gu 1D

I think you should maintain your rounding to the lowest number of sig figs that is given in the problem. For example, if the problem says there are 5.43 grams of Carbon and that is the lowest number of sig figs given in the problem, then your calculations should have 3 sig figs too.

Charles Gu 1D

You should probably round off to the lowest number sig figs that is given in the problem. So if the problem says that there is 4.56 grams of carbon, you should round off to 3 sig figs.

Charles Gu 1D

You probably should make an educated guess so that if you are wrong you can learn from your mistakes. Someone asked today in class if we needed to memorize the states of molecules and Dr. Lavelle said that as the year goes on, we will be more familiar with them.

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