CHEMISTRY COMMUNITY

Cooper Baddley 1F

Just because the speed of the reaction is different doesn't mean the reaction itself is. It will still have the same enthalpy value.

Cooper Baddley 1F

Any resource should be up for use except for chemistry community just because he said we can use it up to the day of the final.

Cooper Baddley 1F

In the scope of this class, you should not need to know to find pKb for pOH

Cooper Baddley 1F

You don't need to know steady state for this class

Cooper Baddley 1F

My hope is we will do the work ourselves and then submit it as a PDF electronically so it can be graded for partial credit.

Cooper Baddley 1F

Hard to say something is always spontaneous but most of the time it will be

Cooper Baddley 1F

Use the oxidation numbers to determine which is oxidized and reduced. Then whatever one is oxidized is the reducing agent and the one being reduced is the oxidizing agent.

Cooper Baddley 1F

The Mn is actually being reduced because it is going from a charge of +7 to +2 so that would be your cathode.

Cooper Baddley 1F

You set up the concentration cell and then use the Nernst equation to solve for potential.

Cooper Baddley 1F

Water first for the oxygens and then the H+ for the hydrogen difference.

Cooper Baddley 1F

First, you start with just the oxidation of the reduction reaction with nothing else. You balance the things that are not oxygens or hydrogens first with a coefficient. Then you balance the oxygens by adding water to whatever side that needs it (Only worry about the oxygens at this point). Then you ...

Cooper Baddley 1F

It's better to keep oxidation on the left and reduction on the right for cell diagrams or not. It says so in the textbook

Cooper Baddley 1F

Rest of outline 4 and outline 5

Cooper Baddley 1F

The only difference is acidic solutions you at H+ with the waters and for basic solutions, you add OH-

Cooper Baddley 1F

The thing that takes the electrons is being reduced while at the same time it is oxidizing the other compound to get those electrons. Then the other situation is true, the thing that loses the electrons is being oxidized but also it is in a way giving those electrons to another compound which then r...

Cooper Baddley 1F

Break the molecule into each of its elements. Then use a periodic table to find the normal charge of each element. Then combine those to find the oxidation number.

Cooper Baddley 1F

The Pt is more of a bridge for the electron that allows it to get from one side to the other so it can reduce.

Cooper Baddley 1F

Standard points are your references that you would use if specified. Otherwise you will use the non standard value in a problem.

Cooper Baddley 1F

Anything standard is just that variable at standard conditions

Cooper Baddley 1F

Positive E means negative Delta G

Cooper Baddley 1F

The systems we deal with now only have work when they expand or get compressed.

Cooper Baddley 1F

The Cis has more because each atom can be present in each plane while the trans structure only allows a certain atom in each plane which restricts the possible states.

Cooper Baddley 1F

The formula for the phase change is Energy = mass*entalpy of fusion. You are given that half of the original 125g melts so you have 62.5g and then that the total energy is 234 KJ. Plug those in and solve for enthalpy of fusion.

Cooper Baddley 1F

State functions means that the path doesn't matter so it is the same.

Cooper Baddley 1F

ShastaB4C wrote:What did I do wrong? The answer is supposed to be 16 degrees Celsius

The ice goes through a phase change so you need to add that heat to the equation on the side of the ice.

Cooper Baddley 1F

It's flat when the energy in changes from being used to heat the substance to changing the phase of the substance

Cooper Baddley 1F

In a reversible reaction, the countless amount of small movements lead to more work being done when compared to an irreversible reaction where one big action is done causing there to be less overall work

Cooper Baddley 1F

A combustion reaction always consist of the hydrocarbon plus O2 equaling CO2 plus H20 and in some cases nitrogen gas as well if it was present in the hydrocarbon

Cooper Baddley 1F

Energy is never destroyed in an isolated system just changes form. So the energy you begin with will be there in the end in some form or another.

Cooper Baddley 1F

In a problem, the big difference you need to spot is if the system is pushing against constant pressure or not. If it is it's irreversible but if the pressure changes its reversible.

Cooper Baddley 1F

Ideal gas law but make sure you use the value of R that allows you to cancel your units correctly.

Cooper Baddley 1F

He has never mentioned extra credit so I wouldn't get your hopes up.

Cooper Baddley 1F

The midterm will cover everything before it. Test 2 will cover everything after the midterm to the test and then the final covers it all.

Cooper Baddley 1F

He post everything to the class website

Cooper Baddley 1F

Both should be ok just stay close to the lectures.

Cooper Baddley 1F

Outlines 1 and 2 are very important and make sure to know the relation between pH and concentration.

Cooper Baddley 1F

The final in particular features overall concepts not just problems so while the test is pretty straight forward in their content the final is much more tricky.

Cooper Baddley 1F

There are 1000 little calories in 1 Calorie. We use Calories when it comes to diet and calories when it comes to heat and energy.

Cooper Baddley 1F

Exothermic means it releases heat so yes it will mean the temperature of the system decreases

Cooper Baddley 1F

If the K value is less than 10^-3 and then if the percent protonation is less than 5% it is ok to take the shortcut.

Cooper Baddley 1F

Always leave out the solids and bases they will not be changed enough to be included.

Cooper Baddley 1F

Ice tables seem to be useful only when it comes to calculating the number of products and reactants are present at equilibrium for a reaction.

Cooper Baddley 1F

When referring to acids and bases protonation is gaining a proton so this usually refers to a base as they are the ones that gain an electron and deprotonation refers to the acid because they are the ones giving up a proton.

Cooper Baddley 1F

Jasmine Vallarta 2L wrote:when is test 1?

It's in your week three discussion section

Cooper Baddley 1F

You will have plenty of time on the test so you might as well.

Cooper Baddley 1F

Q is basically the same thing as K but the reaction is not at equilibrium, so yes it can.

Cooper Baddley 1F

K is the ratio of products over reactants at equilibrium, Q is the same thing not at equilibrium

Cooper Baddley 1F

K can only be taken when the reaction is at equilibrium while Q can be taken at any point and through comparing them we can see where the reaction is overall. Other than that they use the same formula and rules.

Cooper Baddley 1F

The K value gives you the ratio of the products over the reactants so it being bigger or smaller tells you about the total concentration of each side of the ratio

Cooper Baddley 1F

The reaction quotient or Q is the ratio of the products over the reactants at whatever time you calculated the concentrations at. We then compare this ratio to the known K value or equilibrium constant to see if the reaction is still going and in what direction.

Cooper Baddley 1F

The metal has the -ate ending when the compound is the anion and has an overall negative charge

Cooper Baddley 1F

I would make sure to know the chart that he has posted on the website when it comes to naming

Cooper Baddley 1F

Know the chart he posted

Cooper Baddley 1F

The questions will most likely look like the ones we had on the midterms and the two quizzes so it would be beneficial to look back over those.

Cooper Baddley 1F

I think it was more something to think about when it comes to future classes but if you want to be safe you could make sure to know the overall points he is making in case they come up

Cooper Baddley 1F

(OH2) is aqua

Cooper Baddley 1F

Pi bonds only occur as the other bonds in double and triple bonds. For example, a double has one sigma and one pi bond and a triple bond has one sigma and two pi bonds.

Cooper Baddley 1F

Ferrum refers to the latin name for iron and then the compound has an overall negative charge so you add ate to make it ferrate

Cooper Baddley 1F

I understood this question as from sp3 to sp2 the bond angles increase from 109.5 to 120 so if it goes from sp2 to sp you would expect bond angles of 180 as it would be in a linear arrangement

Cooper Baddley 1F

Dirty coal has more sulfur which then leads to acid rain vs clean coal which contains much less sulfur and contributes to acid rain less.

Cooper Baddley 1F

Both size means more electrons which means more polarizability which then leads to stronger London forces

Cooper Baddley 1F

For a hydrogen bond to occur the N, O, and F also has to have a lone pair

Cooper Baddley 1F

AX3E2 is the only formula that leads to T-shaped as trigonal bipyramidal is the only shape that has those flat 90-degree equatorial bonds.

Cooper Baddley 1F

The arrangement really doesn't matter in this case as all you would need to get from the lewis structure is that there are 4 areas of electron density around the central atom and that would make it have a tetrahedral shape and all the characteristics that come with it.

Cooper Baddley 1F

Yes, bonds are calculated with the electron pairs added in so even though there is a certain amount of density spots some are electron pairs that repel the actual bonds off of there new position.

Cooper Baddley 1F

It is T-shaped as you are having the electron pairs occupy the equatorial spots in order to reduce the effect they will have on the bonds. In doing this you are left with one equatorial and the top and bottom leading to T-shaped.

Cooper Baddley 1F

The book brings up two methods one with the arrow pointing towards the negative and the other pointing towards the positive but Lavelle always has it point towards the negative so I would do that.

Cooper Baddley 1F

If the problem says something about radiation, don't use DeBroglie as this does not have a mass, but anything else including an electron has mass and you will use this formula.

Cooper Baddley 1F

You find the moles of the whole substance they are involved in and then multiply by the total number of the element is in the compound for example if its H2O and you want to get grams of hydrogen you find the moles of H2O and then multiply by 2 because 2 hydrogens are in H2O and then multiply by the...

Cooper Baddley 1F

It seems like the only time 2Px, 2Py, 2Pz are ever important is just to understand the three shells in the p and how 6 valence electrons fit there, or to understand how the configuration is supposed to look.

Cooper Baddley 1F

The trend in the periodic table should be good enough as usually, the difference is pretty apparent and doesn't require actually knowing the values.

Cooper Baddley 1F

Midterms back after the lecture on Wednesday and I'm guessing he will put out the key on the class website for the test that night.

Cooper Baddley 1F

Lavelle has only mentioned the original convention with the arrow pointing towards the negative charge in class so I would say it's safe to stick with that one.

Cooper Baddley 1F

The value is given in normal meters/second fashion and you can convert it beyond that.

Cooper Baddley 1F

My guess is chemical bonds because it is the most recent focus we have gone through.

Cooper Baddley 1F

You don't need to use the formal charge equation for this problem just the total number of valence electrons. By finding the that that element accounts for five total valence electrons it points you to group 15 and the problem tells you it's in the third period so you go over to group 15 down to per...

Cooper Baddley 1F

I'm pretty sure he said the midterm is eight questions so my guess is that each outline is going to have 3 questions except for one and because we already had a test on the fundamentals I would think that would be the section to only have two questions, but that is all speculation.

Cooper Baddley 1F

We need to know all of outlines 1 and 2 and most of outline 3.

Cooper Baddley 1F

The number of valence electrons for an element is equal to its group number starting at one on the left and moving to eight on the far right.

Cooper Baddley 1F

It increases as you move left to right across the periodic table and up groups meaning elements such as Fluorine have very high electron affinity.

Cooper Baddley 1F

The excited state of an atom is going to be a state where the electrons are arranged in a way that is not energy efficient meaning the only way it is possible is if there is extra energy present. For example, in part A of 1E.7 this represents an excited state of carbon because the last electron shou...

Cooper Baddley 1F

I think you can because we just started chemical bonds, next homework is probably going to be the first no Quantum World assignment.

Cooper Baddley 1F

I think it comes from the element's unfilled outer orbital as it only has 5s2 and 5p3 which in total adds up to 5 valence electrons.

Cooper Baddley 1F

Finding unpaired electrons is easiest if you draw out the electron configuration first and then if done correctly the unpaired valence electrons are just the electrons don't have a pair in the configuration.

Cooper Baddley 1F

You would start in the outermost shell as well because it is easier to remove electrons from there rather than spend the energy to remove it from an orbital closer to the nucleus.

Cooper Baddley 1F

You need to change the weight from ounces to kg and the velocity from miles per hour to m/s. Then just use the de Broglie relationship lamba= h/p or h/mv.

Cooper Baddley 1F

The Aufbau principle states that you start filling the lower energy subshells before continuing on to the ones with the higher energy. So for example you wouldn't start filling up 2p before filling 2s

Cooper Baddley 1F

The different values of l indicate which orbitals the electron can be on with l=0 meaning s-orbital l=1 meaning p-orbital l=2 meaning d-orbital l=3 meaning f orbital and so on.

Cooper Baddley 1F

Just going off test 1 and how that was all calculations I feel like all the test including the midterm and final are going to be calculated based and will not feature any short answer or essay questions.

Cooper Baddley 1F

It doesn't seem like a big background in calculus is really needed for the class as all the math is usually done through plugging in values into many different equations, so as long as you understand how to work the equations and what values are what you should be fine without any additional math pr...

Cooper Baddley 1F

I like to think of them as little pieces of an overall bigger wave. It's like if you are looking at a group of birds flying the sky, you see the overall shape of them but that is made of each bird. Photons are like that as they form this overall wave but when it comes to the photoelectric test they ...

Cooper Baddley 1F

I would say to pay attention to the outlines that are on the class website when it comes to concepts you may need to know for test and then I would make sure you have an understanding on how to do all the hw problems on the syllabus especially the ones towards the end as they are usually the hardest...

Cooper Baddley 1F

The constant for speed of light as (3.00 x 10^8 m/s) refers to the fastest light can travel as it is measured in a vacuum but as stated before it can slow down when it goes through different thicker mediums.

Cooper Baddley 1F

I think it is D because of the behavior of the EMR that then leads to the emission of a particle. The idea that increasing the overall intensity of the light not leading to more electrons creates this idea that the light itself is acting as Einstein put it "packets of energy" as if it was ...

Cooper Baddley 1F

Tips that have helped me in the past: 1. Save the molecules that are just one element until the end as they are very easy to deal with due to the singular element making them very helpful when it comes to making sure the final count is balanced. 2. Try and balance the elements that only appear in th...

Cooper Baddley 1F

I wouldn't think you would lose points if you don't go out of your way to use scientific notation, but if there are some problems that ask for the answer in grams but your answer came out in kilograms it would make sense to use scientific notion to switch the units over in the clearest way. If anyth...

Cooper Baddley 1F

I don't know if different TAs have different grading policies but my TA made it sound like the HW problems are just graded quickly on a credit no credit basis because we already have the solution manual so I doubt we would get them back with any comments.

Cooper Baddley 1F

I'm pretty sure in a lecture he touched on the fact that we don't know enough yet to write out the formulas for the chemical equations ourselves so he would give us the individual compounds next to their name and then you put it together.

Cooper Baddley 1F

The email says its seven questions in 50 minutes and the first one is only on the review of high school topics. I would say the best way to prepare is just to go through all the problems on the syllabus in the first section and make sure you grasp the key concepts.

Cooper Baddley 1F

If I am doing a problem and the answer needs to have 5 Sig Figs and the answer comes out to 0.001295 would you round and put a zero after the 9 (that becomes a 0 when you round up), leave it unrounded, or round without the zero?

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