CHEMISTRY COMMUNITY

Jennifer Tuell 1B

I find using the Lewis structures helpful especially when calculating the coordination complex number and the oxidation number

Jennifer Tuell 1B

I don't think we need to know this. I would look at the outline and see if it is mentioned.

Jennifer Tuell 1B

I don't think they break because to rotate you have to break the pi bond and that takes too much energy.

Jennifer Tuell 1B

Each C will have three regions of electron density and will need three hybrid orbitals. Trigonal Planar makes each C sp2 hybridized. There will be 3 electrons in the 2sp2 region and 1 unpaired electron in 2p which is higher in energy than the hybridized region. The unhybridized 2p orbital on each C ...

Jennifer Tuell 1B

A good trick is to notice that whenever there is more than one oxygen there is probably resonance because that bond can be in different positions. Also a resonance between a single and double bond is between their lengths around 1.33 so it is longer than a double bond but shorter than a single bond.

Jennifer Tuell 1B

Cis platin forms a coordination compound with DNA when the two Cl's bind with two Guanine bases in DNA and these bases stop cells division. The CL's bind with the lone pair available on the nitrogen on the Guanine to form a cation. This makes the cis more effective than the trans because the trans h...

Jennifer Tuell 1B

Ionic Character has more to do with Electronegativity because the greater the difference in electronegativity the more similar the covalent bond is to an ionic one because the charges are distributed unevenly to a greater degree. Covalent Character has more to do with Polarizability which relates to...

Jennifer Tuell 1B

I found it helpful to read chapter 3 in the textbook. We also discussed electronegativity, polarizability, ionic and covalent character and bond strength and length.

Jennifer Tuell 1B

The ones that most likely contribute to the resonance hybrid probably exhibit about the same formal charges. Oxygen is normally a reason that a Lewis Dot structure has resonance and the structures that contribute to the hybrid are the ones that have the lowest possible charges overall. For example, ...

Jennifer Tuell 1B

I know you can just count the bonds for the bonding electrons but I find it helpful to do the 1/2 times the bonding electrons just to make sure.

Jennifer Tuell 1B

I prefer using the dots because it is helpful to calculate formal charge and keep track of valence electrons.

Jennifer Tuell 1B

The radical also normally goes on the central atom.

Jennifer Tuell 1B

I know when delta x is given as +/- 3 for example you multiply the number by 2 for the equation, but when you are given the radius of an atom do you plug in the radius or the diameter into the equation?

Jennifer Tuell 1B

Update: I forgot to add the kinetic energy to the work function before diving by h!

Jennifer Tuell 1B

I am still very confused and keep getting the wrong answer for this problem. I found v from wavelength=h/mv and then did 1/2m (mass of an electron) v^2 plus the converted work function and got 3.00x10^14

Jennifer Tuell 1B

I was confused about this too but if you think about it in terms of the lines he drew in class and how the gap gets smaller as you increase in energy level it makes sense that 4 is higher energy than 3 and 5 is higher than 4 and why when we draw electron configurations for ions we remove them from h...

Jennifer Tuell 1B

I would look on Chemistry Community because a lot of people have asked questioned about the tests.

Jennifer Tuell 1B

This is similar to how for Chromium and Copper the electron configuration is more stable for example Cr [Ar] 3d5 4s1 is more stable than
Cr [Ar] 3d4 4s2.

Jennifer Tuell 1B

I'm pretty sure this won't be on the midterm. The midterm covers Chapter 1 and 2 and the Fundamentals.

Jennifer Tuell 1B

Part C is where the question gets tricky but if you recall the equation Ephoton-Work=E excess(or kinetic energy) we know the mass of the electron and the velocity so we can find the kinetic energy and we know that it takes 1.66x10^-17 to eject the electron from the previous problem so if we rearrang...

Jennifer Tuell 1B

For part B the energy required to remove an electron is the energy of the photon E=hv plugging in v= 2.50 x 10^16 HZ and h and you get 1.66x10^-17 J

Jennifer Tuell 1B

3d is at a lower energy level than 4s therefore it comes before it in the electron configuration because it going from lowest to highest energy level.

Jennifer Tuell 1B

The test also mentioned that it was a UV light which is important to acknowledge because if it was a longer wavelength then no electrons would be ejected.

Jennifer Tuell 1B

I was also confused about this! I would argue that velocity and frequency are interchangeable especially because they have the same units.

Jennifer Tuell 1B

Sig Figs are important, but I would argue that making sure you have the right units is also important. Especially when using the speed of light and disproving certain ideas like that an electron is drawn into the nucleus, correct significant figures are essential.

Jennifer Tuell 1B

I was also confused by this question!! I'm pretty sure we were given for information than we needed in the question and some numbers didn't need to be used.

Jennifer Tuell 1B

Yeah I asked Lavelle in class if we need to know the equations and they will be provided on the exam. It would probably be helpful to memorize the units each symbol represents because it will be easier to do dimensional analysis and manipulate equations.

Jennifer Tuell 1B

You just need to manipulate the equations and its easy to see the relationship between photons and momentum especially if you do dimensional analysis.

Jennifer Tuell 1B

Does anyone have any tips and tricks for quickly balancing equations?

Jennifer Tuell 1B

The total mass of tin oxide is: 28.35g-26.45g=1.90g Then you convert grams of Sn to moles of Sn and do the same thing for oxygen to get the molar ratio: 1.50g Sn x (1 mol Sn/118.71g Sn)=1.264 x10^-2 mol Sn (1.90-1.50)g O x (1 mol O/16.00 g O)=0.025 mol O Mole Ratio of Sn:O is 1:2 so the Empirical Fo...

Jennifer Tuell 1B

I was taught to do it in one long line but it is important to write out what chemicals you are using when converting mass and moles. This is a great technique was trying to cancel things out

Jennifer Tuell 1B

In addition to units I would also add what element or molecule the value is connected to, especially when dealing with moles.

Jennifer Tuell 1B

I would also recommend making a chart. It is also important to remember that even if an equation is given to you in a problem, if there are no coefficients you need to make sure it is balanced. Even if there are coefficients it is important to double check.

Jennifer Tuell 1B

Also it is helpful to convert the moles of the given reactants to the mass of the product you are looking for the limiting reactant because you can determine the limiting reactant and find the mass in one step.

CHEMISTRY COMMUNITY

Search found 34 matches

Re: Charge of ligands

Re: Final

Re: Ligand bind to metal

Re: Hybridization and it's relation to valence electrons

Re: Test Q.8 [ENDORSED]

Re: chemotherapy example [ENDORSED]

Re: ionic and covalent character

Re: Test 3 [ENDORSED]

Re: 3.45

Re: formal charge

Re: Dots vs lines to represent electrons

Re: 3.55

Delta X

Re: 4b practice midterm

Re: 4b practice midterm

Re: 4s and 3d

Re: Solutions for tests

Re: half full?

Re: Trends to Know

Re: 1.33 using De Broglie

Re: 1.33 using De Broglie

Re: Why does the 4s orbital come before the 3d?

Re: Test 2 final question [ENDORSED]

Re: E=hv vs E=hf [ENDORSED]

Re: Use of sigfigs

Re: Test 1 Q2

Re: Tools for remembering equations

Re: still don't uderrsatnd what a photon is [ENDORSED]

Balancing Chemical Reactions

Re: Help with homework problem L.39 [ENDORSED]

Re: writing out conversions in one long line vs. steps

Re: Using units in calculations [ENDORSED]

Re: H.5: Balancing Equations

Re: General Process [ENDORSED]