CHEMISTRY COMMUNITY

yazminedesan1F

How do you find the oxidation number of a metal?

yazminedesan1F

it depends on the element usually

yazminedesan1F

usually i add bonds from each element to the central element and try and give them each an octet with what remaining electrons i have

yazminedesan1F

the bond that is shortest is stronger and the bonds that are longer are weakest. It goes, in order of increasing bond strength and in order of decreasing bond length: single bond<double bond<triple bond

yazminedesan1F

I was wondering if it was okay if the way we draw our Lewis structure was different from the solutions manual, in that it has the same number of valence electrons and each element is correctly bonded, but the structuring and order is different? This example is CH3OH.

yazminedesan1F

I think for the test he would give us the chemical formula since we have not gone over how to write the chemical formula from just the name.

yazminedesan1F

I was also wondering if we needed to know how to convert the wording of chemical formulas into the actual chemical formula, especially for the upcoming test, but we haven't learned about it yet. My TA gave the names for us, however, if this is helpful to you: a) ammonium chloride, NH4Cl^+ b) potassi...

yazminedesan1F

This really depends on the molecule and you'd have to access where a single or double bond should be fit

yazminedesan1F

They are at their fullest and are content that way so no

yazminedesan1F

yes usually lewis structures will have a charge outside of the brackets

yazminedesan1F

The ionic radius is the the distance from the nucleus to the outermost electrons in a ion, while the atomic radius is the distance from the nucleus to the normal valence electrons. The ionic radius in a positive ion is less than the distance from the nucleus to the valence electrons and the ionic ra...

yazminedesan1F

Generally, in the order their given I would put them in that order, for example if given the percentage of C,H, then O, I would write it as CHO. It probably doesn't matter but to be safe I would keep them in order :-)

yazminedesan1F

Megan Potter 1G wrote:How far in the periodic table do we need to know for electron configuration stuff? To krypton (so 3d, 4s, 4p)?

Im assuming its only up to the d orbital, not the f orbital.

yazminedesan1F

A bullet of mass 2.8 g travels at 373.23 ± .34 m/s. What is the indeterminacy of position?
could someone explain this question and how to do it? thanks!

yazminedesan1F

Nienjou Claire 1E wrote:Also, does anyone know where we can get practice midterms? Does the test bank have any?

These arent lavelles exams but it is good practice from Scerri! http://www.bruintestbank.com/chemistry/

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DomMaiorca_1I wrote:Will we need to be able to draw electron configurations for the midterm?

Yes I believe we should know how to draw them or at least write them seeing as we've done so in class

yazminedesan1F

" A newly designed laser pointer with a certain frequency is pointed at a sodium metal surface. An electron is ejected from the metal surface with wavelength 1.10 nm. What is the frequency of the light from the laser pointer? The work function of sodium is 150.6 kJ∙mol-1" So sometimes to f...

yazminedesan1F

How were you able to see the quiz earlier than discussion?

yazminedesan1F

the test should definitely give you the mass of an electron, proton, and photon i believe

yazminedesan1F

its usually not provided, you should probably just know a ballpark around what each wavelength represents

yazminedesan1F

l represents the type of orbital and m represents which of the l orbitals you're in

yazminedesan1F

on the equations sheet we see that the mass of an electron is 9.1095 x 10^-31 kg

yazminedesan1F

Jocelyn1B wrote:How do you balance your other classes while still studying for chemistry?

typically I set a certain amount of time each week just for chemistry, at least three times a week while also studying for a test the week before so I don't get overwhelmed

yazminedesan1F

Its just the energy required to remove an electron

yazminedesan1F

Should we understand the ranges of wavelengths of light? like the specific ranges of wavelength (visible light, UV,etc...) because I know some module questions asked that and I don't know the range off the top of my head. thanks!

yazminedesan1F

I would just use the periodic table atomic masses. I usually round when finding amount in moles to have a whole number

yazminedesan1F

I would change it to liters to keep it all consistent

yazminedesan1F

I would just in case it states otherwise

yazminedesan1F

would use for wavelength but can also be manipulated for other uses

yazminedesan1F

I would use whats given or whatever has more decimals just to be more accurate

yazminedesan1F

yes it's important to consider it

yazminedesan1F

what's the best way to learn the material for someone who's not so familiar with chemistry concepts?

yazminedesan1F

its basically a particle representing a quantum of light or other electromagnetic radiation. It carries energy proportional to the radiation frequency but with zero mass

yazminedesan1F

usually I round to however many numbers are in the question.

yazminedesan1F

typically yes you should use SI units

yazminedesan1F

If you do it the longer way, you're able to see the units and therefore can easily figure out what units you'll want in the end.

yazminedesan1F

a reactant is the starting material that will eventually undergo changes in a chemical rxtn while a reagent is the compound added to a system in order to cause a chemical rxtn. sometimes you can use them interchangeably.

yazminedesan1F

I typically use 16 just to get an even number of moles if thats what im trying to find

yazminedesan1F

Mg: 24.305 (atomic mass) x 1(amount of element) S: 32.06 x 1 = 32.06 O: 16 x 4 = 64 for the 7H20 you bring 7 and multiply it by 2 for hydrogen to get 14 hydrogen and 7 multiplied by one oxygen is 7 oxygen H: 1.008 x 14 = 14.112 O: 16 x 7=112 add all of these and you should get 246.477 which, because...

yazminedesan1F

Hey! I'm not very sure how to go about this question G.5: A student prepared a solution of sodium carbonate by adding 2.111 g of the solid to a 250.0-mL volumetric flask and adding water to the mark. Some of this solution was transferred to a buret. What volume of solution should the student transfe...

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