Chemistry

i have done an experiment using colourimeter to find the rate expression of the reaction between iodine and propanone. there were 3 sets of reaction mixtures 1. 4 cm3 of propanone, 2 cm3 of 0.05M iodine, 4 cm3 of 1M HCl, 4 cm3 of water 2. 2 cm3 of propanone, 2 cm3 of 0.05M iodine, 4 cm3 of 1M HCl, 6 cm3 of water 3. 4 cm3 of propanone, 2 cm3 of 0.05M iodine, 2 cm3 of 1M HCl, 6 cm3 of water i obtained 3 graphs of [i2] against time, and i found the slopes of them 1. -0.00647 2. -0.00367 3. -0.00375 what are the possible explanations for the slope of set 3 slightly greater than that of set 2?! is it only becoz there's some error when plotting the graph, or t…

Ok got a problem. There is a 140mmol/L stock standard of Na and the working standard made from this is 70mmol/L. If i follow the instructions i get 6.4mmol/L of Na. Instructions: Mix: 0.50mL Li standard 0.025mL Na stock standard (140mmol/L) 4.475mL water If i mix these my calc. shows it'll be 6.4mmol/l calculations: 140mmol/L / 1000 = 0.14mmol/mL <-L to mL 0.14mmol/mL * 0.025mL = 0.0035mmol/0.025mL <- how many moles are in 0.025mL 0.0035mmol/5mL <-becasue there is five mL total in the mix 0.035mmol/5mL * 200 = 6.4mmol/L <-converting 5mL into 1L please can someone help me find out w…

Hi, I am intrested in learning eventually about biochemistry but I am still learning the basics of general chemistry. I don't know a great deal about physics and am having a hard time distinguishing between chem and physics at times. My goal is to be a molecular biologist and was wondering what physics if any would i need to learn, or will thorough chemistry knowledge be enough? Thanks for any info

Hi, you know how you can't do physics without math, is chem the same? If so, what main areas are essential to learn? Thanks for any info

In chemical reactions, the mass of the reactants and the product are the same right? But in fire, energy is released, so if the mass was still exactly the same after you burned something, then you would have gotten some energy free! I don't get this I learned this in science class, grade 8 so do you think that they just didn't bother explaining that?

Hi, I'm taking a grade 11 course and I was wondering if someone could explain a few things for me. What is a molecular element? For example, I have a question that says: Classify each of the reactants and products as ionic compounds, molecular compounds, or molecular elements. Another question I have is: is there a difference between a covalent bond and a molecular bond? And if there is, what's the difference? Finally: How do you know whether hydrogen is acting as a metal or nonmetal? For example: you have water (H2O). How do you tell if it is ionic or molecular compound? Since hydrogen can go +1 or -1, oxygen goes -2, how do you know if hydrogen gives…

For a solution It says; VAPOR DENSITY: 1.3 Is VAPOR DENSITY the same as Density of that solution? And what is the unit of 1.3? Hope for inputs. Thanks.

does anyone know a good place to start with rocketry?

The greatest formation of carbon ever. It is a carbon crystal made of 900 carbons each with a triple bond. It is so amazing that it actually gets stronger over time. This is where i think everyone should talk about it and contemplate its implications

I recently (literally 25 min ago) made some Hydrogen peroxide form 3% solution. Ithink its about 30%, but i want to know for sure. how could i tst this new solutions concentraton. thxx for da help

Give an example of a covalent bond and explain what is happening at the atomic level during bonding?.....If you know the answer.. please help mee!!!!

Predict what, if any, products will be made from the reaction of silver chloride and copper. Explain your answer...!!

I have a periodic table that shows the crystal structure of all the elements. I knew metals had crystal structures, but i didnt know that oxygen was crystaline and same with helium. Are they just saying that the altropes of these elements are crystaline (like sulfur and phosporus).

I am writing a training document and am addressing HPLCs. I can not just reference the instruction manual; it's five separate manuals, dealing primarily with operations that are run by the software anyhow. I have to write a SHORT document describing the basic theory and instrumentation of HPLC that assumes no more than a single general chemistry course in a very bad high-school. Can any-one suggest any public references I could crib? [That's not cheating; its "not re-inventing the wheel".]

THis is just a quick question. I have a solution of ~0.01M primary standard Potassium iodate (KIO3)made up that happened to accidently get filled past the mark on a volumetric flask. So my question is if I leave it out for a couple of nights in a dark place to evaporate down to the mark will I loose a noticible amount of KIO3

Hello This is my very first time in using a forum and I just want to say a kind hello to everybody. My Questions are: What are Infinite Arrays? What are Layer Lattices? and What are Network Lattices? Thank you for your help

I'm trying to understand how the trends in a periodic table work for electron affinity. I've read that the electron affinity generally increases across a period from left to right, and decreases down a group but there are exceptions - which means if I have a question asking me for eg. which one, Ar or Br has a more favourable(more exothermic) electron affinity...I don't know whether its one of those exceptions or not. Can any1 explain how else I can figure out which atom has a more favourable electron affinity...electron configurations maybe, I don't know for sure?? I'm really confused. Thanx.

See, does the analyte size should be taken into consideration when choosing the three sub-types (C4, C8, C18) of silica column? I was thinking that since larger analytes may find that they have a higher retention time when the carbon chains are longer to pass thru the column. How do we go about doing this? Is size (of the analyte in the moble phase) even a factor when choosing the column (C4, C8, C18)? HPLC System: Reverse Phased-HPLC

Hey does anyone know whether the electron configurations for atoms in solid and liquid states are the same? (coz if the electron configs are determined experimentally, would different states give different electron configs?)

Today is March 17th, also known as Saint Patrick's day. A day celebrating Irish heritage and whatnot. Today can also be written as 3-17. If you look at the periodic table, what element is in the third period and has an atomic number of 17? That would be chlorine gas. What color is chlorine gas? Green. What is the 'official' Irish color? Green. Kind of freaky isn't it?

There is a company that makes reactive targets for shooting. It takes a centerfire rifle .223 cal or higher to set off. A friend of mine said it was 95% AN and 5% Al powder. Its completely legal to sale and purchase in every state, but cost 160 bucks for 40 charges of 1/2 pound charges. I know that AN is cheaper then that to buy, but is that all it takes for a good size bang from an reactive target? http://www.tannerite.com is the product in question. There is a very cool vid on there to watch too. I have some of our own vids from friends too. We blow up some really nice crap.

What are the two major catrgories that divide the Periodic Table and how can they help determine if a bond will form?

Due to the three axes x, y, and z, the apparent symmetry of various polar shapes and equations such as limacon, lemniscate, rose, cardiod, etc., and the "shapes" of electron orbitals deemed s, p, d, or f, is it possible that polar equations could describe the approximate location of electrons within these electron shell groups? Has it been tried/attempted already?

The idea of this research has arisen after we have found out a glaring contradiction between actual density of carbon in diamond and graphite, and theoretical density of carbon in fulleren C60. Our own calculations have shown, that the real structure of fullerens and nanotubes is more complex and graceful, than it is offered by the official paradigm of quantum chemistry. The results of our small research are stated here: http://vlamir.nsk.ru/WHAT_DIAMOND_SPEAKS_ABOUT_e.pdf http://vlamir.nsk.ru/THE_BERYLLIUM_BEAM_e.pdf

does anyone here have any problems with Stoichiometric Calculations? if so can someone go through the basics and give me a hand thanks Ice_Phoenix87