Chem Definition and 398 Threads

Homework Statement Al3+ N3- Li+ Au+ Sr2+ Mn2+ Tl+ Br - Homework Equations The Attempt at a Solution no clue, the positives and negatives are messing me up

Homework Statement I need to calculate the temperature and pressure at the triple point. natural log of pressure of the liquid/solid: lnp(solid)= 29.411-(5893.5K/T) lnp(liquid)=22.254-(3479.9K/T). The compound is uranium hexafluoride, MW= 352.02. I do not believe the actual molecule matters...

What is the bond order of CO+ I don't even understand how do this because C does not obey the octet rule in this case. Can anyone help?

1Q. Explain why you would expect a BeF2 molecule to be linear but a SF2 molecule to be angular? A. Beryllium fluoride would be linear because each of the two valence electrons in a beryllium atom is shared with an electron from a fluorine atom. Using the valence electron-pair repulsion theory...

Homework Statement What is the total number of atoms in the molecules? NH3 - 2.5 mole Homework Equations Would you multiply the number of atoms in NH3 by Avogadro constant to find the number of atoms? (4 atoms)(6.02*10^23) =answer Or would you multiply the number of moles by Avogadro...

i might get confusing cause i don't understand this very much but here is the copy of my lab i need help with #1 & 6 of the POST-ALAYSIS here is the word doc. of my lab http://courses.digitaldapp.org/documents/Inquiry%20Lab%20-%20Experiment%2003%20-%20Composition%20of%20a%20Hydrate.doc...

Homework Statement Write the balanced net ionic equations for the reactions, if any that occur between: NiS(s) & HCl(aq) My attempt: NiS(s) + 2HCl(aq) -> NiCl2(aq) + H2S(s) NiS(s) + 2H + 2CL -> Ni(aq) + 2CL + H2S(s) NiS(s) + 2H(aq) -> Ni(aq) + H2S(s) My real question is...

H2SO4 (aq) + 2HI (aq) --> SO2 (g) + I2 (s) + 2H2O (l) Indicate the oxidizing and reducing agents. ----------------------------------------------------- I started by assigning oxidation numbers to all the atoms: H=+1 O=-2 S=+6 to +4 I=-2 to 0 I think H2SO4 is the reducing agent and...

An instrument can detect 9450 photons of light of wavelength of 8.065 × 10^-8 m. What is the minimum amount of energy in J to which the instrument is sensitive? Express answer in scientific notation.. i have tried to use the e = (planck's constant) ( speed of light ) / (wavelenghth) but i am...

Hi This is my first science subject ever, and I am having difficulties so I would love to have all the help I can get please. My assignment is about Lewis structures and empirical formula for the following Homework Statement 1.potassium iodine, 2. calcium flouride, (these two are...

Homework Statement how would you draw this structure in 3d using dash-wedge representation? HN=C=CH2 From my guess, I drew the N=C=C as being parallel, and the two hydrogens coming off the second C without having any dashes or wedges, but curving at 120 degrees from the carbon. For the...

subjects like Solid state chemistry, QFT, QCD, general relativity, particle physics, etc look interesting to me and i really would like to master them at some point. so far i have taken basic physics, calculus i-iii, introductory courses to ODE and PDE, pchem, and 2 introductory modern...

I was wondering does bromide react with propanol or propanal at all? Also, what answers do people get for this question, i say it either propanol or propanal as i don't know if either reacts with bromide and both would be a suitable answer. The question is: Compound A has a molar mass...

Hi, I'm wondering how can i differentiate when the molecule is an SP3, SP2 or SP hybrid orbitals? Like for example C2H2 and C2H4. What can i do in order for me to know?

This doesn't seem like it should be too hard, but I'm stuck... Am i making a stupid mistake somewhere? 1. The density of potassium metal is 0.89 g/cm3. Potassium's atomic radius is 231 pm. Assuming that r nuc = 10^-4 x r atom, estimate the density of an essentially spherical 39K nucleus...

I'm going to be a senior in hs this fall and am still fretting over my schedule. It's either IB Chem or AP Comp Sci A. I can't take ap chem because i don't have space for the dbl pd class but ib covers most of it and with a little self-study (i have had friends who successfully done this...

Homework Statement Name the following compound: CH3CH2C(CH3)2CH(CH2CH3)CH2CH2CH3 It's an alkane (Is there a way to see that it's an alkane when it's in this format?) Homework Equations The Attempt at a Solution I really have no idea where to start. I can name compounds...

Homework Statement Find the molarity of the solution (salt and any excess reagent after reaction of 250 mL of 0.05 M Ba(OH)2 with 200 mL of 0.08 M HNO3. Homework Equations The Attempt at a Solution I am drawing a blank. Here's the balanced equation Ba(OH)2 + 2HNO3 ===> 2H2O + Ba(NO3)s...

Hi, I was wondering if studying these CHEM courses all in the same year would be too much for a person that is studying Biotechnology, and thus I am taking 4 other Biology courses with another needed humanities credit. The CHEM courses are: Fundamentals of Analytical Chemistry...

Could someone explain to me how to solve this? I have a 10 gallon solution made up of 6.40%Cl, 5.52%Na, and 4.11%Ca, with a density of 1.21. How much HCl is needed to get the %Cl up to a 6.60%, and what would the theoretical %Na and %Ca be after the HCl addition? Can anyone show me the...

I am an undergrad student studying chemistry and I was wondering from the pros what classes you thought were the most interesting or helpful after school.

How necesary is Programing C for a civil engineer or all engineers? Why do colleges require some programing for engineers. Also for a civil engineer, how important is GENERAL CHEMESTRY 2, since is not mandatory at the University i'll be transfering, but it is a transferable course along with...

Can someone please help me with this back tritration problem! a 100.0 ml sample of spring water was treated to convert any iron present to Fe2+ (AW 55.847) Addition of 25.00 ml of .002107 M K2Cr2O7 (FW294.185) resulted in the reaction: 6(Fe2+) + (Cr2O7)(2-) + 14H+ _____6(Fe3+) + 2(Cr3+) =...

It's been two years since I finished CHEM 1411, and I'm taking CHEM 1412 (General Inorganic Chemistry 2) this summer. What should I review specifically from 1411 to be adequately refreshed? Thanks.

[Xray reflection 1. Homework Statement X-rays of 1.54 angstroms are reflected off copper powder @ 21.65º 25.21º 37.06º 44.96º 47.58º Find the cubic lattice and the length of an edge of the unit cell. 2. Homework Equations nλ = 2d sin(Θ) ; the Bragg equation 3. The...

Hey guys, I am studying for my final for Gen Chem and will be taking the ACS gen chem exam this week. Has anyone here taken it before and if so, what equations and/or constants will be given? Thanks for the help guys! Medline

A bauxite ore 86.0 percent Al2O3 by weight. How many grams of the ore are required to produce 20.0 grams of aluminum metal? (Formula masses: Al2O3=102 & Al=27.0) A) 12.3g, B) 32.5g, C) 37.8g, D) 43.9g So this is how I did it on the test but got it marked wrong. I reasoned take 1/.86=1.16...

Hi everyone, I was wondering what you all recommend for studying/reviewing Introductory University Chemistry. I heard good things about the Silberberg textbooks, while I used Zumdahl at my school. So I was wondering, do you all think that Silberberg is better or should I maybe study a bit...

We've been doing syntheses for a little bit in class and I just can't get these. I'm having trouble taking the final compound and figuring out how to synthesize it from the starting compound(s). I feel like I'm better using reverse synthesis but I'm still getting stumped on that. I just can't...

Hey guys, I'm back, finished my term in physics with a 96% final grade, thanks to all you guys. So i thought id try you guys before i went to find a chemistry help forum. I get the Mole Concept, kinda, here's an example question (i got an answer, not sure if its right, we don't get a "back...

If a person drank methanol, they would go blind, and their breathalyser analysis (in units of mg/100 mL blood) would be in error. Its reading would be?

I have a lab question that I'm stuck on. For your assigned molecule evaluate the energy barrriers to the rotation: from anti to gauche from gauche to gauche from gauche to anti I have data/graph of steric energy vs. dihedral angle of 1-chloropropane, but I don't know how to use...

help with this chem question please! Homework Statement One reaction that produces hydrogen gas can be represented by the unbalanced chemical equation: Mg(s) + HCl(aq) --> MgCl2(aq) + H2(g) What mass of HCl is consumed by the reac- tion of 3.54 mol of magnesium? Answer in units...

in order to plate a steel part that has a surface area of 200 in^2 with a 0.002 in thick layer of nickle, how many atoms of nickle are required not looking for an answer i just need help on what to do. i know how to find how many atoms of somthing when given the weight. just not sure what to...

Homework Statement Are these two structures resonance? if not why not? Homework Equations The Attempt at a Solution I drew these resonance forms myself, but the answer book didnt' have this resonance structure in its answer and i wanted to know if this indeed is a...

[SOLVED] Organic Chem - Resonance Structures #2 Homework Statement Trying to figure out this resonance structure...Draw the lowest energy alternative.. http://img162.imageshack.us/my.php?image=553562cu7.jpg The Attempt at a Solution ive been trying to move the upper double bond...

Homework Statement 1. Ozone has a maximum concentration of 4.7 x 1012 molecules/ cm3 at an altitude of 20 km. The total pressure at this altitude is 100 torr. Using the ideal gas law, what is the mole fraction of O3 at that altitude? Now express the mole fraction in ppb. Homework...

Hi everyone (me again), I am currently in my first year Chemistry course, s its really general in the sense that we are covering broadly about every topic in Chemistry (except for the specialized ones). Now we just started organic chemistry and I noticed not a lot of math is involved, so I...

I have a final coming soon in Chemistry, and it is going to be comprehensive. I am really nervous about it, and I am not sure of a good study strategy. I know I can't read the entire book in a week, so I was hoping someone might have a good study plan for a comprehensive exam. Thanks in advance

Hope I am posting this question in the correct forum, I was not sure as there are so many. Anyways, I am in finals week for Intro to Chemistry class. It really put me through the ringer, I mean I had a hard time in this class, and yes I studied. Now I need to take Chem 200 or General Chem...

Homework Statement Explain what happened when the solution was added to water in terms of Le Chatelier's principle and ocument your explanation using observations. Think Carefully! write out the correct mass action expression before you answer--this is subtle! Homework Equations a...

Hey guys, I have a question about one of the problems on my practice chem exam for which the prof. does not give the answers to. This guy also really likes to use trick questions and so I am not sure if this is one or not. I know it is an easy one but I don't want this to be a trick question and...

I need to write a balanced equation for a reaction between water solutions of nitric acid and magnesium hydroxide. I'm stuck and I'm sorry I don't know how to type in subscripts, so I can't write out the formula on here. Any help?

i really liked Gen. Chem b/c it involved calculations and i miss that, what's the next Chem course I can take that is heavy in Math in Chem? also, i understand and know most of the things that is expected from a 1st yr Organic student, it's just not that appealing to me.

1) Calculate the pH of a solution prepared by dissolving 0.370 mol of formic acid (HCO2H) and 0.230 mol of sodium formate (NaCO2H) in water sufficient to yield 1.00 L of solution. THe Ka of formic acid is 1.77 x 10^-4. a) 2.30 b) 2.09 c) 10.46 d)3.54 e) 3.95 2) The solubility...

Hey, I have a worksheet due tomorrow for my chem class and it includes #9 from the 1997 FR AP Chem Test. I can't figure it out! Any help would be appreciated! Here goes: An experiment is to be performed to determine the mass percent of sulfate in an unknown soluble sulfate salt. The equiptment...

We recently did an experiment in chem lab with titrations and we are supposed to find out the molarities of some unknown solutions. I thought that I was doing my calculations right, but the checking program that I am using keeps telling me that I am wrong. We made a standard solution that was...

[SOLVED] Chem Lab Help! My AP chem class did an experiment where we started with 0.500 grams of copper and we ended up with 0.525 grams of copper after the experiment. The experiment consisted of us sending copper through different reactions to observe the effects of a series of reactions on...

Problem: Determine concentration of H2O2 with Titration of KMnO4 Balance the equation and create a net ionic equation then balance using redox techniques and replace spectator ions Balanced Equation: 5H2O2 + 2KMnO4 + H2SO4 ==> K2SO4 + MnSO4 + H2O + O2 My Work: I eliminated all spectators and...

Homework Statement 0.2500 g sample of an Aℓ-Zn alloy reacts with HCℓ to form hydrogen gas: Aℓ(s) + 3H+(aq) → Aℓ3+(aq) + 3/2H2(g) Zn(s) + 2H+(aq) → Zn2+(aq) + H2(g) The hydrogen produced has a volume of 0.147 L at 25°C and 755 mm Hg. What is the percentage of zinc in the alloy...