Chem Definition and 424 Threads

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...

I have a problem where I am given an equation of state pV=RT+(bRT-a)/V and asked to find the work produced in the isothermal, reversible expansion from V1 to V2. I thought I would want to use W=-integral(nRT/V)dV, but that is apparently only for ideal gases, and this problem concerns a...

Homework Statement 5.00g alloy of Magnesium and Aluminum is treated with excess HCl, forming MgCl2 and AlCl3 and 6.65L of H2 at 25 degrees celcius and 99.2kPa. What is the mass percent of Mg in the alloy? Homework Equations PV = nRT The Attempt at a Solution Using PV = nRT...

Homework Statement Hydrogen peroxide decomposes into water and oxygen gas with the help of a catalyst. write the molecular formula and the redox half reactions. Homework Equations (N/A) The Attempt at a Solution the molec. formula is of course 2 H_{2}O_{2} (l)...

Homework Statement Balance this redox equation. Homework Equations Ag + H^{+} + NO_{3} ^{-} \rightarrow Ag^{+} + H_{2}O + NO The Attempt at a Solution Using a conventional balancing mechanism I got these coefficients: 1 + 8 + 2 -> 1 + 4 + 2 but the correct...

[SOLVED] help setting up a CHEM E problem Homework Statement Three fillers used in packaging a pharmaceutical emulsion (ro = 1050kg/m^3) are fed from a single product line. One filler has a capacity of 2700kg/h, the second operates at 4600 kg/h and the third at 6800 kg/h. The emulsion is...

Hi, I'm taking AP Chem this year, and we just had this big assignment. I got through most of it, but here's some I need a walkthrough with. Homework Statement A titration is done using .1302M NaOH to determine the molecular weight of an acid. The acid contains one acidic hydrogen per molecule...

here is the question: The entire contents of one of the Erlenmeyer flasks used in the oxalate-permanganate titration in Experiment 8 was poured into a 250 mL volumetric flask. The volume was made up to 250 mL. A 20 mL portion of the solution was placed in a 100 mL volumetric flask and 20 mL...

Homework Statement In lab, a student decides to analyze a 0.6118 g sample containing only magnesium chloride and sodium chloride. He does this by adding 145 milliliters of 0.1006 M silver nitrate. A precipitate, silver chloride, is formed, which has a mass of 1.7272 grams. Using this data...

Is anyone here able to help me or point me in the right direction? Iron ores often involve a mixture of oxides and contain both Fe 2+ and Fe 3+ ions. Such an ore may be analyzed for its iron content by dissolving it in an acidic solution, reducing all of the iron to Fe 2+ ions and then...

I have to take a second semester General Chemistry course (qualitative analysis) in community college. I took quantitative analysis about 3 years ago, and I didn't need it for transferring to CSU Long Beach, but I've decided to go to a different school now and I need to take it after all. My...

Homework Statement A sample of 2.00 mol. CH3OH (g) is condensed isothermally and reversibly to liquid at 64*C. The standard enthalpy of condensation of methanol @ 64*C is -35.3 kJ/mol. Find w and q for the reaction. Homework Equations w = -nRT * ln(Vf/Vi) (although I don't have volume...

Organotin compounds play a significant role in diverse industrial applications. They have been used as plastic stabilizers and as pesticides or fungicides. One method used to prepare simple tetraalkylstannanes is the controlled direct reaction of liquid tin(IV) chloride with highly reactive...

Homework Statement A solution is made by disolving 0.40 mol isopropanol (C3H7OH) in 0.70 mol water. (a) What is the mole fraction of isopropanol? (b) What is the mass percent of isopropanol? % (c) What is the molality of isopropanol? m Homework Equations...

I have just started AP Chemistry this year as a junior at my high school despite all peer protests against it. And I admit so far the course has lived up to it's reputation of being very difficult. I was rather ecstatic to come across this site where I may obtain the help I /know/ I will need...

Hello, I need to make sure I understand some of the reactions correctly... For example: CH2OHCH3 in H+ will give us CH2=CH2. I would think that here the H+ bonded with the OH resulting in H2O (a leaving group), but I am not sure what happens to the other leaving H. In RC≡CR' in Na/NH3...

Hi, I was just wondering if anyone had any advice on sources of steam ejector design principles. I've seen one textbook on the topic of steam ejectors that is now out-of-print, and haven't been able to find any suitable online resources (generally, they're very basic and don't quantify much...

I'm a chemical engineering undergraduate studying in Canada right now. I'm not too sure what my future looks like, so I'd like to have some opinions on whether it's a good engineering discipline to stick with. 1. I'm interested in a career in R&D, but I hear that you need at least a PhD. I'm...

we ofen hear the terms organic, natural and chemical in the media. Organic and natural are usually used to imply that a product is "healthy" and/or "environmentally friendly" while chemical often implies negative implications for health and for the environment. In your opinion are these...

P. Chem--advice? I know, a physics major taking P. chem...why would he put himself through that? However, the topic has peaked my interest and it appears that what I want to do research on will require a knowledge of P. Chem, so my question is simply: Anyone have any survival advice? The...

Hello, I needed some help with my Chemistry Homework. I have 4 questions that I'm not so sure of the answer. I've given my best try. Please if someone can help me correct my answers or tell me which one is the right one and how to determine/solve it... Thanks in advance. Question One...

hi all.. this is rohan here. It's time for the high school chem project, and i want to do a project on toxicology, though if i get a better idea in any other subject [related to chem], i'd do that too.. so.. I'm asking you for an idea for a high school chem project.. and preferably one on...

Can some body please help me on my homework. The problem is in the link image below (click to go to it) http://img501.imageshack.us/img501/1126/helplr7.jpg" I'd know how to do that problem if it said "initial rate (M/s)" in the last column, but it says "Reaction time (seconds)" and I...

Homework Statement My questions pertain to #4b of the free response. Question: Excess nitric acid is added to solid calcium carbonate. The question asks to predict a balanced equation for this reaction. The Attempt at a Solution what I wrote down was: H+ + CO3 ----> H2O...

Homework Statement All I'm trying to do is translate the cell diagram below into a into a an equation so I can determine which is the anode and which is the cathode. Here is the cell diagram. I know how to balance it, I just want to make sure I'm putting reactants and products on their...

I'm very confused with an electrochemistry lab. For the lab, we used Al+3, Cu+2, Fe+3, Zn+2, and KNO3. The setup was wells with all of the solutions in them. We soaked a piece of paper(filter paper) in KNO3 for the reactions, then used the paper as a salt bridge between the solutions of the...

After drawing the 8 alcohols with the formula C5H11OH, I'm asked to "Describe how they are formed and give two uses for this type of alcohol." The only example in my text for this is the hydration of an alkene which, at a glance, wouldn't make sense for 2,2-dimethyl 1 propanol. Is this one...

This is the question: If 20 mL of a 0.3M solution of NaOH is required to neutralize 30.0 mL of a sulfuric acid solution, what is the molarity of the acid solution? I just need to get pointed in the right direction and then just some simple steps from there... Thanks H20h

Homework Statement The standard Gibb's free energy for the reaction N2+3H2<--->2NH3 is -33.0 KJ at 298 K. Everything is a gas. Calculate Kp for this reaction. Homework Equations I have in my notes that Keq=e^(-Delta G/RT) where R is the constant 0.008314 KJ/K. I also have a formula...