Marconis

Nevermind! All set!

Hey guys. I posted this in the homework forum, and I am sort of in desperate need of a response. I understand if this post is deleted. So we just learned how to do ICE charts for equilibrium, and with this problem in particular I am having some difficulty..I don't know if I set the equation up properly. Thanks a bunch A mixture of 0.546 mole of carbon monoxide and 0.407 mole of bromine was placed into a rigid 1.21-L container (i.e. these are initial amounts) and the system was allowed to come to equilibrium. The equilibrium concentration of COBr2 was 0.246 M. What is the value of Kc for this reaction? Use an ICE table to help you. Round your answer to three significant figures. CO+Br2<----->COBr2 I .45124 .336364 0 C -X -X +X E .45124-X .336364-X .246 (.246)/ (.45124-x)(.33636-x)=x Solving for x I got: .9153 as Kc Merged post follows: Consecutive posts mergedScratch that, found my mistake!

I did that, as you can see in my equation. Merged post follows: Consecutive posts mergedAh! I asked my professor about it today, and where I went wrong is just comical! I had to use .241 instead of X. How did I not pick up on that? Oi. Thanks for the help guys.

Nobody here likes Naked Science on NatGeo? . I love that show. Mythbusters never interested me, strangely.

That's where I am getting thrown off. It said equilibrium concentration was .246, so I just put that into the equation. I don't understand any other way how to do it for that compound.

I'd appreciate any help, as I am aware that these kinds of problems are only slightly tedious. Thank you in advance! My answer seems a tad low for a Kc value, which is why I am asking on here. A mixture of 0.546 mole of carbon monoxide and 0.407 mole of bromine was placed into a rigid 1.21-L container (i.e. these are initial amounts) and the system was allowed to come to equilibrium. The equilibrium concentration of COBr2 was 0.246 M. What is the value of Kc for this reaction? Use an ICE table to help you. Round your answer to three significant figures. After doing the ICE table, hopefully correctly, I got the following equation: (.246)/ (.45124-x)(.33636-x)=x Solving for x I got: .9153 as Kc Merged post follows: Consecutive posts mergedNah, nobody?

I just found a way to do it using inverse log. Thanks guys

This is for Gen Chem 2. My mathematical knowledge is pretty slim, lol.

The radioactive isotope tritium decays with a first-order rate constant k of 0.056 year-1. What fraction of the tritium initially in a sample is still present 30 years later? By using the formula .693/K, I get the answer 12.375 years is the half life. I am honestly stumped as to what is next. Any guidance would be greatly appreciated. Thanks

Nevermind, I got it!

Ok, your reasoning is the correct one and parallels mine, so I understand. Thanks for your help

Ah, it is MnO2. Is that because the molecular formula is Mn4O2, then when you do "cris cross" it is Mn2O4, empirical formula MnO2? Merged post follows: Consecutive posts mergedI rebalanced it and am getting the correct answer. Thanks for pointing that out! I had forgotten that the roman numeral meant the charge and not the amount.

MnCl2 + 3Cl2 + 4H2O ----> MnO4 + 8HCl I am pretty sure I balanced it correctly.

So I am reviewing for my final on Wednesday, and this question just has me baffled: What is the limiting reactant when 31.3 g of manganese (II) chloride, 48.3 g of chlorine, and 25.7 g of water react to produce manganese (IV) oxide and how much hydrochloric acid is produced? I determined that MnCl2 is the limiting reactant. After balancing my equation, I get: 31.3(1/126)(8/1)(36)=70 something The answer it is marking as correct is 36.3g. What am I doing wrong? Thanks.

Really sorry for wasting your time. I counted decimals incorrectly when looking at the answer in Joules, and it wasn't even a selection for an answer, which is why the correct one was in kJ. Disregard this entire thread. Once again I apologize for my stupidity.

My fault, I didn't divide by avo's number in the first one...not sure why I thought I did. However, I still don't get why the answer is in kJ, when it is asking for J. And, like I stated, another very similar question (which I displayed) had the answer in J as opposed to kJ. It was literally the same question just different wavelengths. Thanks

So I am doing lots of studying for my GenChem I final next Wednesday. Surprisingly, stuff I didn't get before is now coming rather easily . One thing that I am confused about, though, is the following question: What is the energy in joules of a mole of photons associated with visible light of wavelength 486 nm? I know how to work it out and everything. When worked out, I get the answer 2.46 × 10-4 J. However, the answer marked correctly (I looked it up on the net, too) is 246kJ. Why is the answer in kJ even though it is asking for joules. This isn't so baffling as the fact that another question almost exactly like it has the correct answer in J. Can anyone shed light on this? Thanks a bunch. ***Edit, one more thing. How come in the following question I have to multiply by avo's number when in the former one I had to divide?*** What is the energy in joules of a mole of photons associated with red light of wavelength 7.00 × 102 nm? (This answer actually comes out to joules, too) Thanks again!

I'll be alright. Last night I was just really stressed with the homework I was doing. Wound up doing it again tonight, and took your advice about keeping track of units. It all sort of clicks once you realize that they are all working towards the same thing in the grand scheme of the equation.

Well, for now my main interests are along the lines of bacteria/viruses(chem heavy I'm sure) and ichthyology/freshwater/marine ecosystems(been keeping aquariums all my life). Evolution and genetics as a whole fascinate me as well, but my main interest lies in the former. So, I'd have to go with microbiology.

I suppose it is the concepts. Let's say I am learning how to do something such as solubility/colligative equations. I can learn one type of equation, but when another type comes up that is ultimately the same concept as the previous, I start to struggle and cannot seem to apply the same logic as to the previous equation.

What I meant simply is that botany was my least favorite area of study in biology as of yet. It isn't that I don't love science as a whole; I truly love science despite my dislike for chemistry. Science is the only thing that excites me in life, and what I meant in my thread is that I fear my difficulty in the subjects other than biology may hinder my progression.

I apologize for the very similar thread to the one below me, but after explanation they are rather different. If one were to look at my post history, they'd find my own threads to be rather repetitive, but I need to post this. I am a freshman biology major at a state university. Since I was young, I had always been interested in biology. That's my issue though: Always been interested in biology. In high school, I disliked math, chemistry and never took physics. I took AP Biology last year and it was the best thing I ever did. I proved to myself that I did in fact enjoy biology, studied my ass off, and wound up getting a 5 on the exam. My attention never shifted during class (botany is a different story). Anyway, when applying as a biology major to colleges, I had a lump in my throat as I knew that I was not born a scientist, and would have to work like no other to be good at science studies in general. So, here I sit. In bed after nearly having a panic attack when doing chemistry homework. I am finding general chemistry to be extremely difficult at times. Sometimes it's a breeze, but others are tedious. I have an A in the class right now, but the final will probably destroy that since we only do homework and no exams. I dislike math, but am actually doing very well in my college algebra class (wasn't ready to do precalc/calc). After that little background, my main question is this: If I am so narrow-minded, and am only really interested in biology, am I doomed for a career in science? I am well aware of how closely related chemistry and biology are, and I feel if I suck at one then I have pretty much failed as a well-rounded future scientist. Biology is the only thing that excites me, and a career in it is all I can picture myself doing. I worry, however, that my distaste for chemistry as a whole and difficulty in math is going to be an enormous roadblock for me for many years to come.

My school automatically puts all entering freshman biology majors down for a BA. What exactly are the differences in the two degrees? If I decide I want to graduate with a BS, when should I switch over?

A great answer. I actually talked to my bio professor today and he said pretty much what you said: to stick with general bio for now, and then take classes closely related yet specific to what I want to study. My school does in fact offer weekly seminars, and I am going to try to attend them as much as possible if they seem interesting. Thanks a bunch

I am having a sort of mental conflict. I am a biology major (freshman) at University. The reason I chose this is because, well, I love the science, and in the future I would enjoy doing disease research...but is that all? No. I also have a massive interest in aquatic life, having kept three of my own aquariums throughout high school. Here is where the conflict arises...my school offers a zoology major, one of the very few on the east coast or something like that. It is very tempting to switch over because of my great interest, however my interest in general biology (and eventually geared more towards disease and whatnot) is still great. So, the question I ask is the following: If I stick to the route of a biology major, choose courses related to both of my interests, and decide what I want to do at the last minute (say, in the end, I want to work with fish) then is a degree in zoology more suitable? Another way of asking is, do you think I'd have a greater chance of getting employed somewhere with a degree in zoology as opposed to biology in relation to that interest? Dumb question? Perhaps, but it's late and I have been pondering.