Homework Help

Hello SFN I got a problem concerning an experiment conducted in chemistry. We're going to submit an paper on this experiment by Monday, help is needed if this is to be fulfilled. Alright, the experiment we conducted was to examine an enzyme-catalysed reaktion through spectroscopy. The reaction is: Pyruvate + NADH + H+ -> Lactate + NAD+ We measure the absorbancy and it's change for the solution at the wavelenght 340 nm. That done, we're going to make a few calculations, this is the problem since neither I nor anyone I've talked to in my class can help me with these calculations. The subject hasn't been covered in class. The calculations are: (Be…

I know i can't change the title but i solved the problem i was looking for originally and need help with another... The question says to use an integrating factor to solve: x(dy/dx) = y + (y^2)x The problem comes at the very last part to find v' and v because of the y^2 term. The factor i'm using is: y = v*exp(-integral[-1/x]dx) where the -1/x is the term infront of the y when you divide by x and bring it across. Any pointers would be great. Thanks.

Basically we just have to write a page on what you think the most important quality of a scientist is. I have began and decided to write about skepticism. I jotted down all I could think of about why this is an important value of scientists, but it fails to meet the page-length standard. Could someone maybe give me an idea or two as to why it is?

I am having trouble doing these two problems. They are about finding the pH in solutions. Here they are: a) 1 liter of 0.1M acetic acid (pKa=4.7) to which has been added 75 ml of 1M NaOH. b) 1.0 liter of 0.1M glycine hydrochloride (pKa values are 2.3 and 9.7) to which has been added 100 ml of 1M NaOH. The pH must be determined for these problems. Any help would be much appreciated. Thank you.

Hi poeple, I would like to know the chemistry about Iodine vapor stain phosphatidylcholine in TLC experiment. What compound was formed? Thanks

I need some help with these how would you apporach them to answer it any hints: 1) whether two solvents will mix or which will sit on the top? 2) how to prepare molar solutions? 3) finding errors in transcribing results? 4) what are serial and non-serial dilution and what they are used for? Pls help thx

Hey!!! I'm a second year student, just starting an Atmospheric Science course/lab duo. My Instructor for our lectures is amazing, but the on for our lab is God awful! She reads our manual to us and doesn't explain why things "are", even when prodded by student questioning. Anyways, she recited a formula, told us it was in our lab manual, which- it isn't!- and she didn't explain where the numbers came from. I'm going to post a picture of the question and data below to perhaps communicate better, the problem. THANK YOU FOR HELPING!!! Here is the data, Here it is specifically for the example problem: This is the equation given to us, I don’t understand where th…

I'm in calc 2 and don't really remember much from trig (took it in highschool 3 years ago and my act was so high I skipped college math through calc 1, going strait into calc2). I just need all the basics in one place -- not a lesson (I remember all the basics/principles) just the identities and stuff. Especially the special angles like sin(pi/4)=1/sqrt(2) and the special triangles you use to get these angles. I remember a friend of mine used to have a sheet like this he found on the Internet that was meant specifically to be a reference (but a general website is all I really need).

Let (X,Y) have a bivariate normal pdf with correlation coefficient p and variance 1 for both X and Y. So the joint density is: f(x,y) = (1/((2*PI)SQRT(1-p^2)))*exp(-0.5*(1-p^2)^-1 * (x^2-2pxy+y^2)) Show that X and Z=(Y-pX)/SQRT(1-p^2) are independent N(0,1) variables, and deduce that P(X>0,Y>0) = 1/4 +arcsin(p)/((2*PI)) ?? Does anybody know how to do this!?

When phenol reacts with liquid bromine, three products, 2-bromophenol, 4-bromophenol and hydrogen bromide are formed. When phenol reacts with aqueous bromine, 2,4,6-tribromophenol and hydrogen bromide are formed. So what is the role of water in the second reaction of creating a trisubstituted phenol? Is there something to do with intermolecular hydrogen bonding between the OH of the phenol and the water? Why is it not usually included when drawing chemical equations for the second reaction? Thank you. =)

When the car is moving in a circle at a constant velocity, how would you figure out the forces that come from each wheel (in the case that the max friction of each tire is much greater than anything encountered). For a motorcycle i figured it out easily - it comes out to simple solving two equations: sum of torques around center of mass = 0 sum of forces on body = centripetal acceleration = mv^2/R = mRw^2 This can even be solved for a two wheeled car, where instead of the other set of wheels, you have frictionless pegs. Is there a way to solve it, or does it work in a way that the inside tires are put up to their extreme, and the outside tires try to mak…

hi I'm stuck on several problems that involve writing the net ionic eq's given the reactants. Obviously, all alkali metals are soluble no-matter-what, overruling insoluble rules. So given the eq KOH + RBH2PO4, would there be no reaction? Or, what would be the correct way to write the equation? My teacher said that all eq's react, meaning there's no 'no reaction' Also, does rubidium dihydrogenphosphate = RbH2PO4? Thanks in advance.

Ok well we are on gas laws. I understand dalton's law of partial pressures, and the ideal gas law, and graham's law but i got to Eudiometer problems, and now i'm stuck. I just dont know what to do. I tried to devise my own formula but most of my answers end up 1/100 of the actual answer. How do you answer these types of questions. Can you solve these questions and say/show how/why #1. The volume occupied by oxygen gas collected over water at 25 degrees Celcius and at an atmospheric pressure of 740 mm Hg is 155 mL. What would the volume be if the oxygen gas was separated from the water vapor and then placed in a cylinder at a pressure of 740 mm Hg? Answer: 1…

Ok i have this homework and it asks "Suppose the tilt of the earth would increase to 35°, would there be more or less variation between the seasons?" Can someone help me with this?

Does anyone have the answers for science unit 2 b2 p2 c2 - friday 18th January 2008? -------------------------------------------------------------------------------- yesterday i took an exam its called Twenty First Century Science A Unit 2 - P2 B2 C2 Friday 18th January 2008 If anyone took the exam can they tell me some of the questions, and even the answers, so i can see which 1ns i gt right. Thanks in advance THIS AINT EXACTLEY HOMEWORK COZ IV ALREDAY DONE IT BUT I DIDN'T KNOW WHICH ELSE CATOGREY IT FITTED IN

yesterday i took an exam its called Twenty First Century Science A Unit 1 - P1 B1 C1 Tuesday 15th January 2008 If anyone took the exam can they tell me some of the questions, and even the answers, so i can see which 1ns i gt right. Thanks in advance THIS AINT EXACTLEY HOMEWORK COZ IV ALREDAY DONE IT BUT I DIDN'T KNOW WHICH ELSE CATOGREY IT FITTED IN

Okay, I've got some exercises here that I need some help with. I tried to do them, but I always get to a point where I just don't know what to do... 1) A train is sitting (idle) in front of a tunnel of the length [math]d=320m[/math] so that the trains front is placed exactly at the beginning of the tunnel. When a signal was given, the train started to move. In this instant a person standing at the very end of the train started counting the time. He noted that he entered the tunnel when his watch showed the time [math]t_1=30 s[/math] and exited the tunnel when his watch showed the time [math]t_3=50 s[/math]. The motion of the train was evenly accelerated the whole …

If three methods are used to separate a suspension of sand in a solution of ammonium chloride and sodium chloride so as to obtain all three substances. Which order should these three methods be? The methods are Filtration, Sublimation and Evaporation.

kAY this is the same guy with the hho.. k i get the scam. and now i need DESPERATLY a science fair idea.. please all of you.. im dying here.. i need a science fair idea!?? pleasseeee...

i was given a formula to use for a series of problems, but i dont understand how to use it. The formula is D= 1/2gt^2

Can someone explain how to use this formula?? D=1/2gt^2 i dont get it..

I'm putting this in homework help because it's help and it would be used for an essay, so it works. Would anyone have any experience with a paper published recently-ish (before 2004 I think) about a molecular clock calculated with proteins that gave the dates of divergence for a variety of mammalian groups and included the divergence between humans and tarsiers and put the date about 55 million years ago? I found this paper a few months ago and I had it on my laptop, but it crashed, so you know how that goes, and now I can't find it again on Google for the life of me. If anyone had any other papers on the divergence between humans and tarsiers that would be ha…

If I wanted to open the jar of jam but the lid was too tightly capped I would pour very hot water on the metal lid, and I could open it easily, why does it work? If the lid is made of plastic, would pouring very hot water on this plastic lid work just as well, ? why is it so?

Well this is not really a typical homework it's just something that just came to my mind! Anyways! I was helping my brother to solve some problems is physics and few of the problems were related to power ([math]P=\frac{A}{t}[/math]). And there was this other formula [math]P=F\times v[/math]. I mean, I'd seen this formula for a hundred times, but never really paid attention to it. Then my brother asked me a question :"What is the power of an object whose mass is 5kg and which is falling from a distance of 10 meters?". OK, it's not any hard question and I just want to make sure I gave to him the right answer. This is what I did! In [math]P=F\times v[/math] instead o…

grade 8 project drop egg from small height (i think 1 ft then higher and higher, max around 10ft) only use 10 straws 10 popsicle sticks 1 meter of tape 5 rubber bands 3 sheets of paper 1 mini paper cup 1 raw egg not necessary to use all need help to think of ideas