Homework Help

Hi does anyone know how to assess the purity of the DNA sample, the 260/280 ratio for pure DNA is 1.8- 2.0 ? I extracted the DNA and my concentration was ng/ul 45.1 and the optical density was 2.06. please help me solve this

hallo we have in scool had a projekt about energy i choose sunlight (fusion had allredy been taken) i find out solar cells was mede to collekt light from one coller more efficiently than other. So here is my question: can a solar cell colekt UV. or IR light and i that case could you meke then nerly transperrent? sorry i wrote this in the wrong forum you may answer the question i have allredy written the projeckt/report

I need help with an experiment. : COPPER IN SALTED WATER?? Changes after a few days? Please answer immediately, i need it for tomorrow. Thank you

Got a really lame question that probably has a really simple answer: I know that if you multiply the concentration of Hydroxide ions (OH-) and Hydronium ions (H+) in any solution at 25 degrees it will always add up to 10-14. This is because they are 10-7 each. I've been told/read this is because if you add and acid to a solution (something that donates protons) they form Hydronium ions increasing the concentration of H30+ ions. Why does this decrease OH- concentration? HCl + H20 = H30+ +Cl-, no more. H+ increases OH- stays the same. Should be H+= 10-6 and OH- =10-7 = 10-13. I can't get to grips with why one affects the other. If it is because H+ react…

this question is belong to 4th edition of J.L . Meriam >>> prob 3/23 i wanna know whats the difference between these two cases? why the accelerations come difference ?

1. Write a balanced chemical equation to represent the reaction between iodine and propanone in acidic medium. 2. Explain why the concentration of iodine in the reaction mixture can be expressed in terms of the volume of sodium thiosulphate added. 3. Does iodine take part in the rate determining step of the reaction between iodine and propanone? Thanks a lots!

So I know I said that I only had one question, but it looks like I have another one. The question on my assignment is as follows: A medical technologist became very confused at the result of a CBC she completed on a patient. As she went to pick up the tube off of the mixer, she noticed a large number of very small clumps in the tube. After she put the tube in a beaker of warm water (37o C), the clumps disappeared. She re-ran the CBC and the results looked more like the results of a patient who was actually alive. What could have caused this clumping? I'm really not sure what this clumping could be. I'm torn between 2 answers here. The first: the clumping is th…

How do u create an activity series? Bah... I honestly dont get this. Its electro chem Question: Consider the following lab data, gathered from two different students Student 1: Lab data for the determination of an activity series of metals Chemical | Ag+(aq) | Ni+2 (aq) | Pb+2(aq) | Zn+2 (aq) -------------------------------------------------------------- Ag(s) |//////////////| No change | No change | No change -------------------------------------------------------------- Ni(s) | Grey coating| /////////////| Black coating| No change forms on nickle forms on nickle ------------------------------------…

I'm finishing up an assignment for my pathophysiology class and am stuck on this one question: Three patients are diagnosed with different types of cancer. One patient is a life-long smoker and has lung cancer, one has active Crohn disease and has colorectal cancer, and the other is a farmer with newly diagnosed melanoma. Other than the obvious thing, cancer, what do these individuals have in common? The only thing that I can think of is that all three of these cancers are the result of carcinomas. Am I over thinking this question? I have a hard time believing that something so simple could be the answer. Thanks for all your help!!!

Here are the two questions I am stuck on: "A real valued function has the property that the absolute value of the function is differentiable at o. Show by example that the function need not be differentiable at 0. Prove that if we require the function to be continuous at 0 then the function must be differentiable at 0." For the first part I was thinking of: [math] f = x^2+2x [/math] for [math]x \leq 0 [/math] and [math] -x^2-2x [/math] for [math] x > 0 [/math] Looking at the derivative of f at 0 we see that the LHD=2, while the RHD=-2, so the function is not differentiable at 0. However, looking at the absolute value of the f we see we have the deri…

Why does the production of hydrogen gas increase if you increase the amount of salt placed and the increase of voltage?

Guys, I need your help. Where can I get the proteome of Alkalophiles, i tried getting here: http://expasy.org/sprot/hamap/bacteria.html but i only got 7 proteome. I need at least 20. Anyone?!? Any help is much appreciated!

Hi, I'm doing a science fair project and it involves growing bacteria (E. coli) and determining the effectiveness of garlic in fighting bacteria. The link is here: http://www.all-science-fair-projects.com/project1098_39_2.html I have a couple questions about this project... 1) How long would it take me to grow the E. coli without an incubator? I have an empty oven that (I think) maintains a constant temperature, and I have a heating pad; would I be able to use any of those as an "incubator?" 2) Why is it necessary to add the E. coli specimen to milk before putting it on the agar petri dish? Also, this is irrelevant, but in case the topic above does not work out…

Hi, I need help in my Thermodynamics Homework. The question is that, A rectangular steel tank having an internal volume of 1 m3 contains air at 2.5MPa and 20°C. A relief valve is opened slightly allowing air to escape to the atmosphere. The valve is closed when the pressure in the tank reaches 350 kPa. a) Calculate the amount of heat that must be added so as to keep the tank contents at 20°Cthroughout the process. B) Calculate the final temperature if the process takes place adiabatically. -- I have done the a part, using the first law of thermodynamics. I have posted it. I also tried to solve b with the same analysis but it failed because the equation at …

Show that if U and V are subspaces of R^n and U intersect V = {0}, then dim(U+V)=dimU + dimV. U+V = {z|z=u+v where u in U and v in V} All I know is the two vectors U and V pass through the origin. ie. they intersect at 0, origin. How do I go about it? Thank you.

1. Use MATLAB to compute the DFT { d0 , d1 , d2 , d3 , d4 , d5 , d6 , d7 } for the following data and plot the data y0 = 0.324 y1 = 0.456 y2 = 0.112 y3 = 0.202 y4 = 0.654 y5 = 0.234 y6 = 0.678 y7 = 0.867 2. Plot the trigonometric polynomial tn(x). ================================= for the 1Q: I have this so far. so far. i have this: y=[0.324 .456 .112 -0.202 -.654 .234 .678 .867]; x=[0, pi/4, pi/2, 3*pi/4, pi, 5*pi/4, 3*pi/2, 7*pi/4] plot (x,y) Is that right? But for the 2, I have no idea how to get started with the MATLAB. I googled it, but no useful info is found. Please someone help me. Thanks a lot.

Well we are doing a project in school and we are suppose to explain things that dont make sense in this lab report. I really didn't get this so my teacher gave me a practice lab report and told me to ask around to see if anyone could tell if anything is wrong. So I just want to ask anyone if they can identify the things that are wrong in this lab report.

Well we are doing a project in school and we are suppose to explain things that dont make sense in this lab report. I really didn't get this so my teacher gave me a practice lab report and told me to ask around to see if anyone could tell if anything is wrong. So I just want to ask anyone if they can identify the things that are wrong in this lab report. http://www.mgjhscience.net/voight/wp-content/uploads/2010/11/transpiration.doc

Hi, Does anyone know how to calculate the standard deviation and mean on casio fx-83GT PLUS calculator? does anyone have the same calculator and has worked out these using it ? thanks

Hi, I need your help in my homework. My Instructor asked that question? Why there is not a work term in entropy balance equation? I have researched about it and I found that, entropy has not an exact physical meaning, however it is associated with disorder or randomness. In another point of view, entropy defines the energy which is unable to do work. however I am not sure that these definitions are enough. On the other hand, I think entropy is a mathematical derivation, which is done by a purpose of having a balance equation which does not involve a work term. They have originated it from the one directional flow of heat (from high temperature to low). Is i…

Can someone please help me with this question? Given sets A, B, C and D. Each volume contains exactly six elements. Each section of the two of them (A ∩ B, A ∩ C, A ∩ D, B ∩ C, B ∩ D or C ∩ D) contains exactly two elements. a) Give a concrete example showing that this is possible. b ) How many elements contain the amount of (A - B ) × (C - D)

Find < px >,< p > and < p2 > for the 1s electron ofa hydrogen atom. i am tried the solution but momentum operators Differential for x or y or z and the wave equation depends on the r !!

HCO3-, F-, I- and LiH. I do not know how to approach it. I could guess, but I have no method of finding this.

A steel projectile is shot horizontally at 20 m/s from the top of a 49 m high tower. How far from the base of the tower does it hit the ground?

Hi, I'm doing a panel presentation where I must present all the issues surrounding a topic. My subject is 'Should Humans Be Cloned', and I need at least 85 people to take this survey. Here's the link: http://www.surveymonkey.com/s/8MJP8FK Thanks in advance for any help.