Total # Posts: 703
I am trying to gain a understanding of the transfers and conversions of energy whilst the subject (being a diver) goes through its motions. Maybe i should be clearer .... SO as the diver makes his way to the top of the steps chemical energy is transferred from the body to the...
April 27, 2010
Hi there, would someone be able to tell me if this is right or almost right or really not right?! The scenario being explaining the transfers and conversions of energy of a diver. from walking up the steps to standing at the top of platform to jumping into pool and to start ...
April 27, 2010
hey. show 2sin(pi/14) is a solution to x^3-x^2-2x+1=0 and hint: let x=2sinu and sin(7u)=1 i can't seem to solve when i sub in the x value. how can i relate this to the seventh root of inifinity. i multiplu by sin^4 but they it just doesnt work.
April 23, 2010
What would be the product of the reaction of 4-methyl pyridine with Ac2O/AcOH and PhCHO? I'm really stuck on this. I'm guessing the pyridine will attack the anhydride and form an acyl pyridinium ion but I'm not sure where to go from there. If that reacts with AcOH ...
April 21, 2010
What would be the product of a reaction between methanal and pyrrolidine in acid? I know that normally a reaction between a carbonyl and a secondary amine would form an enamine. Here I am confused because there are no hydrogens that can be removed to form the enamine as this ...
April 7, 2010
Write the Hamiltonian operator for 2 electrons in a 1D box of length a. I know that the Hamitonian is a sum of the kinetic and potential energies. I was thinking that for 2 electrons in a 1D box it would be: -2((hbar^2)/2m_e)(d^2/dx^2)) + Coulomb interaction for 2 electrons I ...
April 5, 2010
Time dilation is the theory of time relative to motion. It is the principle that time elapsed is relative to motion, such that time passes more slowly for a system in motion than for one at rest relative to an outside observer. Further, as predicted by Einstein's special ...
March 28, 2010
Im after info that will help me answer what the relevance of the age of the oceanic crusts and the continental crusts within the south american plate Are there presence of hotspots on the south american plate? what is the process that is responsible for the change in area of ...
March 25, 2010
THANK YOU what is the magnitude of acceleration that the force 5.0 x 10³ N causes when applied to a vehicle with a mass of 1.1x10³kg??? How do i present the answer for this ?
March 24, 2010
SO desperate with help with this. What is the magnitude of the acceleration that this force will cause when applied to a car with a mass of 1.1x10³Kg Then calculate the final speed of the car (above) assuming that it was standing still initially and that the force of 5.0 ...
March 24, 2010
I have some enthalpies of formation for a reactant and transition state but calculated using different computational methods. I want to find the ratio of the forward rate constants determined using both methods but I'm not really sure how. I thought I could maybe use ...
March 13, 2010
Iron metal is dissolved in dilute aqueous HCl. The resulting solution is warmed with dilute nitric acid and then treated with aqueous potassium iodide. Write equations for the reactions. Ok so for the first step I got: Fe + 2HCl --> FeCl2 + H2 I'm guessing that when ...
March 2, 2010
I'm trying to write an equation for the reaction of zinc nitrate with aqueous ammonia. I know that zinc hyroxide is produced first but I don't really know how to write an equation for this. This is what I came up with: Zn(NO3)2 + 2OH- --> Zn(OH)2 + 2NO3- I'm not...
March 1, 2010
Satisfy me by improving this and I'll be thankful to you 4ever. In the following paragraphs I will be talking about her life, where and who she performed with, which songs she sang, and what awards she won, and her charity work. It seems like Im missin something around in ...
February 25, 2010
1. list all the possible ages of the children (you don't need to, cos i've done it for you) - eg. (1, 1, 11) (1, 2, 10) etc 2. if you list all this, you will find that there are 2 answers that give a solution of 36. these are: (6, 6, 1) and (9, 2, 2) 3. the master says...
February 3, 2010
Bunyan Lumber, LLC, harvests timber and delivers logs to timber mills for sale. The company was founded 70 years ago by Pete Bunyan. The current CEO is Paula Bunyan, the granddaughter of the founder. The company is currently evaluating a 5,000 acre forest it owns in Oregon. ...
January 30, 2010
I have to introduce myself (character, life) in an original way and I haven't got a clue how to do this. I'm not a very creative person and time is ticking. It's stressing me out. Anyone got ideas ?
January 13, 2010
At room temperature (25 degrees C) butane is a mixture of 72% anti and 28% gauche conformations. Calculate the difference in energy between the gauche and anti confromations. This is how I calculated it but I am not sure I am right: Boltzmann equation: N2/N1 = exp(-(E2-E1)/RT...
November 8, 2009
I would like to know everyone's favorite quotes. My favorite quote is: This is a miracle that happens everytime to those who really love; the more they give,the more they possess. Out of all the quotes, I have to pick top 6, and then everyone in my class will vote for the ...
October 17, 2009
I have to do this writing assignment on anyone I want to. I really like Bella from the movie twilight so i am doing this on her. I have to describe her and all. I already know how she is from my point of view, but I would like to know how she is from yours. so please describe ...
October 12, 2009
I would like to know everyone's opinion on Twilight. rate from 0 to 5. We are supposed to pick one topic, it can be on anything, so I chose twilight. I just need the average rating,thanks.
October 12, 2009
Faryi averaged 50 mph on trip to visit an amusement park 80 miles away and started with a full tank of gas. Her car usually averaged 25 mph each time she purchased. The gas price $2.65 par gallon when she got home. Calculate Faryis time ( in minutes) and the cost to fill...
October 11, 2009
In the year 1910, many people immigrated to the United States-460,935 from northern and Western Europe, 465,356 from eastern and southern Europe, 89,534 from the Americas, 23,533 from Asia, and 1,072 from Africa. Make a bar graph to show this data. What would be an easy ...
September 7, 2009
How can island biogeography be compared to the design of nature reserves? I understandall the things you can do to the nature reserve in terms of bettering it but how is an island similar to a wildlife refugee or reserve (why can you compare them)? can someone please explain?
September 2, 2009
Which would react faster with MeI in aqueous solution: OH- or Et3N? I know that the reaction in aqueous solution would be an Sn1 reaction and so steric hindrance wouldn't have such a great effect. I am not sure which is a better nucleophile out of OH- and Et3N. OH- is ...
May 26, 2009
A set of homogeneous simultaneous equations is given by x + ky = 0 kx + 3y = 0 Calculate the two values of k that lead to non-trivial solutions to these equations and express y in terms of x for the two values. I thought that for the solutions to be no trivial the determinant ...
May 17, 2009
I am attempting to answer a question which asks to explain the sequence of pKaH values for a series of substituted guanidines (NH2)2CNR where R varies. The order is R = H , Ph , CH3CO , MeO , CN , NO2 pKaH = 14.5 , 10.8 , 8.3 , 7.5 , -0.4 , -0.9 I'm not quite sure how to ...
May 4, 2009
Why does CdCO3 have a significantly lower decomposition temperature than CaCO3, despite the similarity in the ionic radii of Ca2+ and Cd2+? I think they both decompose to give the metal oxide and carbon dioxide. Could the polarising ability of Ca compared with Cd have ...
April 23, 2009
louis drew all of the possible diagonals from one vertex of a regular hexagon. Which of these statements is true? A) Each diagonal from this vertex is one of two different lengths B) None of the diagonals forms a line of symmetry of the hexagon. C) The diagonals form four ...
April 22, 2009
a parallel RLC bandpass circuit with C=10nF and Q=10 has a center frequency of 500 krad/s. Find R,L and the two cutoff frequencies. Can you design this circuit using a cascade connection of two first-order filters separated by a follower?
April 20, 2009
For the transfer function Tv(s)=[10(s+5)(s+20)]/[(s+1)(s+100)] is this a low-pass, high-pass, bandpass or bandstop function? estimate the corner frequency(ies) estimate the passband gain what is the output if v1(t)=10cos(1000t+45deg) V??
April 20, 2009
Why is the carbonyl group in tert-butoxycarbonyl group (tBOC) less susceptible to attack from nucleophiles than the carbonyl group in esters such as ethyl acetate? Is this something to do with conjugation?
April 13, 2009
Is this the correct equation for the formation of [Co(NH3)5(ONO)]^2+ from [Co(NH3)5Cl]^2+ ... [Co(NH3)5Cl]^2+ + NO2 --> [Co(NH3)5(ONO)]^2+ + Cl- I'm a bit unsure because the charges don't balance
April 8, 2009
You are having a pool party and invite 2 of your best friends. These two friends each invite two other people. Each of these 2 people invite 2 people that haven't been invited. How many people will be invited if this process continues for four rounds?
March 31, 2009