Homework Help

First of all, I would like to say hello and please excuse my English. I`ll do my best. We (finally) did some experiments in our Chemistry class on Wednesday and my group was the first one to finish them all, so the teacher gave us some extra homework. First experiment: We had to use HCl, NaOH and phenolphthalein. We added HCl and 2-3 drops of phenolphthalein and then we added NaOH. When we added it, a white foam was formed and a gas was emitted. We poured more NaOH and the foam reappeared, but after a very short time it disappeared and the solution turned dark pink (or a combination of red and pink). Why was that foam formed and why did the solution become dark pi…

Hey, I was just wondering what similarities and differences Monotremes, Marsupials,and Placentals had. Thanks Hermione

In my logics class today, we had our midterm. On it was a bonus that I couldn't figure out. It reminded me of something from Calc III (multivariable calculus), but I couldn't nail it down. The question went something like this: Let B be a box, made from spatial dimensions L, length, W, width, and H, height. Let S be all the points around the box that are, at most, 1 unit away from the box. Express S in terms of L, W, and H. How should I have solved this? I had a picture where there was a cube, with a larger, sphere-like object, because the maximums would curve around the vertices of the cube. Did I start it right?

Hey I'm trying to prove a biconditional statement: Let a be an integer. a is congruent to 2 modulo 5 if and only if a squared is congruent to 4 modulo 5. I proved it to the right and and I'm working on proving it to the left. I thought a proof by contradiction would be best but what I run into is the equation 5(b/a+2) = a-2 for some integer b. Now, if I could somehow prove that (b/a+2) is an integer, I would be set because that would contradict our assumption that 5 does not divide a-2 (because we're doing a proof by contradiction). So if anyone could help or point me in the right direction, that would be wonderful. I was hoping these forums would have LaTeX embe…

00 Ok, so here's the provided info: A person invests $10 000 @ 3% per annum Another person invests the same amount THREE YEARS LATER @ 5% per annum. When will they be equal? Here's the equation I came up with: 10 000 (1.03)^(n+3) = 10 000 (1.05)^(n) This yields an answer of ~4.61 Here is my work: 10 000 (1.03)^(n+3) = 10 000 (1.05)^(n) (n+3)log(1.03) = n(log(1.05)) n(log(1.03)) + 3(log(1.03)) = n(log(1.05)) 3(log(1.03)) = n(log(1.05)) - n(log(1.03)) 3(log(1.03)) = n(log1.05 - log1.03) n = ( 3log1.03 ) / ( log1.05 - log1.03) n = ~4.61 Here's the issue: The book uses the equation: 10 000 (1.03)^(n) = 10 00…

Hi everyone! I need help with a mini science project that we are working on. So I have a shoebox that represents a dark attic, a light bulb (the sun), and a tube (toilet paper roll - to give light in the room). Somehow, I have to figure out how to light up the room (shoebox) with the tube (which is inserted at the centre of the top of the shoebox), while a lightbulb (the sun) moves over the roof of the shoebox to see if light will light up the whole thing or not. I can use reflecting surfaces, lenses and/or mirrors in the tube. So I was just wondering, would all I have to do is glue a reflecting surface on the inside of the tube in order for light to enter t…

Here is the spectra of compound X5 and what I think might be X5. Peaks at 163 ppm (13C) and 7.5 ppm(1H) are the fact that is confusing me. No, there is no molecular formula or MS. I understand the last step, but I'm confused by X6 nmr too, because those peaks appear again. The only explanation I came up with is that the H on the carbon atom between the OH and Br is so strongly deshielded. Or is it 2-bromo-2,3,4,5-tetrahydropyridine-3,4-diol

I need help with these 2 centripetal force problems. Help me please 1) An airplane is flying in a horizontal circle at a speed of 128 m/s. The 74.0 kg pilot does not want his centripetal acceleration to exceed 7.00 times free-fall acceleration.\ (a) What is the minimum radius of the circular path? (b) At this radius, what is the net force that maintains circular motion exerted on the pilot by the seat belts, the friction between him and the seat, and so forth? 2) In a popular amusement-park ride, a cylinder of radius 3.00 m is set in rotation at an angular speed of 5.00 rad/s, as shown in Figure 7-20. The floor then drops away, leaving the riders suspended aga…

We had to do a t-test analysis for a lab, and I am confused as to how to answer the question of significance in terms of null/alt hypothesis using confidence intervals. We were to measure the height and weight of 7 males and 12 females in the lab. After doing so and collecting all the data, I got the following: Confidence Intervals based on 95% certainty: Male Height (Mean 174.786): +/- 5.28cm= 169.506cm - 180.066cm Male Weight (Mean 78.143): +/- 20.339kg= 57.804kg - 98.482kg Female Height (Mean 160.83): +/- 5.2426cm= 155.587cm - 166.0726cm Female Weight (Mean 54.30): +/- 8.627kg= 45.672kg - 62.927kg I calculated the CI by multiplying the SE by the conf…

Hey guys, I'm practicing for a thermo test later this week. We have this question in the book: Zipper Problem: A zipper has N links; each links has a state in which it is closed with energy 0 or open with energy [math]\varepsilon[/math]. We require, however, that the zipper can only unzip from the left end, and that the link number s can only open if all links to the left (1,2,...s-1) are already open. (a) Show that the partition function can be summed in the form: [math]Z=\frac{1-\exp{(\frac{-(N+1)\varepsilon}{\tau})}}{1-exp{(\frac{\varepsilon}{\tau})}}[/math] Okay, so I approaced the problem by defining the possible energies as a sum of epsilon(n) where it…

I am doing an experiment to calculate focal lenght of a lens. From a graph of 1/d0 against /di How will I find the focal lenght The points which i have do not touch the x or y axis so I am not sure if I need to extend my line. Also If i know the uncertainty in the distance to the object(do) and distance to the image (di) how can i find the uncertainty in 1/d object and 1/d image Thankyou

Given the reaction A+B=C+D, determine the equilibrium constant if .6mol of C are formed when 1.0 mol of A and B are presented initially. cannot find anything close to this in the book or in the notes, im dieing!

[math] \int_{a}^{b} \frac{dx}{dt}\frac{d^2x}{dt^2}dt = \int_{a}^{b} \frac{d^2x}{dt^2} dx = \frac{1}{2}\frac{dx}{dt} - \frac{1}{2}\frac{dx}{dt} [/math] What I am having trouble is understanding is going from the second step to the third step. I don't understand how you can integrate with respect to dx and still integrate [math] \frac{d^2x}{dt^2} [/math]

Hi, I have a problem with a question. Have NO idea what this means. The number of grams in three moles of solid ammonium chloride is?????

1) Find a vector equation for the plane in R3(3D) with scalar equation 2x − 3y + z = 5 . First,I find three points on the plane and then I used one point as a fixed point in order to find two vectors on the plane by using two other points. Then, I tried to test whether the two vectors are perpendicular to the normal vector of this plane by using cross product. However, I do not get the right normal vector by using my two vectors on the plane? My question is that whether my approach is wrong? If yes, what should I do?

I was originally going to write about the drug war, but I would rather use that for my position paper. I'm looking for something science-related to write about for my exploratory essay. My favorite subjects include biology (major), chemistry, genetics, medicine. I could probably write about psychology or neuroscience. I don't have much interest in Earth Science or Astronomy. -It needs to have 3 different viewpoints. -It needs to be something that I can write about in 900-1000 words (probably not too difficult with most subjects . -I need a minimum of 3 credible sources (I'm not asking you to find sources for me; I am just specifying that it needs to be something th…

Does the f1 generation only occur when you have homozygous parents? Or can someone explain the concept of f1 and f2 generation? What I know so far is that. Your giving to parents for e.g p1 p2 Ww GG x ww gg < step 1 Gametes : WG WG wG wG wg wg wg wg Step 2 F1 ?... I'm confused here , what would be the f1 generation here.. What I do is simply do the following Parent #1 can only give two gametes so which is ... WG wg and parent #2 can only give one which is wg. Now I place them in the punnett square to get WG wg …

This is not a homework assignment, but I didn't know where to post it. I found this question in a book about physics, but there was no explanation. Q: Why do fruit fruit growers set car tires on fire in their orchards in the clear winter mornings? I imagine te answer would be to stop frost from forming, but I don't understand how smoke or soot could do that. The chapter is about wave-like properties of electromagnetic radiation and particles. Could soot act as a black body at 32°F (273 K)?

Hello, I am a little confused about complete dominance. The question I am trying to solve is: A trihybrid pea plant having the genotype AaBbC(1)C(2) is self fertilized there is complete dominance at the A and B loci and co-dominance at the the C loci. What fraction of the progeny will be phenotypically different from the parents?(assume independant assortment). Now I know that the co-dominance C(1)C(2) will show through all the progeny and that A\- & B\- will also be phenotypically alike to the parents. So A\-B\-C(1)C(2) will be phenotypically the same. My question is if A\-bbC(1)C(2), aaB\-C(1)C(2) will cause the progeny to be phenotypically different. …

Hi So I have an essay. I am thinking about doing following topics:- *Genetically modified food and food safety *Human Cloning *Information technology in school. I having a lot of difficulty in finding 2 distinct sources[ either from a book or journal] one which favors the topic, and speaks against the issue. But all im able to find are reports and analysis of what other people are saying, not what the author is trying to say himself. Reason its so difficult is that im not allowed to just use some random internet blog as source, it has to be qualitative, with proper references, atleast 5-10 pages article,like a chapter from book. anyone know where i…

1) If det(AB) = 0, is det(A) or det(B) = 0? Give reasons for your answer. Q1) First, cannot both det(A) or det(B) be 0? If it can, is this statement false. In any case, how can I prove that this is true for all statement since I only know how to find an example to show this is true, which cannot represent all the possibility. 2) Show that if A is singular and Ax = b, b is not equal to 0, has one solution, then it has infinitely many. Q2) How to approach this question? 3) Let A^2 = A. Prove that either A is singular or det(A) = 1. Q3) How can I approach this question?

Hi everyone, I have to write two essays and just need some ideas as what type of things/topics i can include in them, the first one is better, but the second one i dont understand at all. here are the essay titles The importance of pH buffers to life (chemistry) how the structures of macromolecules affect the properties of a cell (biochemistry) If you have any ideas please do let me know thanks

hi there i'm doing a lab report about investigation of the order of the reaction of iodine wif propanone and i find it a bit difficult so i'd like to ask a few questions , hope somebody could help, thz 1.) How does the starch indicator function?why is it added near the end point? (can i just write starch turns blue when meetin iodine? and i really dun noe y it must be added near the end pt==" ) 2.)the tutor requests us to outline another method to follow the kinetics of the reaction. what method?? 3.)and wt means by " mechanism of the reaction"? please help!!!!!!!!!!!!thz a lot><

Two neutral metal spheres X n Y are placed in contact with each other on two insutating supports. A positively charged rod is brought close to X after Y is earthed with a conducting wire. I would like to ask how's the distribution of charges on the spheres.

<font class="Apple-style-span" face="Verdana"><font class="Apple-style-span" color="#0000FF">GM foods also known as Genetically Modified Foods are foods that are changed genetically such as injecting of certain DNA. Such foods have certain advantages such as being pest-resistant, contain more of certain vitamin and etc. However, some of these foods causes allergies to people. </font><font class="Apple-style-span" color="#FF0000">My question : <i>How the GM foods industry develop throughout these years?</i></font></font>